UNIVERSITI TEKNOLOGI MARA FAKULTI KEJURUTERAAN KIMIA

PROCESS ENGINEERING LABORATORY 1(CPE465)

No. Title Allocated Marks (%) Marks1 Abstract/Summary 52 Introduction 103 Aims 54 Theory 105 Apparatus 56 Methodology/Procedure 107 Results 108 Calculations 109 Discussion 20

10 Conclusion 511 Recommendations 512 Reference / Appendix 5

TOTAL MARKS 100

Remarks:

Checked by:

---------------------------Date:

NAME : MUHAMAD BAIHAKHI BIN SHAMSUDIN STUDENT ID : 2014442906GROUP : EH2202AGROUP EXPERIMENT : 3

EXPERIMENT : FLOWMETER DEMONSTRATIONDATE PERFORMED : 28 APRIL 2015SEMESTER : 2PROGRAMME / CODE : EH220 / CPE465SUBMIT TO : PUAN DIYANAH BINTI KAMARUDIN

ABSTRACT

This experiment has been done to investigate and demonstrate the operation and

characteristics of three flow meter with different types including it accuracy and energy

losses. The Flow Meter Demonstration Unit was used as the apparatus in this experiment.

We need to identified three different types of flow meter contain or found in the unit at the

beginning of the experiment. Orifice meter, Venturi meter and Variable Rotameter were the

flow meters that placed in this unit. The Venturi and Orifice meter only can measured the

output which not linear with the flow rate, Q. The Variable rotameter was in the other hand.

The output which is directly proportional to the flow rate can measured by the variable

rotameter and no need to measure the pressure difference. The average timed flow rate, Q t

was calculated to be 10.85 l/min, the average venturi meter flow rate, Qv was calculated to

be 70.19 l/min, the average variable rotameter flow rate, Qr was calculated to be 12.50 l/min

and the average orifice plate flow rate, Qo was established to be approximately 76.76 l/min.

Thus, the average velocity had calculated was 0.34 m/s and the average velocity head was

7.59 mm.

Introduction

In various industrial plants, process of measuring the flow of liquids is critical needed in

the pipeline. In some operation or process, accuracy can make the difference between

making a profit or having a loss to the plant or company. Because of that, accuracy of the

flow measurements is very important. A inaccurate measurement of the liquids flow can also

cause a serious result and can cause a death.

Nowadays, there are a lot of liquid flow measurements instruments and the flow rate can be

determined inferentially by measuring the change in kinetic energy or liquid’s velocity with

this instruments. The pressure differential that is forcing the liquid through a pipe or conduit

will affect the liquid velocity. The pipe’s cross-sectional area is known and it is remains

constant and because of this the average velocity is an indication of the flow rate. The

relationship of the liquid’s flow rate in such cases is:

Q=V × A

SOLTEQ® Flowmeter Measurement Apparatus (Model: FM101) apparatus is

designed to operate together with a basic hydraulic bench or any water supply. It is to

familiarize the students with typical methods of flow measurement of an incompressible

fluid.

The flow measurement comparison is able to demonstrate by the apparatus by using a

orifice device, venture device and rotameter. Based on the flow comparison, we can

compare against the flow measurement of the hydraulics bench which can be either by

Volumetric or Gravimeteric Method. The two methods is chosen depending on the type of

hydraulics bench in use. A 90 degree elbow with pressure tappings before and after this

elbow is another features of the flow apparatus. These features purpose is to provide an

added function to this apparatus to allow students to calculate the total head loss and loss

coefficient when fluid flows through these devices.

In short, the following range of experiment to be carried out is allowed by the apparatus.

a) Direct comparison of flow measurement using venturi, orifice, rotameter and bench.

b) Determination of total head loss and loss coefficient of fluid flow through a 90 degree

elbow.

c) Comparison of pressure drop against each device.

Aims

1. To obtain the flow rate measurement by utilizing three basic types of flow

measuring techniques; rotameter, venturi meter and orifice meter.

2. To investigate the loss coefficient of fluid through 90 degree elbow.

THEORY

Three most common devices used to measure the flow rate in pipes or internal flow.

The three meters are orifice meter, Venturi meter, and rotameter. They operates with the

same principle which is the decrease in flow area in a pipe will causes an increase in velocity

that will cause decreasing in pressure. A correlation of the velocity with the pressure

difference provides a means of measuring the flow rate. By negligible the viscous effects and

under the assumption of a horizontal pipe, and with the application of the Bernoulli equation

between point (1) and (2), it gave:

Qideal=A2V 2=A22( p1−p2)ρ(1−β4)

Where, β = D2/D1. There is a head loss between (1) and (2) so the equation becomes:

Q=A1V 1=A2V 2

Rotameter

The rotameter is a flow meter in which a rotating free float is the indicating element.

Usually, a rotameter consists of a transparent tapered vertical tube through which

fluid flow upward. Within the tube is placed a freely suspended “float” of pump-bob

shape. The float rests on a stop at the bottom end when there is no flow.The float rises until

upward as it commences and buoyancy forces on it are balanced by

its weight. If the rate of flow is small, the float rises only a short distance and vice

versa. The points of equilibrium can be noted as a function of flow rate. With a

well-calibrated marked glass tube, the level of the float becomes a direct measure

of flow rate.

Orifice meter

Orifice meter is constructed by inserting a flat plate with a hole between two flanges

of a pipe. The geometry of the orifice meter is simple, low in cost and easy to install or

replace. The primary disadvantages of this meter are its limited capacity and the high

permanent head loss.

Pressure taps for orifices may be placed in several locations as shown in Figure 4.1.

Figure 4.1: Typical Orifice Meter

Venturi meter

Generally, the venture meter are made from castings and machined. This is to close

tolerances to duplicate the performance of the standard design. The Venturi meter are

expensive, heavy and bulky. Excellent pressure recovery is form as the conical diffuser

section downstream from the throat. The diagram of Venturi meter is shown in the Figure 4.2

below.

Figure 4.2: Diagram of Venturi meter

Applications of the Bernoulli equation yield the following result, which applies for both the

Venturi meter and the Orifice plate.

Bernoulli equation:

P1 + V12 + Z1 = P2 + V2

2 + Z2

ρg 2g ρg 2g

Z1=Z2

P1 + V12 = P2 + V2

2

ρg 2g ρg 2g

P1-P2 = V22 -V 1

2 ------------(1)

ρg 2g

from: Q1=Q2

A1V1=A2V2

V1=A2V2 ------------(2)

A1

(2) in (1) :

PI-P2 = V22 -(A 2V2/A1)2

ρg 2g

so;

V22 [1-(A 2/A1) 2 ] = ΔP

2g ρg

V2= 1 . ( 2ΔP) ---------------(3)

[1-(A2/A1)²] ρ

Q = CdA2V2 ---------------------(4)

(3) in (4) ;

flow rate, Qv = CdA2 . ( 2∆P)

[1-(A2/A1)²] p

where (2∆p) = (2g∆h)

p

where;

∆h : head difference in meter (m) from the manometer readings for the appropriate meter

g : acceleration due to gravity (m/s2)

Cd: discharge coefficient for meter

A1 : area of the test pipe upstream of the meter (m2)

A2 : throat area of the meter (m2)

It is necessary to use of discharge coefficient, Cd because of the simplifying

assumptions made when applying the Bernoulli equations. From this experiment, values of

this coefficient are determined. The assumed values used in the software are:

Venturi meter Cd = 0.98

Orifice plate Cd =0.63

The energy loss that occurs in a pipe fitting (so-called secondary loss) is commonly

expressed in term of e head loss (h, meters), and can be determined from the manometer

readings. For this experiment, head losses will be compared against the square of the flow

rate used. In addition, pressure loss for venturi and variable area flowmeter are low and for

orifice meter is medium.

APPARATUS

General Start-up Procedures

The Flowmeter Measurement Apparatus (Model: FM 101) is supplied ready for use

and only requires connection to the Hydraulic Bench (Model: FM 110) as follows:

a) The apparatus was placed on top of a suitable hydraulic bench.

b) The apparatus was level on the bench top.

c) The hydraulic coupling was connected to the outlet supply of the hydraulic bench.

d) The discharge connect of the flow apparatus hose was connected to the collection

tank of the hydraulic bench.

e) The apparatus was ready to be started.

Starting up the Apparatus:

1. The flow control valve of hydraulic bench was fully closed and the

discharge valve was fully opened.

2. Before starting up system, the discharge hose was ensured properly directed to

volumetric tank of fibreglass. Also the volumetric tank

drain valve was ensured that left OPEN to allow flow discharge back into sump tank.

3. Once step (b) was confirmed, the pump supply was start up from hydraulic bench.

The bench valve was opened slowly. At this point, water flowing from

hydraulic bench through to the flow apparatus and discharge through into

the volumetric tank of hydraulic bench and then drained back into sump

tank of hydraulic bench can be seen.

4. The flow control valve was proceeded to fully open. When the flow in the pipe is

steady and there is no trapped bubble, the bench valve was started to close to

reduce the flow to the maximum measurable flow rate.

5. The water level in the manometer board can be seen began to display

different level of water heights. (If the water level in the manometer board

is too high where it is out of visible point, adjust the water level by using

the staddle valve. With the maximum measurable flow rate, retain

maximum readings on manometer).

6. At this point, the flow was slowly reduced by controlling the flow discharge valve

of apparatus and this discharge valve might closed totally.

7. The water level in the manometer board can be seen

began to level into a straight level. This level maybe at the lower or maybe

at the higher end of the manometer board range. (Take note that the pump

from the hydraulic bench is at this time, still supplying water at a certain

pressure in the system).

8. The glass tube or plastic transfer tube has been watched out for “Trapped Bubbles”. If

bubbles present, it will remove remove from the system for better

accuracy. To do this, either slowly “press the plastic tube to push

the bubbles up or lightly “tab” the glass tube to release the bubbles

upwards

Demonstration of the operation and characteristic of three different basic types of

flowmeter

1. The apparatus was placed on bench, inlet pipe was connected to bench supply and outlet

pipe was connected into volumetric tank.

2. With the bench valve fully closed and the discharge valve fully opened,

the pump supply was started up from hydraulic bench.

3. The bench valve was opened slowly until it is fully opened.

4. When the flow in the pipe is steady and there is no trapped bubble,

the bench valve was started to close to reduce the flow to the maximum measurable flow

rate.

5. By using the air bleed screw, water level in the manometer board was adjusted.

The maximum readings was retained on manometers with the maximum measurable flow

rate.

6. The readings on manometers (A - J), rotameter was noted and flow rate was measured..

7. Step 6 was repeated for different flow rates. The flow rates can be adjusted by

utilizing both bench valve and discharge valve.

8. To demonstrate similar flow rates at different system static pressures, bench and flow

control valve was adjusted together. Manometer levels was adjusting as required.

Determination of the loss coefficient when fluid flows through a 90 degree elbow

1. The apparatus was placed on bench, inlet pipe was connected to bench supply and

outlet pipe was connected into volumetric tank.

2. With the bench valve fully closed and the discharge valve fully opened,

the pump supply was started up from hydraulic bench.

3. The bench valve was opened slowly until it is fully opened.

4. When the flow in the pipe is steady and there is no trapped bubble,

the bench valve was started to close to reduce the flow to the maximum measurable flow

rate.

5. By using the air bleed screw, water level in the manometer board was adjusted.

The maximum readings was retained on manometers with the maximum measurable flow

rate.

6. Readings on manometers (I and J) was noted and flow rate was measured.

7. Step 6 was repeated for different flow rates. The flow rates can be adjusted by

utilizing both bench valve and discharge valve.

8. The tables was completed.

9. Graph Δh against Vs2/2g for 90 degree elbow was plotted to determine the coefficient

of losses.

Calculation

For rotameter flowrate = 5 l/min

Venturi flow rate,

q = Cd× At ×(1-(At/A1¿2 ¿−1 /2[2g(ha-hc)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.240- 0.230)¿1 /2×1000 l/ 1/60 min

q = 29.44 l/min

For rotameter flowrate = 10 l/min

Venturi flow rate,

q = Cd× At ×(1-(At/A1¿2 ¿−1 /2[2g(ha-hc)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.276- 0.234)¿1 /2×1000 l/ 1/60 min

q = 60.32 l/min

For rotameter flowrate = 15 l/min

Venturi flow rate,

q = Cd× At ×(1-(At/A1¿2 ¿−1 /2[2g(ha-hc)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.284- 0.210)¿1 /2×1000 l/ 1/60 min

q = 80.07 l/min

For rotameter flowrate = 20 l/min

Venturi flow rate,

q = Cd× At ×(1-(At/A1¿2 ¿−1 /2[2g(ha-hc)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.335- 0.193)¿1 /2×1000 l/ 1/60 min

q = 110.92 l/min

For orifice flowrate = 5 l/min

q = Cd× At ×(1-(At/A7¿2 ¿−1 /2[2g(hg-hh)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.240- 0.228)¿1 /2×1000 l/ 1/60 min

q = 32.24 l/min

For orifice flowrate = 10 l/min

q = Cd× At ×(1-(At/A7¿2 ¿−1 /2[2g(hg-hh)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.264- 0.218)¿1 /2×1000 l/ 1/60 min

q = 63.13 l/min

For orifice flowrate = 15 l/min

q = Cd× At ×(1-(At/A7¿2 ¿−1 /2[2g(hg-hh)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.267- 0.162)¿1 /2×1000 l/ 1/60 min

q = 75.18 l/min

For orifice flowrate = 20 l/min

q = Cd× At ×(1-(At/A7¿2 ¿−1 /2[2g(hg-hh)¿1 /2

q = 0.98(2.011× 10−4)[1-((2.011× 10−4)/( 5.309×10−4))¿−1/2[ 2(9.81)(0.305- 0.090)¿1 /2×1000 l/ 1/60 min

q = 136.49 l/min

Volume(L) Time (min)

Flowrate, Q (L/min)

Differential Piezometer Head, (mm) ( elbow hi-hj)

V(m/s)

v2

2g(mm)

3 0.58 5.17 2 0.16 1.30 3 0.40 7.50 4 0.24 2.94 3 0.28 10.71 6 0.34 5.89 3 0.15 20.00 9 0.63 20.23

The minimum flowrate,Q = 5.17 l/min = 8.62× 10−5 m3/s

Velocity of flow in pipe (diameter= 26 mm)

V= 8.62× 10−5 m3/s5.31× 10−4

= 0.16 m/s

V² = 1.30 mm2g

The minimum flowrate,Q = 7.50 l/min = 1.25× 10−4 m3/s

Velocity of flow in pipe (diameter= 26 mm)

V= 1.25× 10−4 m3/s5.31× 10−4

= 0.24 m/s

V² = 2.94 mm2g

The minimum flowrate,Q = 10.71 l/min = 1.79× 10−4 m3/s

Velocity of flow in pipe (diameter= 26 mm)

V= 1.79× 10−4 m3/s5.31× 10−4

= 0.34 m/s

V² = 5.89 mm2g

The minimum flowrate,Q = 20.00 l/min = 3.33× 10−4 m3/s

Velocity of flow in pipe (diameter= 26 mm)

V= 3.33× 10−4 m3/s5.31× 10−4

= 0.63 m/s

V² = 20.23 mm2g

Graph of differential piezometer head against velocity

1 2 3 40

1

2

3

4

5

6

7

8

9

10

velocity head (mm)

piez

omet

er h

ead

(mm

)

DISCUSSIONS

Flow meter demonstration is to demonstrate three different types of flow meter which

are variable rotameter, venturi meter, orifice plate meter. From the reading taken, we can

calculate variable rotameter flow rate, orifice plate flow rate, venture meter flow rate and the

head velocity.

Based on these experiments, we can see the characteristic of three different types of

flow meter which is venturi meter, orifice meter, rotameter and their operations. During these

experiments, we also record all the readings and from the values we can see which one of

the flow meter give the accurate value.

After these experiments have been conducted, we are able to determine the value of

flow rate of three flowmeter. Based on the results from this experiment, the average variable

flow rate for rotameter is 12.50 l/min, for venturi meter is 70.19 l/min and 76.76 l/min for

orifice flowmeter.

Theoretically, venturi meter is a more accurate than orifice and variable rotameter. If

the result different from the theoretical, there are some error occurs. One of the major factors

that affect the readings is the bubble in pipeline. Other than that, parallax error which is the

position of eyes during taken the manometer reading. If eyes is not perpendicular during

reading the scale, error occur during the reading taken. The apparatus is also need to

improve as along the manometer, it needs to have more calibration to get more accurate

reading. Taking the reading will be more accurate if we do not to evaluate the reading

manually, it is better to have its own pressure transmitter, so that the reading shown is

sharply accurate. The venturi meter is the precise device in measuring the flow rate of any

fluid as it has the diverged portion that increases the velocity and reduces the friction loss.

In general, the orifice plate has the inherent advantage of being easy and inexpensive

to replace,low cost mantainance ,however the initial installation may be costly due to the

requirement of special orifice-plate flanges containing pressure taps. The advantage of all is

that it has no moving parts and the differential pressure sensor can be removed and

replaced, if any broke down happen, without shutting down the process. The advantages of

the venturi meter over the orifice plate are its capacity to handle more flow while imposing

less permanent pressure loss on the system. Other advantages are its ability to be used with

fluid containing of relatively high percentage entailer solids and its greater accuracy over a

wider flow rate range.

Conclusion

As a conclusion, we can say that the most accurate flow meter is a venturi meter. Based

on theory the venturi meter is the precise device in measuring the flow rate of any

fluid as it has the diverged portion that increases the velocity and reduces the friction

loss. By utilizing three basic types of flow measuring techniques; rotameter, venturi

meter and orifice meter, the flow rate measurement is successfully obtained. We

also successfully investigated the Loss coefficient of fluid through 90 degree elbow.

Based on this experiment, we determine that the flow rate % error for the

orifice meter is lower than % error venturi meter. From the theory, the more

efficiency of flow meter has a less flow rate % error.

Recommendation

1. Students must run the experiment after fully understand the unit and procedures.

2. It is important to drain all water from the apparatus when not in use. The apparatus

should be stored properly to prevent damage.

3. The apparatus should not be exposed to any shock and stresses.

4. Any manometer tube, which does not fill with water or slow fill, indicates that tapping

or connection of the manometer is blocked. To remove the obstacle, disconnect the

flexible connection tube and blow through.

5. Students should wear protective clothing, shoes, helmet and goggles throughout the

laboratory session.

References

1. Bruce R. Munson, Donald F. Young, Theodore H. Okiishi, Fundamental of Fluid

Mechanics, Pipe Flow Rate Measurement, 5th Edition, (2006), John Wiley & Sons,

Inc.

2. K.L. Kumar, “Engineering Fluid Mechanics”, 1st Edition, (1976), S. Chand & Company

Ltd.

3. Robert A. Granger, “Experiments in Fluid Mechanics”, TheVenturi and Orifice Meters,

1st Edition, (1988), Holt, Rinehart and Winston, Inc.

4. https://www.coursehero.com/file/8491162/Flowmeter-Demonstration-full/

5. http://www.engineeringtoolbox.com/flow-meters-d_493.html