mef - parametrii de discretizare a structurilorfiabilitate si durabilitate - fiability & durability...

Fiabilitate si Durabilitate - Fiability & Durability No 1/ 2014 Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X

1

CONTENTS

Pag.

1. Iulian POPESCU, Ludmila SASS - MODELLING THE MOVEMENT OF MECHANISMS WITH THREE DYADS OF RRT TYPE. GENERAL CASE

3

2. Ludmila SASS, Iulian POPESCU - MODELLING THE MOVEMENT OF MECHANISMS WITH THREE DYADS OF RRT TYPE. PARTICULAR CASES

10

3. Liliana LUCA, Iulian POPESCU - KINEMATICS OF A SCISSORS MECHANISM 18

4. Ion TĂTARU, Cosmin-Mihai MIRIŢOIU, Dan ILINCIOIU - THE VALIDATION OF SOME EXPERIMENTAL RESULTS USING A NUMERICAL METHOD WITH 3D MESHING ELEMENTS

27

5. Mariana PǍTRAŞCU, Doina TǍRǍBUŢǍ, Simona IONESCU, Constantin D. STǍNESCU - RESEARCH ON EXTRACTION PIPES OF DEWAXING PROBES

33

6. Mariana PǍTRAŞCU, Doina TǍRǍBUŢǍ, Simona IONESCU, Constantin D. STǍNESCU - RESEARCH ON EQUIPMENT FOR MINING EQUIPMENT, DEWAXING PROBES

43

7. Cristian PIRGHIE, Ana-Camelia PIRGHIE - CHARACTERIZING THE BEHAVIOR OF THE LUBRICANT FILMS USING MOLECULAR DYNAMICS SIMULATIONS

49

8. Sebastian Marian ZAHARIA, Cristin Olimpiu MORARIU - STATISTICAL PROCESSING OF CENSORED DATA UNDER ACCELERATED RELIABILITY TESTING FOR RADIAL BALL

BEARING

57

9. Marin NEACSA, George ADÎR, Victor ADÎR, Ancuta ADÎR - DYNAMIC STUDY OF THE R-RTT MECHANISM ASSISTED BY AUTODESK INVENTOR

64

10. Stan Marius - THE FAILURE MODES AND THEIR REMEDIATION PROGRESSIVE CAVITY PUMPS USED IN OIL PRODUCTION

71

11. Gheorghe MARC, Maria Loredana BOCA - USING LOGIC PROGRAMMING FOR IMPROVE AND INCREASE THE RELIABILITY OF TOOLS AND EMBEDDED MACHINE TO AVOID SOME

“MISSION CRITICAL „ IN FLEXIBLE MANUFACTURING LINES

78

12. Anastase PRUIU, Traian FLOREA, Daniel MĂRĂȘESCU, Adriana SPORIȘ - CONSIDERATIONS IN DETERMINING ANALYTIC GRAPHICS FUNCTIONAL PARAMETERS OF

MARINE PROPULSION ENGINES

84

13. Anastase PRUIU, Traian FLOREA, Daniel MĂRĂȘESCU,Adriana SPORIȘ - ABOUT ENGINE ROOM VENTILATION ON MERCHANT VESSELS

91

14. Ion BULAC , MATHEMATICAL MODEL FOR DETERMINING KINEMATIC PARAMETERS OF THE CARDAN JOINT MECHANISM WITH TECHNICAL (GEOMETRICAL) DEVIATIONS

97

15. Ion BULAC, THE NUMERICAL STUDY OF THE INFLUENCE OF TECHNICAL (GEOMETRICAL) DEVIATIONS OVER THE KINEMATIC PARAMETERS OF THE CARDAN JOINT

MECHANISM

103

16. Răzvan Bogdan ITU, Iosif DUMITRESCU, Vilhelm ITU - CORRELATING 2K-52MU CUTTING AND LOADING MACHINE WITH TR-5 SCRAPER CONVEYER

110

17. Răzvan Bogdan ITU, Iosif DUMITRESCU, Vilhelm ITU - STUDY OF STABILITY OF 2K-52MU CUTTING-LOADING MACHINE ON TR-5 CONVEYER IN FACES WITH INDIVIDUAL SUPPORT

120

18. Mădălina DUMITRIU - INFLUENCE OF THE SUSPENSION PARAMETERS UPON THE HUNTING MOVEMENT STABILITY OF THE RAILWAY VEHICLES

129

19. Mădălina DUMITRIU - THE DYNAMIC BEHAVIOUR OF THE RAILWAY VEHICLES IN CROSSING AN ISOLATED NIVELMENT DEFECT

137

20. GEORGE Novac - CRANK WEB DEFLECTIONS OF MARINE DIESEL ENGINES 145

21. GEORGE Novac - EXHAUST VALVE WEARS OF MARINE DIESEL ENGINES 151

22. Traian FLOREA, Ligia-Adriana SPORIȘ, Corneliu MOROIANU, Traian Vasile FLOREA, Anastase PRUIU - GRAPHO-ANALYTICAL METHOD FOR CALCULLATING IRREVERSIBILITY

PROCESSES WITH FINITE SPEED

157


2

23. Traian FLOREA, Corneliu MOROIANU, Traian Vasile FLOREA , Ligia Adriana SPORIȘ, Anastase PRUIU - THE COEFFICIENT OF REGENERATIVE LOSSES IN STIRLING MACHINES

165

24. Adina TĂTAR - GAUSSIAN MODEL 174

25. Corneliu MOROIANU, Ligia Adriana SPORIȘ, Traian FLOREA - THE DETERMINATION OF THEORETICAL COMBUSTION TEMPERATURE OF HEAVY FUELS CONSIDERING THE

DISSOCIATION OF WATER VAPOURS FROM THE BURNING GASES

178

26. Corneliu MOROIANU, Traian FLOREA, Ligia Adriana SPORIȘ - MATHEMATICAL MODEL FOR BURNING THE MARINE DIESEL FUEL DROP IN A HOT OXIDIZING ENVIRONMENT

183

27. Ligia-Adriana SPORIȘ, Traian FLOREA, Corneliu MOROIANU - ASUPRA UNUI SISTEM KOROVKIN ÎNTR-UN CON DE FUNCŢII PONDERATE

190

28. Ligia-Adriana SPORIȘ, Corneliu MOROIANU, Traian FLOREA - ASUPRA UNOR ASPECTE CALITATIVE ALE CONVERGENŢEI ÎN SPAŢII LINIARE ORDONATE TOPOLOGICE

193

29. Monica BÂLDEA, Mihaela ISTRATE - PROGRAM FOR THE CALCULATION OF GEOMETRIC OPTIMIZATION OF PRIMARY SEALS

195

30. Iuliana Carmen BĂRBĂCIORU - A NOTE ON (α,β)-CUT IN INTUITIONISTIC FUZZY SETS THEORY

200

31. Iuliana Carmen BĂRBĂCIORU , Viorica Mariela UNGUREANU - LYAPUNOV TYPE OPERATORS ON ORDERED BANACH SPACES

207

32. Mădălina Roxana BUNECI - RANDOMLY GENERATED SUBGROUPOIDS OF X×Z×X 213

33. Mădălina Roxana BUNECI - USING MAPLE FOR VISUALIZATION OF TOPOLOGICAL SUBGROUPOIDS OF X×Z×X

220

34. Elisabeta Mihaela CIORTEA, Mihaela ALDEA - ASPECTS OF A LINEAR PROGRAMMING MODEL DEDICATED TO THE TRANSPORT SYSTEM

227

35. Miodrag IOVANOV - AN EXTREMAL PROBLEM FOR UNIVALENT FUNCTIONS 234

36. Constantin P. BOGDAN, Olimpia PECINGINA - BOOLEAN NORMED ALGEBRAS 240

37. Constantin P. BOGDAN, Olimpia PECINGINA - EXTENSION OF AN ADDITIVE FUNCTIONS NUMARABILE

247

38. Olimpia PECINGINA Constantin P. BOGDAN, - ABN AND METRIC STRUCTURES SPACES OF MEASURES

254

39. Cătălina IANĂŞI - INCREASING RESISTANCE OF STRUCTURAL ELEMENTS WITH CFRP REINFORCEMENTS

261


3

MODELLING THE MOVEMENT OF MECHANISMS

WITH THREE DYADS OF RRT TYPE. GENERAL CASE

Professor Iulian POPESCU,

University of Craiova, member of Romanian Academy of Technical Sciences,

[email protected]

Associate Professor PhD Ludmila SASS,

University of Craiova, Faculty of Mechanics, [email protected]

Abstract. The paper deals with the modeling of mechanisms with three dyads of type RRT and

rotating leading element. Generated trajectories are provided, along with the sliders’ laws of

motions. The mechanism’s operational angular range is limited to the subinterval 00…180

0

because the Grashof conditions are disobeyed. Diagrams depicting the variation of coordinates

corresponding to the points presenting practical interest are presented.

Keywords: mechanism with three RRT dyads, trajectories, movement laws

1. INTRODUCTION

The movement of one of the 1,234,620 possible mechanisms with three dyads dyads [2]

is modeled, in order to reveal its kinematics. It relies on three RRT dyads. As far as we know,

no specialty studies on this mechanism were issued. Instead, mechanisms with 5 and 7 bar

presented interest for scientists. For example [3] presents the structured synthesis of the afford

mentioned mechanism, based on orthogonal trajectories. Distortions and couplers‘ mobility

are considered. [1] includes studies on many mechanisms with rotation couplers and glides,

used for research dedicated spatial vehicles. Further on we will study a mechanism based on

three dyads of RRT type.

2. THE STUDIED MECHANISM

The movement of the mechanism depicted by Fig. 1 was modeled.

Fig. 1. The studied mechanism

mailto:[email protected]


4

It consists of a leading element with a rotation movement AB, the first dyad BCD,

linked to the elements 1 and 0 (base), the second dyad EFG of type RRT connected to the 2-

nd and 3-rd element and the 3-rd RRT dyad HKL, connected to the 4-th and 5-th elements.

The mechanism‘s structural formula [2] is consequently: R-RRT-1+0- RRT-2+3-RRT-4+5.

The mobility degree is: M=3n – 2C5-C4=3.7-2.10=1.

Using the contours‘ method, the following equations can be written:

sin.

cos.

AByy

ABxx

AB

AB (1)

sin.sin.

cos.cos. 3

DCyBCyy

DCSBCxx

DBC

BC (2)

sin.

cos.

BEyy

BExx

BE

BE (3)

sin.sin.sin.

cos.cos.cos.

2

23

GFSyEFyy

GFSSEFxx

DEF

EF (4)

cos.cos.

sin.sin.

3 GFSEFx

GFyEFytg

E

DE

(5)

1 (6)

sin.

cos.

EHyy

EHxx

EH

EH (7)

2 (8)

sin.

cos.

2

23

Syy

SSx

DG

G (9)

sin.sin.sin.

cos.cos.cos.

5

5

LKSyHKyy

LKSxHKxx

GHK

GHK (10)

cos.cos.

sin.sin.

LKxHKx

LKyHKytg

GH

GH

(11)

3. RESULTS

The dimensions considered by our study are: Ax =18; Ay =22; AB=64; BC=81; DC=70;

EF=58; GF=90; HK=47; LK=38; yD=15; EH=26; BE=40; HM=24; 1 =75; 2 =115; =98;

1 .

Fig. 2 depicts the mechanism‘s position for =70o. Fig. 3 depicts the mechanism‘s

subsequent positions, considering that the element AB does not perform full rotations owing

to the adopted sizes which do not meet the Grashof conditions.


5

Fig. 2. The mechanism’s position for =70o

Fig. 3. The mechanism’s subsequent positions

Fig. 4, presenting the trajectories of points B and C, reveal that B describes only a part

from the circle and C‘s race is small.

Fig. 4. The trajectoris of points B and C

The trajectories of points E and D are given in Fig. 4. D moves along a line whilst the

trajectory followed by E is an open rod-type curve.


6

Fig. 5. The trajectories of points E and D

The trajectories described by the points G (in the right side) and F (in the left side) are

depicted by Fig. 6. Both fall in the category of rod-type curves with loops.

Fig. 6. The trajectories described by the points G and F

Fig. 7 depicts the trajectories of points L, H and K. They are similar, but shifted.

Fig. 7. The trajectories of points L, H and K

Fig. 8 is used to reveal a comparison between the trajectories of the points K and M

from the element EF. They are similar, the one corresponding to M being left-shifted to that

corresponding to K.

Fig. 8. A comparison between the trajectories of the points K and M


7

The variations of traces S3 and S2 are provided by Fig. 9. One can see that the

mechanism can operate only for angles within the range 0o…180

o. For angles >180

o

segments appear in the diagram. The program used for simulation joins the ranges‘ limits by

means of lines.

Fig. 9. The variations of traces S3 and S2

Fig. 10 present the variation of the trance S5 with respect to . Also is revealed that the

mechanism cannot operated for o180

Fig. 10. The variation of the trance S5 with respect to

The variations for the coordinates of points E and G, at the input of the 2nd

dyad, given

by Fig. 11, represent a new proof for the mechanism‘s blocking when >180o. The curves

are normal for the rest of the values.


8

Fig. 11. The variations for the coordinates of points E and G, at the input of the 2nd dyad

Similarly in Fig. 12 one presents the variations corresponding to the coordinates of the

points H and L from the input of the 3-rd dyad. Conclusions identical to those from above can

be drawn.

Fig. 12. The variations corresponding to the coordinates of the points H and L

from the input of the 3-rd dyad

The diagrams for the coordinates of the points F, K and M (Fig. 13) reveal the already

mentioned blocking for >180o. An interesting aspect is related to the similarity of the

curves xi and yi respectively.

Fig. 13. The diagrams for the coordinates of the points F, K and M

0.0 100. 200. 300. 400.

Fi [ grd]

-50.

0.0

50.

100.

150.

200.

X EY EX GY G

0.0 100. 200. 300. 400.

Fi [ grd]

-50.

0.0

50.

100.

150.

X HY HX LY L

0.0 100. 200. 300. 400.

Fi [ grd]

-100.

-50.

0.0

50.

100.

150.

X FY FX KY KX MY M


9

4. CONCLUSIONS

- Studies on the mechanism R-RRT-1+0- RRT-2+3-RRT-4+5 were performed.

- Owing to the disobeying of Grashof conditions, the mechanism can operate only for

=0o…180

o.

- The curves generated by the points of interest are open rod curves. Although being

characterized by a high degree, they are not spectacular.

- The variations of the glides‘ traces variations were also represented. Normal diagrams were

obtained.

REFERENCES

1. Brink Jeffrey S. – Reverse kinematic analysis and uncertainty analysis of the space suittle

aft propulsion system (APS) pod lifting fixtura. A thesis, University of Florida, 2005.

2. Popescu Iulian. – Mecanisme. Noi algoritmi şi programe, Reprografia Universităţii din

Craiova, 1997.

3. Shih -Hsi Tong - Design of High-Stiffness Five-Bar and Seven-Bar Linkage Structures by

Using the Concept of Orthogonal Paths. J. Mech. Des. 128(2), pp. 430-435, Jun. 23, 2005.

http://mechanicaldesign.asmedigitalcollection.asme.org/searchresults.aspx?q=Shih%20-Hsi%20Tong&p=1&s=19&c=0&t=


10

MODELLING THE MOVEMENT OF MECHANISMS

WITH THREE DYADS OF RRT TYPE. PARTICULAR CASES

Associate Professor PhD Ludmila SASS,

University of Craiova, Faculty of Mechanics, [email protected]

Professor Iulian POPESCU,

University of Craiova, member of Romanian Academy of Technical Sciences,

[email protected]

Abstract. The paper deals with the modeling of mechanisms with three dyads of type RRT and

rotating leading element. Generated trajectories are provided, along with the sliders’ laws of

motions. Diagrams depicting the variation of coordinates corresponding to the points presenting

practical interest are presented. Two particular cases related to certain sizes of some elements are

studied.

Keywords: mechanism with three RRT dyads, particular cases, trajectories, movement laws

1. INTRODUCTION

This paper deals with the general case of the mechanism with three RRT dyads. [2]

provides a study of a mechanism with 6 bars of a press with certain elements having

adjustable lengths. The kinematics of the mechanism obtained through re-sizing are studied.

[3] presents the structural synthesis of the mechanisms with 5 and 7 bars, based on orthogonal

trajectories, when distortions and couplers‘ mobility are considered. In order to know the

kinematics possibilities of certain variants of the mechanism with three RRT dyads (namely

when some elements are zero sized), the movements of certain particular cases are modeled.

2. STUDIED MECHANISM

The starting point consist in the general case of the studied R-RRT-1+0- RRT-2+3-RRT-

4+5 mechanism [1], depicted by Fig. 1.

Fig. 1. Studied mechanism

mailto:[email protected]:[email protected]


11

Particular cases were obtained varying the sizes of certain elements.

3. RESULTS

The initial values for mechanism‘s sizes are: xA=18; yA=22; AB=64; BC=81; DC=70;

EF=58; GF=90; HK=47; LK=38, yD=15; EH=26; BE=40; HM=24; 1=75; 2=115; =98;

= + 1.

The first particular case corresponds to the case when AB is a rod. Repeated tests

yielded the following modifications: AB=30, DC=35. Fig. 2 depicts a mechanism obtained for

=700. One can see that the point G goes downward the rod from D.

Fig. 2. A mechanism obtained for =70o

Fig. 3 depicts successive positions of the mechanism, revealing that the mechanism is

operational for the entire cycle.

Fig. 3. Successive positions of the mechanism

Fig. 4 reveals that B moves around a full circle and the trace of C is short.


12

Fig. 4. B moves around a full circle and the trace of C is short

The curves from Fig. 5 present the variations of the coordinates of B specific to a circle.

xC has a nonlinear variation whilst yC is constant, its translation being imposed by the glide

from D. The trajectories of E and G, at the input of the 2- nd dyad, represent rod-type curves

and are given by Fig. 6.

Fig. 5. The variations of the coordinates of B specific to a circle

Fig. 6. The trajectories of E and G

The variations for the coordinates of these points are given by Fig. 7. The corresponding

curves are continuous, with symmetric features.

0.0 100. 200. 300. 400.

Fi [ grd]

-50.

0.0

50.

100.

150.

X BY BX CY C


13

Fig. 7. The variations for the coordinates of the points E and G

The trajectories depicted by Fig. 8 correspond to the points H and L, from the input of

the 3-rd dyad, whilst Fig. 9 presents the variations corresponding to their coordinates.

Fig. 8. The trajectories described by the points H and L

The trajectory of L is a rod-type curve, egg-shaped, whilst the trajectory of H reveals

non-symmetric features and some disturbances in the up-right corner. The curves from Fig. 9

present symmetric features.

Fig. 9. The variations for the coordinates of the point L

0.0 100. 200. 300. 400.

Fi [ grd]

0.0

25.

50.

75.

100.

125.

X EY EX GY G

0.0 100. 200. 300. 400.

Fi [ grd]

-20.

0.0

20.

40.

60.

80.

X HY HX LY L


14

The trajectories described by the points F, K and M are depicted by Fig. 10. The up

curve exhibits the same abnormal behavior as the above discussed case for the trajectory of K.

The curves have a high degree and their shape make them fall into the same category with

similar rod-type curves corresponding to other mechanisms.

Fig. 10. The trajectories described by the points F, K and M

Fig. 11 presents the variations for the coordinates of the points F, K and M. One can see

the partial overlapping of the curves xK and xM and a quasi-parallelism for the curves yK and

yM. It means that the points from the element HK have similar trajectories.

Fig. 11. The variations for the coordinates of the points F, K and M

The traces S3, S2 and S5 present the variations from Fig. 12. One can notice the trace S5

with some irregularities for =0o…1700. Traces with similar shapes are sometimes

associated to simpler mechanisms.

0.0 100. 200. 300. 400.

Fi [ grd]

-50.

0.0

50.

100.

150.

X FY LX KY KX MY M


15

Fig. 12. The traces S3, S2 and S5

Another particular case can be obtained when considering zero lengths for the elements

3, 5 and 7. Actually the sizing DC=0 cannot be accomplished because the sliding route of G

should vanish and a condition GF=0 should involve no guidance for L. The only possible

alternative is therefore KL=0. The rest of sizes are preserved.

Fig. 13 depicts the mechanism obtained for =700. Fig. 14 presents the subsequent

positions of this mechanism.

Fig. 13. The mechanism obtained for =70o

Fig. 14. The subsequent positions of the mechanism

The trajectories for the points B, C, D, E, G, H and L will be identical to those presented

above, the only different trajectories corresponding to the points K and M. They are depicted

by Fig. 15 and are rod-type curves similar to other familiar ones.

0.0 100. 200. 300. 400.

Fi [ grd]

0.0

25.

50.

75.

100.

125.

150.

S3S2S5


16

Fig. 15. The trajectories described by the points K and M

The variations of the coordinates of K and M are depicted by Fig. 16. Symmetries and

similarities are detected for the curves corresponding to xK and xM, whilst some non-

uniformities are included by the yK and yM curves.

Fig. 16. The variations of the coordinates of K and M

The shape for the trace S5 is depicted by Fig. 17. It has symmetries and a jump for

>1800. The movement low is interesting and very few mechanisms describe it.

Fig. 17. The shape for the trace S5

4. CONCLUSIONS

- Studies were made concerning the modeling of the movement corresponding to the R-RRT-

1+0- RRT-2+3-RRT-4+5 mechanism for particular cases;

- When searching for particular cases, two of the elements linked to glides cannot be reduced

to zero length, because other glides should remain without guides;

- The first particular case assumed the determination of mechanism‘s sizes such as to make

the leading element to describe full rotations;

- The second particular case involved a null length for an element;

0.0 100. 200. 300. 400.

Fi [ grd]

-25.

0.0

25.

50.

75.

100.

125.

X KY KX MY M

0.0 100. 200. 300. 400.

Fi [ grd]

20.

22.5

25.

27.5

30.

32.5

S5


17

- Trajectories were build and variations for the couplings of interest were provided;

- The resulted trajectories are rod-type curves with high degree whose shape are common,

excepting two cases where some abnormal behaviors were detected;

REFERENCES

1. Popescu Iulian – Mecanisme. Noi algoritmi şi programe, Reprografia Universităţii din

Craiova, 1997.

2. Ren-Chung Soong – An adjustable six-barmechanism with variable input speed for

mechanical forming presses. Transactions of the CSMEIde fa SCGM Vol. 32, No. 3-4,2008.

3. Shih -Hsi Tong - Design of High-Stiffness Five-Bar and Seven-Bar Linkage Structures by

Using the Concept of Orthogonal Paths. J. Mech. Des. 128(2), pp. 430-435, Jun. 23, 2005.

http://mechanicaldesign.asmedigitalcollection.asme.org/searchresults.aspx?q=Shih%20-Hsi%20Tong&p=1&s=19&c=0&t=


18

KINEMATICS OF A SCISSORS MECHANISM

Prof. PhD. Liliana LUCA, Constantin Brancusi University of Targu-Jiu,

[email protected]

Prof. PhD. Iulian POPESCU, University of Craiova,

[email protected]

Abstrac:. We study the kinematics of a scissors mechanism composed of two conductive elements with related

movements and a RTR type dyad. They are written the relations based on contours method and they are given

the results in tables and diagrams.

Keywords: mechanisms for scissors, kinematic analysis, two conductive elements.

1 . INTRODUCTION

The mechanisms from the scissors of debitting metals have been studied over time by

various methods. Many of them were built empirically, on summary calculations. Computers

and new analytical analysis methods allow more detailed studies, which led to improving the

performance of these mechanisms. In the literature, studies continue to show this theme .

Thus, in [1] it is studied the kinematics of a scissors mechanism with a triad, which is

intended for cutting of steel products. They are given the analytical relations based on

contours method and numerous resulted diagrams. In a doctoral thesis [2] they are studied in

detail the mechanisms that ensure shear cutting branches of trees in order to clean them. They

are studied different variants of mechanisms, by modeling them . A detailed dynamic study on

a shear mechanism is given in [3]. The mechanism consists of two dyads .They are calculated

the positions, velocities , accelerations and reactions of couplings .

2. INITIAL DATA

We left from the kinematic scheme of a mechanism given in [4] and shown in Fig. 1.

Items 1 and 4 are both leading, with movements linked by a gear, cog belts, chain

Galle chain or other system. In E and F points are the tips of two knives that run the shear,

point F being on the element 2 which is having a flat movement and point E belongs to

element 3, which also has a flat movement. The symmetry properties of the mechanism allow

for a position of the mechanism the knives to cut the blank (sheet) 5.

3. THE MECHANISM STRUCTURE

The structural diagram of the mechanism is given in Fig. 2. The mobility degree is:

M=3n-2C5-C4=3.4-2.5=2, the mechanism having two conductive elements and a BCC dyad of

RTR type.


19

Fig. 1 Fig. 2

4. THE MECHANISM KINEMATICS

The correlation between angles and is obtained (Fig. 3), through the relations:

Fig. 3


20

θ - α= 90 (1)

Ψ+ α= 270 (2)

Ψ+ θ - 90=270 (3)

Ψ=360- θ (4)

For the kinematic analyze, they are written the relations:

xB =xA+ABcosθ (5)

yB =yA+Absinθ (6)

xC =xD+CDcosψ (7)

YC =YD+CDsinψ (8)

S=yC-yB (9)

S2=yB + BF (10)

S3=yC-CE (11)

xF=xB-a (12)

yF=yB+BF (13)

xE=xC-a (14)

yE=yC-CE (15)

We have adopted the following initial values:

XA = 400: XD = 400: YD = 700: BF = 50: CE = BF: AB = 300 CD = AB: A = BF / 2.

5.THE OBTAINED RESULTS

In the FIG. 4 it is shown the mechanism for = 120 degrees. The image is similar to

that of FIG. 1, so the program is done correctly. The two points of the figure are the E and F

points, that is the tips of the knives for this position.

The successive positions of the mechanism are shown in Fig. 5 for .0...120


21

Fig. 4 Fig. 5

It is noted that while element 1 rotates clockwise, item 4 rotates counterclockwise.

The figure also shows the trajectories of E and F points, thus the trajectories of knives peaks.

At a full rotation they result the successive positions of Fig. 6.

The trajectories of tops knives are circles and race S, meaning the distance between C

and B, is variable (fig. 7 for .0...120 ).

Fig. 6 Fig. 7


22

The complete trajectories of E and F points are shown in Fig. 8, and they are circles

with centers that are different of A and D (Fig. 9), as E and F are located close to the C and B

but offset to their left. In the figure also appear and C and B circles.

Tangent circles of FIG. 9 are described by E and F.

Fig. 8 Fig. 9

The variations of S, S2 and S3 races to the position of the mechanism are shown in

Fig. 11. It is observed that the minimum S, S2 and S3 races are equal to 90 degrees.

0.0 100. 200. 300. 400.

Fi [ grd]

-500.0

0.0

500.

1000.

1500.

SS2S3

Fig. 10


23

Referring to FIG. 11, it is shown that diagrams for coordinates variation of the F and B

points are very close, the shifts being determined by the fact that E and F are also staggered

relative to the BC element.

0.0 100. 200. 300. 400.

Fi [ grd]

-400.0

-200.0

0.0

200.

400.

600.

800.

X BY BX FY F

Fig. 11

The same observation applies to the E and C coordinates in Fig. 12.

0.0 100. 200. 300. 400.

Fi [ grd]

0.0

200.

400.

600.

800.

1000.

X CY CX EY E

Fig. 12


24

For the drawer, it is interesting the contact area between the blade tips. To this, they

were plotted in FIG. 13 the coordinates of E and F points, observing that for of about 90

degrees, YE and YF curves are tangent, meaning the E and F points coincide, this is the

shearing time.

0.0 100. 200. 300. 400.

Fi [ grd]

-250.0

0.0

250.

500.

750.

1000.

X EY EX FY F

Fig. 13

In Table 1 they are also given the numerical results for this area of the operating cycle of the

mechanism.

Table 1

Fi XE YE XF YF

80 427.0933 354.5575 427.0948 345.4423

81 421.9293 353.6933 421.9307 346.3065

82 416.7509 352.9194 416.7523 347.0804

83 411.5598 352.236 411.5611 347.7638

84 406.3575 351.6433 406.3589 348.3565

85 401.1457 351.1415 401.1471 348.8584

86 395.926 350.7307 395.9273 349.2692

87 390.6999 350.4111 390.7012 349.5889

88 385.4688 350.1827 385.4702 349.8172

89 380.2347 350.0457 380.2361 349.9543

90 374.999 350 375.0003 350

91 369.7633 350.0457 369.7647 349.9544

92 364.5291 350.1828 364.5305 349.8173

93 359.2982 350.4112 359.2996 349.5889

94 354.072 350.7308 354.0734 349.2692

95 348.8523 351.1417 348.8537 348.8584


25

96 343.6405 351.6436 343.6419 348.3566

97 338.4383 352.2363 338.4396 347.7639

98 333.2472 352.9197 333.2485 347.0805

99 328.0687 353.6937 328.0701 346.3066

100 322.9046 354.5578 322.9059 345.4424

It appears that indeed, at = 90, YE = YF.

It has been enlarged the diagram of FIG. 13 in the area of interest, finding fig. 14 and

15, where it is clear the tangency of the two circles and the equality of the two ordinates.

80. 85. 90. 95. 100.

Fi [ grd]

300.

325.

350.

375.

400.

425.

450.

X EY EX FY F

Fig. 14

80. 85. 90. 95. 100.

Fi [ grd]

340.

345.

350.

355.

X EY EX FY F

Fig. 15


26

6. CONCLUSIONS

- The studied mechanism satisfies the condition of blank shear.

- Although blades are having a flat movement, they have trajectories that become tangent

when shearing.

- From constructive point of view, these knives can be even on BC element, without the

offset.

- The mechanism is cleverly designed.

REFERENCES

[1]. Berghian, A. B. , Vasiu, Th. , Kinetics study on laboratory model of the mechanisms of

parallel gang sheoars’ type assigned for cutting metallurgical products. Journal of

Engineering annals of Faculty of Engineering Hunedoara, tome V, 2007, fasc. 3.

[2]. Maglioni, C. ,Analysis of reciprocating single blade cutter bars. Tezi di Dottorato.

Universita di Bologna, 2009.

3]. Tyagi, R. K., Verma, M., Borah, S. , Dynamic analysis of a shaper machine cutting tool

and crank pin. Journal of Enviromental Science, Computer Science and Engineering &

Technology, sept.- nov. 2012, vol. 1 no.3, pp. 372-380.

[4]. Kojevnikov, S. N., Esipenko, Ia. I., Raskin, Ia. M. , Mehanizmî. Sparvocinâe posobie. Izd.

Maşinostroenie, Moskva, 1976.

[5] Popescu, I., Luca, L., Cherciu, M., Structura şi cinematica mecanismelor. Aplicaţii. Editura

Sitech, Craiova, 2013.


27

THE VALIDATION OF SOME EXPERIMENTAL RESULTS USING A

NUMERICAL METHOD WITH 3D MESHING ELEMENTS

1Eng. Ion TĂTARU, University of Craiova, Faculty of Mechanics, Department of Applied

Mechanics and Civil Constructions, Calea Bucuresti Street, no. 107, Craiova,Code 200512,

Romania, [email protected] 2Assistant Phd. Eng. Cosmin-Mihai MIRIŢOIU, University of Craiova, Faculty of

Mechanics, Department of Vehicles, Transports and Industrial Engineering, Calea Bucuresti

Street, no. 107, Craiova,Code 200512, Romania, [email protected] 3Prof. phd. eng. Dan ILINCIOIU, University of Craiova, Faculty of Mechanics, Department

of Applied Mechanics and Civil Constructions, Calea Bucuresti Street, no. 107, Craiova,Code

200512, Romania, [email protected]

Abstract. In this paper we present the validation of some experimental results obtained in [1], where there was

presented a device for bars and plates bending which works with strain gauges attached, by using a numerical

method – the finite element analysis. There will be used the same loading variants as in [1]. The structure

analysis was made in Ansys with two types of meshing techniques: map mesh with Brick 8 Node 45 finite element

and auto mesh with Tet 10 Node 187. In the end, we will make comparisons between the used methods and

extract the errors that appear.

Keywords: metallic structure, finite element analysis, mesh, brick elements, tetrahedral elements

Contents:

1. Introduction 2. The previously studied problem 3. Finite element analysis. Meshing and loading cases 4. Conclusions 5. Acknowledgement

1. INTRODUCTION In this paper, starting from the experimental results determined in Miriţoiu (2012)[1],

we will present a finite element analysis validation method with three dimensional elements used for meshing: map mesh with Brick 8 Node 45 finite element and auto mesh with Tet 10 Node 187. In the end we will make comparisons between the results and determine the errors.

According to Călbureanu (2011)[2], the finite element method has appeared and rapidly developed because of the necessity to have a powerful, quick and simple method to solve the complex stress and displacement problems from various engineering areas, like: mechanics, aeronautics, civil engineering, nuclear engineering and marine engineering. This method can be successfully applied also for solving of some problems like: heat transfer, dynamic analysis, fluid mechanics, and so on.

In Quin (2010)[3] the finite element method was used for a complete modeling and calculation for steady state viscoelastic stress analysis. It was made an algorithm formulation of one-dimensional case and extended to a generalized one. The numerical examples were given for two cases: one-dimensional and two-dimensional. There are studied the effects of


28

the load speed, material properties and pressure distributions at the contact surface. In Karunakaran (2011)[4] is presented a finite element procedure for thermal analysis in pulsed current gas tungsten arc welding (abbreviated PCGTAW) of Az 31B magnesium alloy sheets. The studied material can be used in aircraft, automobile and high-speed train components. The software Ansys was used for finite element analysis and the results obtained were compared with experimental ones. The conclusion of the study was that the finite element analysis using Ansys can be effectively used to model PCGTAW process for finding temperature distribution.

In El-Asfoury (2009)[5], the finite element analysis was used for a static and dynamic study of pelvic bone. The bone was subjected to quasi-static and dynamic loading conditions simulating the effect of both weight gain and impact.

The mechanism of damping in welded structures was studied in Singh (2010)[6]. The

study emphasized the theoretical investigation of slip damping in layered and jointed welded

cantilever structures using finite element approach. The developed finite element model

shows that the damping capacity of such structures is influenced by a number of vital

parameters, such as: pressure distribution, kinematical coefficient of friction and micro-slip at

the interfaces, amplitude, vibration frequency, specimen length and thickness.

2. THE PREVIOUSLY STUDIED PROBLEM In [1], a device for metallic structures (bars, plates) bending and stress measurement

was studied. The studied metallic structure is presented in fig. 1 and the used device is presented in fig. 2. According to [1], the device works with strain gauges (shown in fig. 3 and 4).

Fig. 2. The studied device [1]

Fig. 1. The studied metallic structure [1]

Fig. 3. The first half bridge [1]

Fig. 4. The second half bridge [1]


29

Two loading variants were considered: variant 1- P= 701,55 daN, variant 2- F= 507,56 daN. The stresses obtained, for each loading case, are shown in fig. 5 and 6.

3. FINITE ELEMENT ANALYSIS. MESHING AND LOADING CASES For the first loading case, there was used a mapped mesh, with Brick 8 Node 45 finite

elements (fig. 7). The stress distribution for the whole structure is presented in fig. 7 and in fig. 8 the stress distribution in the area of the first half bridge is presented. From fig. 8 it can be seen that the stress distribution from the second half bridge area is almost 0. The stress distribution from the first half bridge is presented in fig. 9 for variant 1. The mesh type in variant 2 (with Tet 10 Node 187 meshing elements) is presented in fig. 10. In fig. 11 we have presented the stress distribution for the whole structure and in fig. 12 the stress distribution in the first half bridge area.

Fig. 5. The stress values in the first Fig. 6. The stress values in the second

loading case [1] loading case [1]

Fig. 7. Mesh type (variant 1) Fig. 8. Stress distribution (variant 1)


30

Important remark: in the area of the second half bridge the stress values are very

small (according to fig. 8. and 11) and will be approximated being zero in the following parts of the paper (the real values are: for variant 1- 0,12∙10

-4 and for variant 2- 0,006736).

Fig. 9. Stress distribution (first half bridge) Fig. 10. Mesh type (variant 2)

Fig. 11. Stress distribution (variant 2) Fig. 12. Stress distribution (first half bridge)


31

4. CONCLUSIONS In the table 1 we have listed the results obtained with the three-dimensional meshing

elements for the considered cases.

Table 1. The results obtained with the finite element analysis

Stress type Value [MPa]

Method Finite element analysis

Loading variants First loading variant Second loading variant

First half bridge 32,8125 69,125

Second half bridge 0,12∙10-4

0,006736

The results obtained with the experimental method from [1] are listed in table 2.

Table 2. Stress results from [1]

Experimental method

Stress type First half bridge Second half bridge First half bridge Second half bridge

Loading variant 1 2 1 2

Stress Value

[MPa] 34,269 0,0042094 72,871 0,0079752

We have determined the errors between the experimental and numerical method with

relation (1).

In (1) we have marked with: ε1 – the stress obtained with the experimental method, ε2

– the stress obtained with the numerical method and with εmax the maximul stress. The errors obtained are listed in table 3.

Table 3. Errors obtained between the experimental and numerical methods

Numerical method/ Experimental method Stress type First half bridge Second half

bridge First half bridge Second half

bridge Loading variant 1 1 2 2

Error [%] 4,25 0 5,141 0

From the table 3 we can extract the next conclusions: - the experimental method from [1] gives similar results like the numerical method, so

the strain gauges were glued well on the structure; - the errors are very small (under 6%); - the stress values obtained from the second half bridge are 0 (because the bars are not

loaded); - the stress values obtained from the first half bridge are different from zero, because

the area is loaded by the forces considered from the two loading variants;

100%max

21

(1)


32

- both methods can be successfully used for metallic structures stress calculus; - the errors are higher when the tetrahedral elements are used, because this type of

elements insert higher errors than the hexahedral ones (used in the first loading variant), fact that was expected before using this type of elements.

4. ACKNOWLEDGEMENT

This work was supported by the strategic grant POSDRU/159/1.S/S/133255, Project

ID 133255 (2014), co-financed by the European Social Fund within the Sectorial Operational

Program Human Resources Development 2007-2013.

REFERENCES Miriţoiu, C., M., (2012) A Simple but Accurate Device and Method Used for Bending and Stress Measurement of Metallic Structures, IOSR Journal of Engineering (IOSRJEN), 2(6), 1334-1339 Călbureanu, M., (2011) Introduction to finite element analysis, Universitaria Publishing House Quin, F., Yu, Y., Rudolphi, T., (2010) Finite Element Modeling of Viscoelastic Stress Analysis under Moving Loads, International Journal of Mechanical and Materials Engineering, 4(1), 226-233 Karunakaran, N., Balasubramanian, V., (2011) Multipurpose Three Dimensional Finite Element Procedure for Thermal Analysis in Pulsed Current Gas Tungsten Arc Welding of AZ 31B Magnesium Alloy Sheets, International Journal of Aerospace and Mechanical Engineering, 5(4), 267- 274 El-Asfoury, El-Hadek, M., A., (2009) Static and Dynamic Three-Dimensional Finite Element Analysis of Pelvic Bone, International Journal of Engineering and Applied Sciences, 5 (5), 315-321 Singh, B., Nanda, B., K., (2010) Mechanism of Damping in Welded Structures using Finite Element Approach, International Journal of Information and Mathematical Sciences, 6(2), 138-142 Ajovalaist, A., Zucarello, B., (2005) Local Reinforcement Effect of a Strain Gauge Installation on Low Modulus Materials, The Journal of Strain Analysis for Engineering Design, 40 (7), 643-653 Atanackovic, T., (2000) Theory of Elasticity for Scientists and Engineers, Published by Birkhauser Boston Avalle, M., Goglio, L., (1997) Static lateral compression of aluminium tubes: Strain gauge measurements and discussion of theoretical models, The Journal of Strain Analysis for Engineering Design, 32 (5), 335-343 Huttelmaier, H., P., Glockner, P., G., (1985) Stresses and displacements due to underground mining using a finite element procedure, Geotechnical and Geological Engineering, 3(1), 49-63 Korayem, M., H., Heidari, A., Nikoobin, A., (2008) Maximum allowable dynamic load of flexible mobile manipulators using finite element approach, The International Journal of Advanced Manufacturing Technology, 36 (5,6), 606-617 Kulkarni, S., D., Kapuria, S., (2007) A new discrete Kirchhoff quadrilateral element based on the third-order theory for composite plates, Computational Mechanics, 39 (3), 237-246 Mao, S., Shi, Z., (2009) High accuracy analysis of two nonconforming plate elements, Numerische Mathematik, 111 (3), 407-443

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33

RESEARCH ON EXTRACTION PIPES OF DEWAXING PROBES

Drd. Eng Mariana PǍTRAŞCU (ANTONESCU); e-mail: [email protected]

Drd.Eng Doina TǍRǍBUŢǍ (ENE);e-mail: [email protected];

Matemat.drd.Simona IONESCU: e-mail: [email protected]

Prof.univ.Emerit. Dr.eng. Constantin D. STǍNESCU e-mail:[email protected]

Polytechnic University of Bucharest;

Abstract: In this paper I present dewaxing methods of extraction wells pipes. Dewaxing tubing of the

probes is done by mechanical, thermal, chemical Research undertaken on cleaning oil pipelines and networks as

for transport crude oil and petroleum products shows that within them is deposited drilling mud and paraffin

and cerezima which reduces pipe diameter and fluid flow velocity .In this context it is necessary, periods of

cleaning these pipes with solutions and special devices.

Keywords : dewaxing , pipeline, rehabilitation

1. INTRODUCTION

During operation of a hydrocarbon reservoir, and, in the probe and surface facilities is

submitted, a large amount of particles as a solid.

Paraffin wax or oil is the formula CnH2n +2 solid phase respectively C16H34 to

C64H130., Respectively, a mixture of liquid components, solid products (paraffin,

microcrystalline wax) as fine crystals, which add substance asphalt, resins sand, shale, clay.

After weight content of paraffin oils from Romania are divided into three categories:

- Waxy crude oils containing less than 2% paraffin;

- Semiparafinoase crude oils with a content of 1-2% paraffin;

- The wax crude oils containing less than 1% paraffin.

Separation of oil and paraffin deposition is greatly influenced by temperature and

pressure.

By lowering the temperature to reach a crystallization onset temperature of the wax,

and the lower part of pressure oil out of the solution, so that the dissolution capacity of the

solids falls.

Beginning of crystallization temperature is between 35 € - 38 ¤ C, as corresponds to

the paraffin deposition depths between 600 ... 1000 m as geothermal gradient and oil quality.

Paraffin oil is separated from the small crystals, which, due to movement of the fluid in

contact with each other, aglomerandu being around a nucleus, which may be a foreign body

such as sand, shale or fine metal particles resulted from the These clusters of corrosion

phenomena paraffin crystals are deposited on the walls of tubing, a phenomenon accentuated

tubing roughness.

Paraffin deposition is accentuated intermittently producing wells due to repeated oil

leaks on the interior walls of tubing.



34

Areas where deposition occurs parafinii as conditions are:

- Layer pores - in the area immediately surrounding the hole made by the probe;

- The exit of the column operating layer of shallow wells

- Inside the column tubing the wells sucker for great depths;

- Inside the plant surface and the mixing pipe.

Paraffin deposits produce reducing production capacity wells, reducing fluid flow through

section tubing.

Methods to reduce and control paraffin deposition are:

- Prevention methods which prevent or delay the precipitation and deposition of paraffin;

- Methods for cleaning and removal of paraffin deposited in waxy crude equipment by

circulating

2. DEWAXING MECHANICAL TUBING WELLS ERUPTING

Dewaxing operation is performed using mobile winch and consists of the following

phases:

• Install the hard pole connector (which can attach a jar) and paraffin cleaner type A or

type B;

• insert the pipe assembly dewaxing;

• pressure mounts bronze rings and rubber seals;

• Install the downspout dewaxing glands, which is mounted above the last valve head

rash;

• Link to drain the casing;

Fig 1. Hydro hook

Fig 2. banana Guy

brake cleaner

Fig 3. brake cleaner

with variable

diameter and blade

furniture

Fig 4. brake cleaner with

furniture blade with straight

pins and brake cleaner with

spiral blades


35

After the installation has been installed and controlled, open upper valve head slowly

eruption, noting if the hose is not leaking. Cleaner in the tubing down to the depth of paraffin

deposition.

After the cleaning tubing, pull the pipe cleaner, close the upper valve head eruption,

reduce pressure inside the casing, remove the stuffing and extracted cleaner.

To clean wax from the tubing walls or columns operation, use the lower scale and

other non-standard cleaners such as column hook dewaxing operation (Fig. 1) banana cleaner

(Fig. 2 ) with variable diameter and blade cleaner furniture (fig. 3), furniture cleaner blade and

guide pins, washers spiral blades (fig. 4)

3. DEWAXING MECHANICAL TUBING WELLS IN ARTIFICIAL

ERUPTION

Dewaxing column tubing wells operating in artificial eruption can use the same probes

used dewaxing natural eruption, but it can also use a special cleaner compressed acted

requiring installation of a special device at the head of eruption . Cleanser paraffin acted

compressed (Fig. 5) is made of two metal plates welded to the cross, which is welded a series

of fins arranged inclined. On top cleaner has a reducer fitted externally with radial notches to

be trapped and removed.

Equipment needed for the use of cleaner requires compressed, schematic in Fig. 5

consists of a launching tube made from a 3 1/2 in the upper part provided with a bumper

cover, the side with the connecting pipes 2, and a socket stop flap at the bottom and another A

lockable side of half the drain pressur.

Fig. 5. Diagram of dewaxing acted with cleaner compressed gas 1 separator, 2 spring detent 3-cap Silenced

In column tubing under parafining depth, a reduction seat mounts, fitted with silencer

to stop cleaner requires.

Dewaxing operation with this cleaner as follows:


36

Release device is mounted on the upper valve head eruption. Remove its cap and

insert cleaner who sits on the flip stop.

It will stop the injection of gas through the annular space of the well by closing the

valve I, II then closes and valve through which fluid from the probe mixture. III then opens

valve at the top of the head of the eruption and acts on the throttle stops, allowing cleaner

requires the probe to descend through tubing under its own weight.

After the release pipe cleaner requires the injection of compressed gas begins by

opening the valve IV stick to push cleaner requires to seat reducer. In this time of scraped

cleaner wax deposited on the tubing wall.

It will stop the injection of gas through the tubing when the cleaner came in

termination point by closing the valve IV and will switch to normal injection gas through the

annular space by opening ventiluluui I.

- Evacuation probe mixture oil and gas and directing it to the separator by launching

device, opening the valve V.

Raising cleaner requires the device launch probe fluid. Cleanser flap switch lid damper stop

kicking, but can not return to the probe because the flap returns immediately closed position

under the action of a spring.

Open valve II to return oil to the normal route through arm rash head and close valves

III and V. To remove the head cleaners of dewaxing release gas will leak through the opening

below the 1/2 inch and then remove the lid of the launch.

4. DEWAXING MECHANICAL TUBING AND SUCKER RODS IN PUMPING

WELLS WITH PIPES

Dewaxing tubing in pumping wells with pipes is accomplished by means of coil

cleaners called scrapers (fig. 6).

A scraper has a cylindrical body of steel with a diameter of less than 4-5 mm than the

inside diameter of the tubing is inserted. On the body are processed three cutter wrapped by

the left propeller. Ends is properly threaded plugs that are inserted pole size.

Fig. 6. Cleaner helical

Cleaners are inserted between two poles socket instead of pumping the entire length of

the paraffin deposition zone.


37

Cleaning paraffin column tubing, in this case, is made continuously by moving up and

down lining sucker for a length equal to the pumping stroke length during normal operation,

or periodically throughout the the paraffin deposition by executing a maneuver to seal pipes

of pumping over a distance greater than the distance between two cleaners.

Wells equipped with pumps that are included with sucker rods, not bobbing pump

mounting location during these maneuvers using a coupling device - called bayonet coupling

Dontov (Fig. 7.a), interlaced in the rod string at a depth greater than that which is deposited

paraffin.

The device consists of two parts:

- Barrel or bayonet scabbard fitted inside two parallel channels of special shape (Fig. 7 b);

- Hanging rod entering the bayonet scabbard and fix this with two wings, which engages

in the channels formed in the bayonet (Figure 7.c)

Fig 7 Bayonet Dontov

a-bayonet coupled device; b- bayonet scabbard; c-hanger rod with wings.

To leave a bayonet displacement of the weight of the ram pipes on the device rotates

gasket and then pull right up. To leave bayonet coupling down and automatically fins hanging

rod sliding on sloping channels and stop the clogged portion thereof.

In pumping wells equipped with pumps that are included with tubing not need this

device because of the pump piston can be lifted by sucker rods without leaking pipes.

A better cleaning tubing paraffin, along with cleaning rod pumping paraffin seal is

achieved by extracting sucker for changing pump P (R) or change piston pumps type T.

Dewaxing sucker is by direct scraping and extracting them from the probe.


38

For scraping usually use a wire that wraps around the pipe and you stretched with two

rings (handles) of a probe while the probe is extracted from the pumping rod string. This

process is disadvantageous, presenting fire and some of the wax flows into the probe.

Instead use wire clippers dewaxing, which have two blades each provided with a

semicircular notch. When the blades are tight form an opening equal to the pipe section.

Were constructed and used sporadically site some special cleaners to clean wax from the

sucker rods.

Fig.8 Cleaner for pipes of pumping rubber wipers Fig.9 Tables of sucker rods with metal knife.

Figure 8 shows schematically a device for cleaning the wiper rubber mounts instead of

the polished rod stuffing box. This device has two semi-circular or helical rubber tiles that

sucker rubs during extraction of the probe. Grated paraffin flow through two side arms. Fins

pressed by a spring prevents penetration of wax scraped tubing. In Figure 9 is outlined wax

cleansing device on sucker rods with a metal knife.

5. THERMAL METHODS DEWAXING EXTRACTION PIPES FROM WELLS

This method is achieved by raising the temperature in the deposition of wax, that it

dissolve and be entrained in the upward fluid probe.

Heat to melt the wax is obtained by:

- Circulation of heat in the probe;

- Using an electric heating tubing.

Dewaxing tubing by circulating a heating using steam as heat, which is introduced into the

annular space and out through tubing with heated crude oil.


39

Wells in artificial eruption, steam is introduced with the probe gas is injected in

ascension.

Pumping wells in leak pressure column and then steam generator is connected to the column.

Dewaxing pipes these probes are conducted in four phases:

1) steam is injected into the column, keeping the pump in operation for about 15

minutes;

2) is continuous steam injection, the probe stops for 15 minutes to heat the oil and

melt the wax resting on the walls of the pipes;

3) Replace the probe in use for 15 minutes, along with steam injection;

4) The new probe stops about. 15 minutes for heating oil at rest. Steam injection stops

and the probe is passed in continuous operation.

Probe can be inserted into another fluid heated by direct circulation or reverse.

Using the hot fluid has the advantage that it does not change the volume by giving

stored heat, condensation from steam, its volume shrinks more traffic. The heat used is crude

semiparafinos glazed or heated to 60-800 C. Water, although it has better thermal capacity is

not recommended as it can have a harmful influence on productivity layer exploited.

Dewaxing tubing with electrical heating is electrical energy conversion in heat energy.

Heaters are two types:

- Electric resistance heater;

- Electric heater induction.

Electric resistance heater (Fig. 10) consists of two conductors connected in series, with

different resistant. These conductors are column tubing equipped with plugs isolated column

operation.

Tubing heat from the electrical current will be higher than in column operation, due to

the difference of section (A Pipe > A column → then Rt> Rc) and the law Joule - Lenz result

Qt> Qc or:

where Q is the amount of heat that is released (in pipes Qt, Qc column);

I - the electric current;

R - the electrical resistance of the column tubing;

R - the electrical resistance of the column operation;

t - the amount of electrical current passing through the two conductors.

When using such an electric heater for dewaxing must ensure the necessary elements

insulation tubing from column exploitation insulating sleeves and a contact device at the

lower end of the pipe to close the electrical circuit between the pipes and columns.

Operated wells in pumping circuit consists of pipes and tubing, the focal point being the

piston pump shallow wells or springs contact device mounted on poles in depth parafining.

(1)


40

Fig.10 Scheme dewaxing tubing with electric heater Fig.11 Scheme dewaxing tubing with induction heater

Induction heater (fig. 11) consists of a cylindrical body of metal (tubing), wearing

insulating material over which a coil is wound with copper wire, covered in turn with

insulating material and the entire assembly is locked in a shell.

The lower end of the coil are welded to the metal body, and the upper contact device

connects the column operation. The heater is mounted in the column pipe at a certain depth,

the power will be done through the column tubing and operating connected to a power source.

Warming is caused by induced AC.

6. CHEMICAL METHODS OF DEWAXING EXTRACTION PIPES

These methods consist in placing the tubing of a solvent, either pure or dissolved in a

liquid.

Type of solvent required for each probe, the amount required for treatment, the

proportion from transport agent, duration and frequency of treatment is determined

experimentally by taking samples of raw wax clean the tubing walls and reviewing the

corresponding solubility of different solvents in the same conditions.

To dissolve the wax can be used: carbon disulfide, carbon tetrachloride, methylene

chloride, chloroform, butane, either as a single component or as a mixture of several solvents.

For the transport of solvent into the wellbore may be used: gasoline, kerosene, diesel oil

glazed.

Dewaxing pipes eruptive wells following sequence:

- Insert the solvent extraction pipes, where allowed time of 3 - 4 o'clock maintaining probe

closed to dissolve the paraffin.

- Opens probe for a short time for cleaning.

- Close the probe and insert again solvent.

The operation is repeated several times in succession mentioned, then restore normal

function probe.


41

Introducing the solvent with a higher density than the fluid in the probe is made by

The lubrication.

Pumping wells in traffic enforcement is indicated solvent.

It increases the flow probe increasing pumping elements so reduce submergenta.

Solvent is introduced into the annular space operating column - tubing is then sucked by the

pump with fluid discharged in the probe and tubing.

When the solvent reaches the pump head are directed into the annular space and

movement is mix oil - cleaning solvent to obtain paraffin deposition in production tubing.

Before reinserting the circuit oil mixture - solvent was removed from the probe will be a

separation of paraffin involved in the probe.

Dewaxing pipe mixture can be made about: mechanical, thermal, chemical.

Mechanical dewaxing paraffin pipeline is made using special cleaners called godevile.

Pig (Fig. 12) is a device composed of a central rod with one or more hinges, which is fixed to

a group of scraper wings, levers, having rollers at both ends needle for guide and some

supports for the fitting some of seals.

The joints allow Pig to pass easily through pipe bends. Seals made of leather or

synthetic rubber are designed to set in motion Pig in the fluid and push the wax scraped from

the pipe.

Gone are some blades scraping steel wax cleansing role. Gears, made of steel guides

cleaner and prevents its rotation. Launching and receiving godevilelor be done some special

connection pipes mixture, called the bypass pipe, fitted with valves to direct fluid required a

short insertion and removal of these cleaners.

Wheel steering:

Fig. 12. Godevil

Dewaxing about termicaa pipes is done by injecting superheated steam or hot oil.

Dewaxing chimica pipes are made with solvents that establish quantitative and

qualitative experimentally. Prevention of paraffin deposit pipe is cleaned by introducing

periodical liquid stream of pure solvent plugs.


42

7. CONCLUSIONS

Research undertaken on cleaning oil pipelines and networks as for transport crude oil

and petroleum products shows that within them is deposited drilling mud and paraffin and

cerezima which reduces pipe diameter and fluid flow velocity. In this context it is necessary,

periods of cleaning these pipes with solutions and special devices.

REFERENCES

[1.] Branzan Ovidiu,Studiul prelungirii durabilitatii conductelor de transport produse

petroliere ,2007

[2.] Luerenich Sren-Untersuchun gen zur Bildung Korrosiver Belage inolge feuerten

Crasturbinen,Hachen 2009

[3.] Schutze,Michael-Conrosion and enviconmental degradation NewYork 2000


43

RESEARCH ON EQUIPMENT FOR MINING EQUIPMENT,

DEWAXING PROBES

Drd. Eng Mariana PǍTRAŞCU (ANTONESCU); e-mail: [email protected]

Drd.Eng Doina TǍRǍBUŢǍ (ENE);e-mail: [email protected];

Matemat.drd.Simona IONESCU: e-mail: [email protected]

Prof.univ.Emerit. Dr.eng. Constantin D. STǍNESCU

e-mail:[email protected]

Polytechnic University of Bucharest;

Abstract :In thisprezentswouldrather on general aspects of the art equipment for dewaxingequipment

extraction wells Research undertaken on cleaning oil pipelines and networks as for transport crude oil and

petroleum products shows that within them is deposited drilling mud and paraffin and cerezima which reduces

pipe diameter and fluid flow velocity

In this context it is necessary, periods of cleaning these pipes with solutions and special devices

Keyworbs : dewaxing probe, pipe

1 INTRODUCTION

During operation of a hydrocarbon reservoir in the probe and the surface facilities is

submitted, a large amount of solid particles appropriate comb.

Paraffin wax oil or solid phase represents the formulaCnH2n+2respectivelyC16H34 up

toC64H130.,respectively, a mixture of liquid components, solid products (paraffin,

microcrystalline wax) as fine crystals, which add substance asphalt, resins, sand, shale, clay

After the weight content of paraffin naphthas in Romania is divided into three

categories:

- Paraffin oils containing less than 2% paraffin;

- Semiparafinoase oils with a content of 1-2% paraffin;

- Glazed oils containing less than 1% paraffin.

Separation and paraffin deposition in oil is much influenced by temperature and pressure.

The depression of the temperature reaching a crystallization onset temperature of the

wax, and the depression of a part of the pressure oil out of the solution, so that the dissolution

capacity of the solids falls.

Beginning of crystallization temperature is between 35 ¤ - 38

¤ C, corresponds to the

paraffin deposition depths between 600 ... 1000 m as geothermal gradient and quality of crude

oil.

Paraffin oil is separated from the small crystals, which, due to movement of the fluid

in contact with each other, making the being around a nucleus, which may be a foreign body

such as sand, shale or fine metal particles resulted from the corrosion phenomena paraffin

these clusters of crystals are deposited on the walls of tubing, a phenomenon accentuated

tubing roughness.



44

Filing paraffin is sharp wells producing intermittent, due to repeated oil spills on the

inner walls of the tubing.

Areas where deposition occurs parafinii under the conditions specified are:

- The pores layer - the immediate area of hole made by Probe;

- The exit of the column operating layer of shallow wells

- Inside the column tubing wells sucker for great depths;

- The surface and inside of the mixing pipe.

Produce paraffin deposits decreasing production capacity wells, reducing fluid flow

through section tubing.

Methods for reducing and combating parafinǎ deposits are:

- Methods of prevention which prohibits evitǎ or paraffin precipitation and deposition;

- Clean and methods of paraffin removal of the equipment submitted that go paraffin oil.

2. PREVENT SETTLING PARAFFIN.

Keeping her training paraffin matter and appropriate comb crystals or agglomerates of

crystals on the surface and solubility in paraffin oil flow regime depends on the mixture and

thermodynamic regime of the probe .

For these reasons the following means to prevent shows of cellulose:

a) Maintenance of gas in solution by choosing a suitable operating rate higher

pressure and saturation pressure by providing the lowest possible pressure drop in the

tubing.

b) Avoid sudden pressure change by FOLLOWING measure by:

- Avoid using bottom nozzles;

- Avoid using columns telescopic tubing;

- Avoid possible to start using valves in the pipes parafining extraction;

- Carefully controlling the tightness of plugs and body tubing.

c) Influence of temperature conditions by:

- Loss prevention caldurǎ the path of the oil;

- Heating the oil before it reaches the foot of the probe with a paraffin deposit

temperaturǎ favorable views.

d) Avoiding flicker and pulsations in the operation of the probe. e) The use of surface active agents such as paraffin retardants, working in meaning to

preventing accumulation of paraffin crystals by maintaining the suspension of

large amounts of fine crystals.

f) Ensure smooth movement by covering the inside of the tubing with special paints or plastics to prevent adherence of paraffin crystals. In these lakes or plastic

coatings, even if not achieved total prevention of paraffin deposition, the

deposition of wax inside tubing is long overdue and it is relatively easy cleaning

due to poor adhesion of the wax film plastic.

g) The use of a pulsed ultrasound generator, the effect of the accumulation of gas bubbles on the interior walls of the pipe, which change the structure of the

molecule will influence the shrinkage of the wax crystal formation temperature.


45

Methods for removal of wax deposited on the inner walls of the column Probe tubing,

sucker rods and on the internal walls of the mixing pipes, consisting of:

cleaning about Mechanics;

Thermal cleaning;

chemical cleaning. Each of these methods they differ depending on the operating system of the probes and

the nature of their equipment.

3. INSTALLATION DEWAXING MECHANICALLY.

Mechanical methods consist of scraping paraffin dewaxing to be submitted during the

operation of paraffinic hydrocarbons on metal surfaces through which they travel, using

special devices called knives.

Mechanical cleaning wax knives are inserted tubing periodically erupting wells

operated natural and artificial hives that are envisaged with special dewaxing plant.

Dewaxing assembly consists of the following elements:

dewaxing knife;

a heavy stick (or rod) mounted above the blade to ensure its descent producing wells with high flow or bursts;

a special connection cable or wire;

cable or wire cutter launch and maneuver;

adewaxing pipe (head or head pistonaredewaxing);

a guide pulley cable or wire;

winch. After the dimensions and construction components are three main types of dewaxing:

dewaxing heavy type;

dewaxing medium type;

dewaxing of light type; Dewaxing of heavy type (Fig. 1) consists of: purifying tubular type A or type B

lamellar hard, heavy pole, fixed connection cable diameter 12-16 mm piston head and a winch

column intervention. Guidance cable is over crownblock tower production.

Dewaxing medium type (Fig. 2) consists of: Paraffin Cleaner easily laminated type C

or type D curǎţitor knives, heavy stick, removable connector, cable diameter 7 ... 8 mm, type

A head start for dewaxingdewaxing and mobile hoist.

Dewaxing easily type consists of: Cleaner easily laminated type C, heavy stick,

removable pipe, wire diameter 1.9 ... 2.2 mm, head wire B launch, over whose roll is guiding

wire and a hand winch type Yakovlev and Halliburton, which typically are used at different

probe measurements. Dewaxing mechanical eruption tubing wells is carried out using

standard paraffin cleaners which are schematically in Figure 3. and 4.

These knives have the upper thread with a pin which is screwed to a heavy pole.


46

Heavy pole is a steel cylindrical Scheduled to a head pin and the other to jack the

thread sucker. Its role is to ensure the weight of the descending knife NECESSARY,

especially in wells with high pressure natural erupting respectively wells producing large

volumes or in bursts.

Fig. 1.Plant type dewaxing heavy

1 - Clean tubular or tubular type B, 2-pole heavy 3-

permanent connection, 4-wire 12 ... 16mm diameter., 5-

head piston column, 6 - winch intervention

Fig. 2 medium type dewaxing plant

1 Paraffin Cleaner easily laminated type C or type

D washers knives, 2 - heavy pole, 3-removable

connector, 4-wire with diameter 7 ... 8 mm, 5-head

type dewaxing launch, 6 - winch dewaxing phone.

a b c d

Fig. 3. Paraffin cleaners for wells in eruption

a) cleaners tubular type –A; b) cleaners hard lamellar type- B ; c.)cleaners easily slide type- C;

d.) cleaners with knives type- D.

-cleaner tube (sheath) - A (fig.3.a.) consists of a tubular body with a longitudinal cut,

with larger diameter at the bottom (a few mm less than the inside diameter of the pipe decǎt

which introduces ). The terminal body 450 is cut to provide the advancement easier, but also a

better scraping paraffin on the walls of the tubing.


47

At the top is welded reducer for heavy pole now.

-cleaner hard lamellar type B (Fig. 3.b.) consists of a steel blade of 15 mm and length

of 1200 mm wind the strand in a sense the opposite upper and lower side, avoiding the

possibility rotation of the pipe cleaner.

-cleaners easily laminated type C (Figure 3.c) consists of a steel blade with a thickness

of 7 mm and a length of 500 mm. Body surface cleaners, twisted up and down in ways

contrary, are envisaged some windows that can easily switch from oil extraction pipe.

-D Cleanser knives (butterfly) (Figure 3.d) consists of a steel rod welded on three

floors of four knives with a special form. From one floor to another settlement knife is offset

by an angle of 300, so the knives to ensure the entire circumference, which provide a

complete cleaning wall tubing

Cleaner requires guidance is provided by four curved blades welded to the bottom of

the plunger body.

a ) b) c)

Fig. 4. Connectors, cables and wires

a)-fixed connection cable; b)- removable for cable connection; c)- removable connector for wire.

In Figure 4 presents the cable connections. From the point of view of the attachment of

the cable or wire is distinguished these types of connections:

a) fixed connection cable diameter 12 ... 18 mm (fig. 4 .. a). It is constructed from a piece of steel pipe which is threaded for screwing the bottom heavy stick, and the upper and

lower diameter is provided on the outside with circular grooves to be caught in case

there Corunca probe . Inside the connector has a cylindrical hole that is half the length,

and the other half is conical. For this type of connection cable can not be removed

except by cutting;


48

b) Connection removable cable diameter 7 ... 8 mm (fig. 4 .. b) does not require cutting cable disassembly. Inside the steel body is fixed to a steel composed of two pieces and

a galvanized metal sheath, which assembles over the cable node.

c) Removable connection wires 1.7 ... 2.2 mm is shown in Figure 4.c. In this connection, the head bends the wire around a pin having a diameter of 8 mm and a length of 20

mm. The free end of the wire head rotates several times around the wire. This knot

with a pin is retained until entering the coupling body.

Pistonare downspouts and dewaxing (Figure 5) is mounted at the head of the probe rash

introduction cleaners of paraffin. This casing has a diameter of 31/2 - 4 m and the length of

the downpipe 12, the upper part has a socket in which is screwed a particular sealing cap, and

the lower part has a thread in which is screwed a flange connecting the upper valve head

eruption. The body casing at the bottom of a pipe welding 23/8 which is mounted in the drain

pipe in the basement that serves the oil escaping from the well tubing by ferries, in the top of

the device casing.

Special head seal from the top of the casing is called oil removal. It consists of a lower

body, an intermediate body and a cap inside the bodies are aflǎ rubber gaskets for sealing

cable and pressing rings (two pieces) made of bronze.

Tighten the cable seals by rotating the cap with levers that is Scheduled.

Fig.5 Pipe dewaxing

1-cup, 2-lower body, 3 rubber seals, 4-socket 23/8 ", 5-ring compression,

6-body casing, 7-spacer, 8-body intermediate

4.CONCLUSIONS

Research undertaken on cleaning oil pipelines and networks as for transport crude oil

and petroleum products shows that within them is deposited drilling mud and paraffin and

cerezima which reduces pipe diameter and fluid flow velocity In this context it is necessary,

periods of cleaning these pipes with solutions and special devices

REFERENCES

[1.] BranzanOvidiu,Studiulprelungiriidurabilitatiiconductelor de transport

produsepetroliere ,2007

[2.] LuerenichSren-

UntersuchungenzurBildungKorrosiverBelageinolgefeuertenCrasturbinen,Hachen 2009

[3.] Schutze,Michael-Conrosion and enviconmental degradation NewYork 2000


49

CHARACTERIZING THE BEHAVIOR OF THE LUBRICANT

FILMS USING MOLECULAR DYNAMICS SIMULATIONS

Lecturer Ph.D. Cristian PIRGHIE, Stefan cel Mare University of Suceava,

Department of Mechanics and Technology, [email protected]

Assistant lecturer Ph.D. Ana-Camelia PIRGHIE, Stefan cel Mare University of

Suceava, Department of Mechanics and Technology, [email protected]

Abstract. When large industries develop products, the size and complexity of it impose

major challenges. This is the case for nano-devices, which are widely present in engineering

applications. As we know, in nanotechnology the matter must be manipulated at this miniscule

scale, the nanotechnology playing by different rules. The laws we know for large systems do not

necessarily apply at the nanoscale. Doubtless, the nanotechnology developments are connected to

a correct understanding of micro- and nanotribological processes. The components used in micro-

and nanostructures are light and operate under loads, and generally lubricated with molecularly

thin films. The tribology field is evident interdisciplinary, involving scientists from many different

disciplines, including physicists, chemists, engineers, and biologists. Development of the

micro/nanotribology field has contributed to the fundamental understanding of friction and wear

processes, these being dependent on the surface interactions. The experiment results for lubricant

nanofilms have highlighted interesting properties, their comprehensive analysis being possible by

computer simulations, in the last decade an exponential increase in computing power simulation

techniques taking place. Giving the operating conditions lubricants are subjected to in practical

applications, in this paper the thin-film lubrication at sliding surfaces is considered. In this

respect, we are investigated confined nanofilms, between two walls, thin film lubrication being

simulated using non-equilibrium molecular dynamics. To impose shear on the fluid, the upper wall

is moved at different constant sliding velocities, in the same time supporting different constant

loads. Therefore, we provide a clearer understanding of the influence of molecular architecture on

mef - parametrii de discretizare a structurilorfiabilitate si durabilitate - fiability & durability...

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