numerical simulation on thermodynamics performance in the...

Research ArticleNumerical Simulation on Thermodynamics Performance in theFireproof Sealing by Finite Element Analysis

Shuai Gao123 Guoqing Zhu 123 Yunji Gao123 Guoqiang Chai123 and Jinju Zhou123

1Key Laboratory of Fire Protection of Urban Underground Space in Jiangsu Province China University of Mining and TechnologyXuzhou 221116 Jiangsu China2School of Safety Engineering China University of Mining and Technology Xuzhou 221116 Jiangsu China3Fire Research Institute China University of Mining and Technology Xuzhou 221116 Jiangsu China

Correspondence should be addressed to Guoqing Zhu zgq119xzcumteducn

Received 30 March 2019 Accepted 28 May 2019 Published 19 June 2019

Guest Editor Dong Wang

Copyright copy 2019 Shuai Gao et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In this paper the finite element analysis was firstly employed to investigate the thermal analysis on two fireproof sealing modelswith ANSYS software under HC standard temperature-time condition Themain thermal parameters were analyzed and obtainedincluding temperature field thermal flux and thermal gradient After comparing the two fireproof sealing models the majorconclusions are summarized as follows In terms of temperature field the temperature on the left side of the first model ranges from60 to 524∘C in In contrast the highest temperature on the left side of the second model eventually reaches below 151∘C Moreoverthe vectors of thermal gradient in the first model are compared with the second model and the temperature gradient disturbanceis more obvious in the second fireproof sealing model which is better to slow down temperature spreading The accelerated speedof E1 and G1 is 00096

∘Cs and 00619∘Cs partly which are far more than C2 and F2 with values of 00028∘Cs and 00078∘Csrespectively In a word the performance of the first fireproof sealing model is inferior to the second fireproof sealing model Theconclusions of the study are meaningful to improve the thermodynamic performance of the fireproof sealing in the converterstation

1 Introduction

Converter station is an important element in High VoltageDirect Current (HVDC) transmission system which con-verts alternating current into direct current or converts directcurrent into alternating current and electricity is the blood ofindustry and daily life If a fire occurs at a converter stationthe converter station will fail in the fire which will resultin loss of business and service and endanger peoplersquos livesTherefore the fireproof performance of the fireproof sealingisolated from the converter transformer side and the valvehall side of the converter station is studied

Over the years a large number of scholars have donea deal of investigations on fire protection with numericalsimulation Raduca et al [1] used finite element method topresent the modeling and simulation of the thermal transferin the transformers from the high electric voltage stationsand the simulation of an optimal solution was obtained

regarding the correct usage of the transformers Piloto etal [2] investigated the thermal behavior of the unexposedsurface and the nodal internal layers in light steel framewith numerical simulations Jeyakumar et al [3] carried outnumerical simulations on Ag2SO4ZnO(ASZ) nanocompos-ite coating with steady-state thermal analysis using ANSYSto validate the output in the numerical approach and theresults obtained showed that ASZ nanocomposite coatingacted as an efficient thermal barrier coating for the exhaustmanifold thus increasing its reliability Liu et al [4] car-ried out some simulations and experiments about weld-ing processes of martensitic steel (RAFM steel) in three-dimensional finite element models by ANSYS software andthe temperature fields and stress fields from simulationswere contrasted with that from experiments respectivelyMittal and Greiner [5] constructed two-dimensional andthree-dimensional thermal models of a Nuclear AssuranceCorporation Legal Weight Truck (NAC-LWT) cask using the

HindawiMathematical Problems in EngineeringVolume 2019 Article ID 9593626 9 pageshttpsdoiorg10115520199593626

2 Mathematical Problems in Engineering

PATRAN commercial finite element package under normaland fire accident conditions Liu et al [6] analyzed firstlypotential fire scenarios relevant to a cable-stayed bridgecrossing the Yangtze River then the temperature distributionin key elements and the global structural behavior of thebridge under tanker truck fires were calculated by usinggeneral purpose finite element analysis software ANSYSMoreover numerical simulation results demonstrated thatcable-stayed bridge might collapse under some specific firescenarios Zhang [7] conducted a comprehensive modalanalysis of Z-shaped beam electrothermal microactuators forthe first time and both longitudinal and lateral vibrationswere taken into account to obtain the vibration equationsof the unique geometric feature a Z-shaped beam with ashuttle in the middle Zivkovic et al [8] investigated theinfluence of the boiler scale on the thermal stresses andstrains of the structure of hot water boilers with the finiteelementsmethod byANSYS software andmaximum thermalstresses appeared in the zone of the pipe-carrying wall ofthe first reversing chamber Tomecek [9] studied thermalresponse of steel columns with lost protection material andvarying amounts of missing protection when exposed tothe ASTME-119 furnace environment by a finite elementanalysis of heat transfer Moreover some scholars studied thethermodynamic problem and design of fireproof sealing andplugging in building under the fire conditions In additionChung et al [10] conducted a simulation on the developmentof a finite element model capable of representing a blast-resistant flexible window (flex-window) system developedby the Air Force Research Laboratory Airbase TechnologiesDivision (AFRLRXQ) Hatiegan and Raduca [11] conductedthe thermal analysis on the hydrogenerator stator windingand found that the insulation aging is influenced first by theenvironmental conditions and second by the speed increaseof the high temperature chemical reaction inmaterialsMore-over Cindea and Hatiegan [12] investigated the influence ofthe thermal field on X60 carbon steel components duringwelding in CO2 environment given that the heat source(electric arc) moves

Sun and Zhou [13] studied the thermal properties onnew fireproof sealing sheet with the principle of fireproofsealing and plugging in building and proposed the compositeapplications of fireproof sealing technical measures on thebasis of combining the engineering application Ro [14]investigated the designing of appropriate height of firewallsfor toluene and methanol outdoor storage tankrsquos pool fireaccidents with considering input variables such as thermalradiation orifice diameter and elevation and the result ofeffect distances was obtained

Fireproof sealing is widely employed to limit the scaleof fire in multistory building commercial building indus-trial building medical building and other types of publicbuildings However the experiment on fireproof sealing isdifficult to conduct to obtain the parameter of thermaland fire resistance In this paper the two fireproof sealingmodels are established by ANSYS which is the first timeto apply finite element analysis to the research of fireproofsealing and improve the effectiveness of the later experimentThus the numerical simulation of finite element analysis is

introduced to study the fire protection of firewall sealing wallin this paper Regarding finite element analysis mathematicalapproximation is applied to simulate a real physical system(geometric and load conditions) With simple and interactingelements a finite number of unknowns can be used toapproximate an infinitely unknown real system In this paperthe finite element analysis was employed to investigate thethermal parameters such as temperature field thermal fluxand thermal gradient When optimum effective combinationwith different materials was assumed for the model a goodapproach was achieved by the simple calculation model andthe fireproof sealing model was made of different materialwhich would enhance fire protection performance

2 Simulation Setup

21 Geometry Model and Material Parameters The typicalfireproof materials are selected for fireproof sealing modelswhich are widely applied in the market and have the goodfireproof performance Moreover the combination of variousfireproof materials can greatly improve the mechanical andfireproof performance of a high-quality fireproof materialIn addition two typical models are selected for simulationstudy in combination experiment to explore whether the fireprotection performance of various composite materials canbe improved using specific research methodsThus the mainfireproof materials are rock wool aluminum silicate needleblanket square steel fire retardant coating fire retardantmodule ALC board cement and fire suppression moduleWhen designing the fireproof sealing not only fire resistancebut also stress and explosion hazard are required and thethermodynamics should be considered firstly due to theimportance of thermal performance In this paper twodifferent types of combination of fire sealing were simulatedwith finite element analysis by ANSYS and the parameters ofthermal were achieved as the evaluation criteria to obtain theoptimum effective combination The finite element analysiscan be divided into three procedures Firstly the designatedmodel should be built and the materials properties areapplied in the models secondly the parameters of boundaryconditions are given and the forces with different conditionsare loaded lastly the data are obtained and analyzed to checkthe desired result after completing the simulation

The fireproof sealing comprising rock wool aluminumsilicate needle blanket square steel and ALC board with firesuppression module was selected as the simulative materialsof two models And then thermal parameters such asdensity specific heat capacity and heat conductivity wereset respectively in ANSYS software which could influencethe thermal field and the velocity of temperature conductionand the specific parameters of four materials are shown inTable 1 [15] The apparatus of four material modules wereshown separately in Figures 1(a) and 1(b) and the fire surfaceswere on the right side of two models On account of thethermal characteristic changing with fire spread the typeof analysis was selected as transient and three significantthermal parameters were chosen as different characteristicsin various temperature fields

Mathematical Problems in Engineering 3

Table 1 Different kinds of material properties

Material category Temperature (∘C) Thermal Conductivity(W(msdotK)) Specific Heat

(J(kgsdotK)) Density (kgm3)

Rock wool

0sim300 0039

150 750301sim500 0057501sim800 0134801sim1200 0197

Aluminum silicateneedle-punched blanket

0sim400 004396 900401sim800 0093

801sim1200 0147Square steel 0sim1200 50 460 7850ALC board 0sim1200 02 17821 500Fire suppression module 0sim1200 03 1600 103

Aluminum silicate needle-punchedblanket

Aluminum

needle-punchedblanket

Rock wool

Square steel

Squaresteel

Squaresteel

Fire surfacesilicate

ALC board

1

1

(a)

Aluminum silicateneedle-punched

blanket


blanket

Rock wool

Square steel

Fire surface

Fire suppressionmodule

(b)

Figure 1 The designing model of fireproof sealing

The differences of two fireproof sealing models werethe model shape and the initial fire surface Moreover thefireproof performance of different materials was exhibitedduring the simulation in this paper One fireproof sealingmodelwas shown in Figure 1(a) whichwasmade of four kindsof plates with 410 times 500 times 200mm and the T-shape was theshape of model in the front side In contrast to Figure 1(a)the other fireproof sealing model was shown in Figure 1(b)which also consisted of four kinds of plates with 290 times 350 times200mm however the shape of model was rectangle to ensureprotective sealing A three-dimensional finite element modelwas built by ANSYS software and then mesh was comparedinto 18 and 11 areas respectively Furthermore 10mm meshwas employed at every different kind and the total number ofmeshes were 46179 and 26360 partly to meet the accuracy ofcalculation results which were exhibited in Figure 3

22 Boundary and Temperature Conditions for Thermal Anal-ysis The fire surface of the first model is on the ALC boardand square steel in the right of first model and the fire surfaceof the second model is on the rock wool and fire suppressionin the right of first model The fire surface of the fireproof

sealing is one side and the two fireproof sealing modelshave the same initial loads Thus when evaluating the fireresistance of building components under liquid hydrocarbonfire conditions a hydrocarbon (HC) heating curve can beused for fire resistance testing and is suited with the case Forthe HC fires the temperature-time relationship in the fire testfurnace is expressed by

119879 = 108 (1 minus 0325119890minus0167119905 minus 0675119890minus25119905 + 1198790) (1)

where 119905 denotes the time of simulation experiment whoseunit is minutes (min) and T is the average temperature at thetime t which is measured in degrees Celsius (∘C) Moreover1198790 is the initial average temperature before the start of the testwhich is required to be 5∘C to 40∘C and the value of1198790 is 20∘Cin this simulation The standard temperature-time curve ofthe hydrocarbon (HC) fire is shown in Figure 2 The possibleapplication scenario of the fire temperature rise curve is theoil and gas fire at the converter station

23Thermal AnalysisModel In the thermal simulation solid8-node 70 elements were applied as element types as shown in


0 20 40 60 80 100 120 140 160 180 2000

200

400

600

800

1000

1200

1400

Time (min)HC

Tem

pera

ture

(∘C)

Figure 2 The curve of hydrocarbon (HC) temperature heating

Figure 3 To realize the accuracy of simulation the initial tem-perature was set to 20∘C as simulation ambient temperatureOn account of the temperature of models parameters rangingfrom 0 to 1200∘C thermodynamic propagations can workafter the thermodynamic properties of materials are 20∘CThe type of model contact is surface to surface in differentmaterials and the contact value between the contact surfaceand the target surface is 1000 which is coordinated withsimulation requirement

3 Results and Discussion

31 Temperature Field in Fireproof of Different MaterialsAccording to heat transfer if there is a temperature gradientinside the model the energy will transfer from the hightemperature zone to the low temperature zone which istransferred in the form of heat conduction

Heat conduction is subject to Fourier law that is theheat flow density of a place formed by heat conduction isproportional to the temperature gradient of the same placeat the same time in the nonuniform temperature field andits mathematical expression in the one-dimensional modeltemperature field is exhibited in [16]

11990210158401015840119909 = minus119896119889119879119889119909 (2)

where 11990210158401015840119909 is thermal flux 119889119879119889119909 is the temperaturegradient in the 119909 direction and 119896 is thermal conductivity

When there is no internal heat source the unsteadythermal conductivity differential equation of the three-dimensional model temperature field is as follows [17]

120597119879120597119905 = 120572(1205972119879

1205971199092 +12059721198791205971199102 +

12059721198791205971199112 ) (3)

It is demonstrated from Figure 4 that the distribution oftemperature has diverse spread trend in the two fireproofsealing models with different materials In Figures 4(a) and4(b) since the right sides of themodels are the fire surface the

two models have highest temperature point in common andfinally reach to 1100∘C Simultaneously Figure 4(a) indicatesthat the temperature conduction to the left is a gradient ofheat growth but the temperature trend irregularly transfersto low energy which is due to the law of the conservation ofenergy and the function of two fire surfaces [18] Ultimatelythe temperature on the left side of the first model rangesfrom 60 to 524∘C and the temperature of rock wool is above524∘C However the thermal performance of superstructureis superior to substructures which demonstrates that themodel widths can affect the thermal performance of fireproofsealing In contrast Figure 4(b) shows that the regularityof heat conduction is more obvious and the speed ofconduction is apparently slow which could meet the requiredapplication requirements Moreover the highest temperatureon the left side of the second model eventually reaches below151∘C and the temperature in different material could befundamentally stabilized in the controlled range

By comparing Figure 4(a) with Figure 4(b) the firstmodel is inferior to the second model in the temperaturefield and the second model is also an optimized choice interms of heat conduction In addition the heat conductionequation employed for the calculation of temperature atvarious sections of the model is in accord with the law ofthermodynamics

32 Heat Flux in the Fireproof Sealing The heat is mainlytransmitted by heat conduction for fireproof sealing in a firescenario and the heat flux is explained by Fourierrsquos law In theone-dimensional model the relation between heat flux 119879(119909)and the thermal conductivity 119896 is as follows [19]

120601119902 = minus119896119889119879 (119909)119889119909 (4)

Theminus sign indicates that the heat fluxmoves from thehigher temperature region to the lower temperature region

In the three-dimensional model the heat flux vectors aredecomposed into several components

120601119902 = minus119896(997888rarr119894 120597119879120597119909 + 997888rarr119895 120597119879120597119910 + 997888rarr119891 120597119879120597119911 ) (5)

Since the thermal field analysis in fireproof sealing is notconstant the analysis of heat flow is critical and thermal fluxin the fireproof sealing is shown in Figure 5 It is noted fromFigure 5 that the minimum value of the heat flux is far lessthan the maximum value in the fireproof sealing and themaximum value of heat flux substantially exists in the squaresteel which is due to high thermal conductivity in the squaresteel

Thermal flux is a vector parameter which illustrates thetrend of heat flow To show the best heat flow the vectorsof the thermal flux in the two fireproof sealing models aredemonstrated in Figure 6 In Figure 6(a) on account of thecombination of up and down heat the vectors of thermalflux accumulate in the connection between square steel andaluminum silicate needle-punched blanket by the fire sidewhich demonstrates that the heat of bottom right aluminumsilicate needle-punched blanket is dominated by the heat flux


ELEMENTS

(a)

ELEMENTS

(b)

Figure 3 The grid with finite elements of geometrical model

(AVG)

600983 176153 292207 408261 524316 64037 756425 872479 988533 110459

MNNODAL SOLUTION

STEP=1SUB =108TIME=10800TEMPRSYS=0SMN =600983SMX =110459

(a)

NODAL SOLUTION

(AVG)

32621 151219 269816 388414 507012 625609 744207 862805981402 1100

MN

MX


(b)

Figure 4 The distribution of the temperature in the fireproof sealing

105164 191162 382219 573276 764333 95539 114645 133750 152856 171962

NODAL SOLUTION

STEP=1SUB=108 TIME=10800TFSUM (AVG)RSYS=0SMN=105164 SMX=171962

(a)

NODAL SOLUTION

(AVG)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397

STEP=1SUB =108TIME=10800TFSUMRSYS=0SMN =323292SMX =14397

(b)

Figure 5 Thermal flux in the fireproof sealing


VECTOR

105164191162

382219573276

76433395539

114645133750

152856171962

STEP=1SUB =108TIME=10800TFNODE=36182SMN =105164SMX =171962

(a)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397

VECTOR

STEP=1SUB =108TIME=10800TF

(b)

Figure 6 Vectors of the thermal flux in the fireproof sealing

801129287624

57444786127

114809143492

1721742008565

229538258221

(AVG)

VECTOR

STEP=1SUB =108TIME=10800TGSUMNODE=39011SMN =801129SMX =258221

(a)

(AVG)

33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

NODAL SOLUTION

STEP=1SUB =108TIME=10800TGSUMRSYS=0SMN =33915SMX =355347

(b)

Figure 7 Distribution of the thermal gradient in the fireproof sealing

of the two models Moreover the maximum of heat fluxvector gathers on square steel commonly in Figures 6(a) and6(b) which is far more than the other materials With theheat flowing the phenomenon of the energy concentration isgradually evident the values of thermal flux are bigger andbigger with fast speed in the two fireproof sealing modelsof which the vector direction is from the high temperatureregion to the low temperature region

33 Thermal Gradient in Fireproof Sealing The thermal gra-dient is a significant thermal parameter in the two fireproofsealing models which can analyze where and what ratethe temperature changes most rapidly under environmentalconditions [20]

119866119903119886119889119879 = limΔ119899997888rarr0

(Δ119879Δ119899 ) = (120597119879120597119899 ) (6)

Here 119899 is the unit vector in the normal direction and 120597 isthe derivative of temperature in the 119899 direction

The thermal gradients are transient in the two fireproofsealing models and the variation of distribution is demon-strated in Figure 7 It is noted from Figure 7(a) that thetrend of thermal gradient is not uniform and is changed bythe different thermal material properties and the variationincreases rapidly at the junction of square steel and rockwool which is due to the thermal conductivity with greatgap between square and rockwool In contrast the minimumvalue of thermal gradient is on the left of Figure 7 tendingtoward zero which keeps away from the fire surface It isdemonstrated from Figure 7(a) that the highest value ofthermal gradient is in the aluminum silicate needle blanketand the highest factor intensity of thermal gradient is also inthe aluminum silicate needle blanket However the highestvalue of thermal gradient exists in the connection of rockwool and square steel and the thermal gradient of the second


801129287624

57444786127

114809143492

172174200856

229538258221

VECTOR

STEP=1SUB =108TIME=10800TGNODE=39011SMN =801129SMX =258221

(a)

VECTOR

STEP=1SUB =108TIME=10800TG

33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

(b)

Figure 8 Vectors of the thermal gradient in the fireproof sealing

0

200

400

600

800

1000

1200

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

A1 B1 C1 D1

E1 F1 H1 G1

(a)

0

200

400

600

800

1000

1200

A2 B2 C2 D2

E2 F2 G2 H2

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

(b)

Figure 9 Temperature distribution of different material element in different nodes (a) the first ldquoTrdquo shape model (b) the second rectanglemodel

fireproof sealing model is more regular the increase oftemperature gradient shows obvious gradient distribution asshown in Figure 7(b)

The vectors of thermal gradient in two fireproof sealingmodels are exhibited in Figure 8 Contrary to thermal fluxthe vector direction is from the low temperature region to thehigh temperature region Nevertheless the thermal gradientin differentmaterials has the phenomenon of the regular flowand the vector direction is in accord with the calculation ofthe thermal gradientwith heat flowHowever the intersectionof two heat flows results in the crossing of temperaturegradient vectors which affects the fire prevention effect of the

fireproof sealingMoreover the vectors of thermal gradient inFigure 8(a) are compared with the vectors of thermal gradientin Figure 8(b) and the temperature gradient disturbance ismore obvious in the second fireproof sealing model which isbetter to prevent the heat from spreading and slow down thepropagation

34 Temperature Field of VariousMaterials in Different NodesIt is noted from Figure 1 that the different element points areselected to analyze the temperature field of various materialsThereby temperature trend on selected points of variousmaterials is shown in Figure 9 It is noted from Figure 9(a)


that the temperature of the other nodes finally reached above400∘C except for the two points D1 and E1 and the F1 pointquickly rose to 1100∘C at 100s which is in fire surface tosupply the high thermal energy The temperatures of the A1G1 B1 and H1 point gradually increase and asymptoticallyattain the constant values after the rapid rise However thetemperature at point C1 tends to increase linearly whichdemonstrates the stable heat transfer in steel plate On thecontrary the temperatures at the points of D1 and E riseslowly which are lower than 200∘C due to the protectionof the thick protective layer at the two points of D1 andE1 It is demonstrated from Figure 9(a) that the thermalinsulation performance in different materials are diverseThe ALC board and aluminum silicate needle-punched blan-ket are better than square steel in the thermal insulationperformance

As shown in Figure 9(b) the temperature of differentnodes in the second model increases slowly NeverthelessA2 and D2 increase at a high rate of speed with a powerfunction growth trend After rapid growth the temperaturesgradually tend to a fixed value with the highest temperaturereaching 1050∘C In contrast the temperatures of B2 C2E2 F2 G2 and H2 grow slowly with a linear growth trendComparing the temperature trends of A2 D2 and otherpoints the difference of temperature between them is to450∘C which indicates that the fire resistance of aluminumsilicate needle blanket is better while the temperatures of C2and F2 near the left side of the model keep below 100∘C all thetime

In terms of node temperature the first model has a max-imum temperature of 1050∘C and a minimum temperatureof 128∘C the second model has a maximum temperatureof 908∘C and a minimum temperature of 56∘C In contrastthe speed of heat in the first fireproof sealing model issignificantly faster than the second model By comparing thetemperature of different nodes of two fireproof sealing mod-els the overall growth trend of the first model is faster thansecond model and the final temperature of the first model ishigher than the second model which shows that the secondmodel has better fire protection performance Comparedwith E1G1 and C2F2 the temperature of the second modelis lower than that of the first model and the advantage of thesecond model is obvious Moreover the accelerated speed ofE1 is 00096

∘Cs and the accelerated speed of G1 is 00619∘Cs

which is far more than the accelerated speed of C2 and F2whose values are 00028∘Cs and 00078∘Cs respectively Bycomparing the temperatures of different nodes the secondfireproof sealingmodel is superior to the first fireproof sealingmodel

The temperatures in various nodes have different trendsbecause of the different energy transfer of the material Theenergy formula and energy conversion formula are as follows

Energy conversation formula [21]

119876 = 119888120588VΔ119905 (7)

where 119888 is the specific heat capacity 120588 is density ] is volumeΔ119905 is temperature change and 119876 is the change in energy

4 Conclusion

In this paper the finite element analysis was employed toinvestigate the thermal analysis on twofireproof sealingmod-els with ANSYS software under HC standard temperature-time condition The main thermal parameters such astemperature field thermal flux and thermal gradient wereanalyzed and obtained After comparing two fireproof sealingmodels the main conclusions of this paper are summarizedas follows

In terms of temperature field the temperature conductionto the left is a gradient of heat growth but the temperaturetrend irregularly transfers from high energy to low energywhich is due to the law of the conservation of energy andthe function of two fire surfaces Moreover in the first modelthe temperature on the left side ranges from 60 to 524∘C andthe temperature of rock wool is above 524∘C In contrastthe highest temperature on the left side of the second modeleventually reaches below 151∘C In a word the first model isinferior to the second model in the temperature field and thesecond model is also an optimized choice in terms of heatconduction

The minimum value of the heat flux is far less thanthe maximum value in the fireproof sealing Moreover withthe heat flowing the vector direction is from the hightemperature region to the low temperature region and thephenomenon of energy concentration is gradually evidentNevertheless the vectors of thermal gradient in the firstmodel are compared with the vectors of thermal gradient inthe second model and the temperature gradient disturbanceis more obvious in the second fireproof sealing model whichis better to prevent the heat from spreading and slow downthe propagation

By comparing the temperature of different nodes of twofireproof sealing models the overall growth trend of the firstmodel is faster than the second model which shows thatthe second model has better fire protection performanceCompared with E1G1 and C2F2 the accelerated speed of E1is 00096∘Cs and the accelerated speed of G1 is 00619

∘Cswhich is far more than the accelerated speed of C2 and F2whose values are 00028∘Cs and 00078∘Cs respectivelyThetemperature of the secondmodel is lower than that of the firstmodel and the advantage of the second model is obvious

In summary the finite element analysis is firstly applied inthe fireproof sealing as a reference for experiments and thisstudy is helpful to improve the thermodynamic performanceof the fireproof sealing in the converter station In the nextresearch it is still necessary to investigate the factors of stressand the trend of stress and the different combination indifferent superior materials will be further studied

Data Availability

The data used to support the findings of this study areincluded within the article

Conflicts of Interest

The authors declare that they have no conflicts of interest


Acknowledgments

This work was supported by National Key Research andDevelopment Plan (Project No 2016YFC0802900) the Fun-damental Research Funds for the Central Universities (No2018BSCXC02) Postgraduate Research amp Practice Innova-tion Program of Jiangsu Province (No KYCX18 1914) andFire Fighting and Rescue Technology Key Laboratory ofMPSOpen Project (No KF201802)

References

[1] M Raduca C Hatiegan N Pop E Raduca and G GillichldquoFinite element analysis of heat transfer in transformersfrom high voltage stationsrdquo Journal of Thermal Analysis andCalorimetry vol 118 no 2 pp 1355ndash1360 2014

[2] P Piloto M Khetata and A Ramos Fire Performance of Non-Loadbearing Light Steel Framing Wall-Numerical and SimpleCalculation Methods 2017

[3] N Jeyakumar A C A Kayambu R Ramasubbu and BNarayanasamy ldquoThermal analysis of nanostructured aluminastabilized zirconia coating on exhaustmanifoldrdquo Energy SourcesPart A Recovery Utilization and Environmental Effects vol 41no 7 pp 1ndash12 2018

[4] S Liu J Sun F Wei and M Lu ldquoNumerical simulationand experimental research on temperature and stress fields inTIG welding for plate of RAFM steelrdquo Fusion Engineering andDesign vol 136 pp 690ndash693 2018

[5] K Mittal and M Greiner ldquoThermal analysis of a NAC-LWTcask under normal and fire accident conditionsrdquo in Proceedingsof the ASME 2012 Pressure Vessels and Piping Conference PVP2012 vol 7 pp 305ndash312 July 2012

[6] Y J Liu B Ning andYWang ldquoStudy on thermal and structuralbehavior of a cable-stayed bridge under potential tanker truckfiresrdquo Applied Mechanics and Materials vol 238 pp 684ndash6882012

[7] Z Zhang Y Yu and X Zhang ldquoTheoretical modal analysis andparameter study of Z-shaped electrothermal microactuatorsrdquoMicrosystem Technologies vol 24 no 7 pp 3149ndash3160 2018

[8] D Zivkovic DMilcicM Banic andPMilosavljevic ldquoThermo-mechanical finite element analysis of hot water boiler structurerdquoThermal Science vol 16 no Supplement 2 pp S387ndashS398 2012

[9] D V Tomecek and J A Milke ldquoA study of the effect of partialloss of protection on the fire resistance of steel columnsrdquo FireTechnology vol 29 no 1 pp 3ndash21 1993

[10] J H Chung G R Consolazio R J Dinan and S A RinehartldquoFinite-elementanalysis of fluid-structure interaction in a blast-resistant window systemrdquo Journal of Structural Engineering vol136 no 3 pp 297ndash306 2010

[11] CHatieganM RaducaD Frunzaverde E Raduca andN PopldquoThe modeling and simulation of the thermal analysis on thehydrogenerator stator winding insulationrdquo Journal of ThermalAnalysis Calorimetry vol 113 no 3 pp 1217ndash1221 2013

[12] L Cındea C Hatiegan N Pop et al ldquoThe influence of thermalfield in the electric arc welding of X60 carbon steel componentsin the CO 2 environmentrdquo Applied Thermal Engineering vol103 pp 1164ndash1175 2016

[13] Z Sun and Y Zhou ldquoDiscussion on fire-proof sealing technol-ogy and productrdquo Procedia Engineering vol 135 pp 644ndash6482016

[14] SM Ro YWChon IM Lee et al ldquoFirewall design for tolueneampmethanol outdoor storage tank in case of pool fire accidentsrdquoKorean Journal of Hazardous Materials vol 5 pp 1ndash9 2017

[15] T T Lie and R J Irwin ldquoMethod to calculate the fire resistanceof reinforced concrete columns with rectangular cross sectionrdquoACI Structural Journal vol 90 no 1 pp 52ndash60 1993

[16] I-S Liu ldquoOn Fourierrsquos law of heat conductionrdquo ContinuumMechanics andThermodynamics vol 2 no 4 pp 301ndash305 1990

[17] H D Baehr and K Stephan Heat Conduction and MassDiffusion 1998

[18] V L Morgunov ldquoCalorimeter energy calibration using theenergy conservation lawrdquo PramanamdashJournal of Physics vol 69no 6 pp 1097ndash1100 2007

[19] Z-yW Chunzhen Qiao and X Xiang ldquoExothermal transfer lawand calculation of one-dimensional steady state heat conduc-tion processrdquo Journal of North China Electric Power Universityvol 30 pp 50ndash53 2003

[20] M J Tholey M V Swain and N Thiel ldquoThermal gradientsand residual stresses in veneered Y-TZP frameworksrdquo DentalMaterials vol 27 no 11 pp 1102ndash1110 2011

[21] S Kasap andTDan ldquoThermal properties and thermal analysisrdquoSurveys in High Energy Physics pp 336ndash338385 2006

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PATRAN commercial finite element package under normaland fire accident conditions Liu et al [6] analyzed firstlypotential fire scenarios relevant to a cable-stayed bridgecrossing the Yangtze River then the temperature distributionin key elements and the global structural behavior of thebridge under tanker truck fires were calculated by usinggeneral purpose finite element analysis software ANSYSMoreover numerical simulation results demonstrated thatcable-stayed bridge might collapse under some specific firescenarios Zhang [7] conducted a comprehensive modalanalysis of Z-shaped beam electrothermal microactuators forthe first time and both longitudinal and lateral vibrationswere taken into account to obtain the vibration equationsof the unique geometric feature a Z-shaped beam with ashuttle in the middle Zivkovic et al [8] investigated theinfluence of the boiler scale on the thermal stresses andstrains of the structure of hot water boilers with the finiteelementsmethod byANSYS software andmaximum thermalstresses appeared in the zone of the pipe-carrying wall ofthe first reversing chamber Tomecek [9] studied thermalresponse of steel columns with lost protection material andvarying amounts of missing protection when exposed tothe ASTME-119 furnace environment by a finite elementanalysis of heat transfer Moreover some scholars studied thethermodynamic problem and design of fireproof sealing andplugging in building under the fire conditions In additionChung et al [10] conducted a simulation on the developmentof a finite element model capable of representing a blast-resistant flexible window (flex-window) system developedby the Air Force Research Laboratory Airbase TechnologiesDivision (AFRLRXQ) Hatiegan and Raduca [11] conductedthe thermal analysis on the hydrogenerator stator windingand found that the insulation aging is influenced first by theenvironmental conditions and second by the speed increaseof the high temperature chemical reaction inmaterialsMore-over Cindea and Hatiegan [12] investigated the influence ofthe thermal field on X60 carbon steel components duringwelding in CO2 environment given that the heat source(electric arc) moves

Sun and Zhou [13] studied the thermal properties onnew fireproof sealing sheet with the principle of fireproofsealing and plugging in building and proposed the compositeapplications of fireproof sealing technical measures on thebasis of combining the engineering application Ro [14]investigated the designing of appropriate height of firewallsfor toluene and methanol outdoor storage tankrsquos pool fireaccidents with considering input variables such as thermalradiation orifice diameter and elevation and the result ofeffect distances was obtained

Fireproof sealing is widely employed to limit the scaleof fire in multistory building commercial building indus-trial building medical building and other types of publicbuildings However the experiment on fireproof sealing isdifficult to conduct to obtain the parameter of thermaland fire resistance In this paper the two fireproof sealingmodels are established by ANSYS which is the first timeto apply finite element analysis to the research of fireproofsealing and improve the effectiveness of the later experimentThus the numerical simulation of finite element analysis is

introduced to study the fire protection of firewall sealing wallin this paper Regarding finite element analysis mathematicalapproximation is applied to simulate a real physical system(geometric and load conditions) With simple and interactingelements a finite number of unknowns can be used toapproximate an infinitely unknown real system In this paperthe finite element analysis was employed to investigate thethermal parameters such as temperature field thermal fluxand thermal gradient When optimum effective combinationwith different materials was assumed for the model a goodapproach was achieved by the simple calculation model andthe fireproof sealing model was made of different materialwhich would enhance fire protection performance

2 Simulation Setup

21 Geometry Model and Material Parameters The typicalfireproof materials are selected for fireproof sealing modelswhich are widely applied in the market and have the goodfireproof performance Moreover the combination of variousfireproof materials can greatly improve the mechanical andfireproof performance of a high-quality fireproof materialIn addition two typical models are selected for simulationstudy in combination experiment to explore whether the fireprotection performance of various composite materials canbe improved using specific research methodsThus the mainfireproof materials are rock wool aluminum silicate needleblanket square steel fire retardant coating fire retardantmodule ALC board cement and fire suppression moduleWhen designing the fireproof sealing not only fire resistancebut also stress and explosion hazard are required and thethermodynamics should be considered firstly due to theimportance of thermal performance In this paper twodifferent types of combination of fire sealing were simulatedwith finite element analysis by ANSYS and the parameters ofthermal were achieved as the evaluation criteria to obtain theoptimum effective combination The finite element analysiscan be divided into three procedures Firstly the designatedmodel should be built and the materials properties areapplied in the models secondly the parameters of boundaryconditions are given and the forces with different conditionsare loaded lastly the data are obtained and analyzed to checkthe desired result after completing the simulation

The fireproof sealing comprising rock wool aluminumsilicate needle blanket square steel and ALC board with firesuppression module was selected as the simulative materialsof two models And then thermal parameters such asdensity specific heat capacity and heat conductivity wereset respectively in ANSYS software which could influencethe thermal field and the velocity of temperature conductionand the specific parameters of four materials are shown inTable 1 [15] The apparatus of four material modules wereshown separately in Figures 1(a) and 1(b) and the fire surfaceswere on the right side of two models On account of thethermal characteristic changing with fire spread the typeof analysis was selected as transient and three significantthermal parameters were chosen as different characteristicsin various temperature fields





Rock wool

0sim300 0039

150 750301sim500 0057501sim800 0134801sim1200 0197


0sim400 004396 900401sim800 0093



Aluminum


Rock wool

Square steel

Squaresteel

Squaresteel


ALC board

1

1

(a)


blanket


blanket

Rock wool

Square steel

Fire surface


(b)









0 20 40 60 80 100 120 140 160 180 2000

200

400

600

800

1000

1200

1400

Time (min)HC

Tem

pera

ture

(∘C)






11990210158401015840119909 = minus119896119889119879119889119909 (2)



120597119879120597119905 = 120572(1205972119879

1205971199092 +12059721198791205971199102 +

12059721198791205971199112 ) (3)





120601119902 = minus119896119889119879 (119909)119889119909 (4)







ELEMENTS

(a)

ELEMENTS

(b)


(AVG)

600983 176153 292207 408261 524316 64037 756425 872479 988533 110459

MNNODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

32621 151219 269816 388414 507012 625609 744207 862805981402 1100

MN

MX


(b)


105164 191162 382219 573276 764333 95539 114645 133750 152856 171962

NODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397


(b)



VECTOR

105164191162

382219573276

76433395539

114645133750

152856171962


(a)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397

VECTOR


(b)


801129287624

57444786127

114809143492

1721742008565

229538258221

(AVG)

VECTOR


(a)

(AVG)

33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

NODAL SOLUTION


(b)




119866119903119886119889119879 = limΔ119899997888rarr0

(Δ119879Δ119899 ) = (120597119879120597119899 ) (6)




801129287624

57444786127

114809143492

172174200856

229538258221

VECTOR


(a)

VECTOR


33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

(b)


0

200

400

600

800

1000

1200

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

A1 B1 C1 D1

E1 F1 H1 G1

(a)

0

200

400

600

800

1000

1200

A2 B2 C2 D2

E2 F2 G2 H2

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

(b)














119876 = 119888120588VΔ119905 (7)


4 Conclusion







Data Availability





Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018












Rock wool

0sim300 0039

150 750301sim500 0057501sim800 0134801sim1200 0197


0sim400 004396 900401sim800 0093



Aluminum


Rock wool

Square steel

Squaresteel

Squaresteel


ALC board

1

1

(a)


blanket


blanket

Rock wool

Square steel

Fire surface


(b)









0 20 40 60 80 100 120 140 160 180 2000

200

400

600

800

1000

1200

1400

Time (min)HC

Tem

pera

ture

(∘C)






11990210158401015840119909 = minus119896119889119879119889119909 (2)



120597119879120597119905 = 120572(1205972119879

1205971199092 +12059721198791205971199102 +

12059721198791205971199112 ) (3)





120601119902 = minus119896119889119879 (119909)119889119909 (4)







ELEMENTS

(a)

ELEMENTS

(b)


(AVG)

600983 176153 292207 408261 524316 64037 756425 872479 988533 110459

MNNODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

32621 151219 269816 388414 507012 625609 744207 862805981402 1100

MN

MX


(b)


105164 191162 382219 573276 764333 95539 114645 133750 152856 171962

NODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397


(b)



VECTOR

105164191162

382219573276

76433395539

114645133750

152856171962


(a)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397

VECTOR


(b)


801129287624

57444786127

114809143492

1721742008565

229538258221

(AVG)

VECTOR


(a)

(AVG)

33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

NODAL SOLUTION


(b)




119866119903119886119889119879 = limΔ119899997888rarr0

(Δ119879Δ119899 ) = (120597119879120597119899 ) (6)




801129287624

57444786127

114809143492

172174200856

229538258221

VECTOR


(a)

VECTOR


33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

(b)


0

200

400

600

800

1000

1200

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

A1 B1 C1 D1

E1 F1 H1 G1

(a)

0

200

400

600

800

1000

1200

A2 B2 C2 D2

E2 F2 G2 H2

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

(b)














119876 = 119888120588VΔ119905 (7)


4 Conclusion







Data Availability





Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018









0 20 40 60 80 100 120 140 160 180 2000

200

400

600

800

1000

1200

1400

Time (min)HC

Tem

pera

ture

(∘C)






11990210158401015840119909 = minus119896119889119879119889119909 (2)



120597119879120597119905 = 120572(1205972119879

1205971199092 +12059721198791205971199102 +

12059721198791205971199112 ) (3)





120601119902 = minus119896119889119879 (119909)119889119909 (4)







ELEMENTS

(a)

ELEMENTS

(b)


(AVG)

600983 176153 292207 408261 524316 64037 756425 872479 988533 110459

MNNODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

32621 151219 269816 388414 507012 625609 744207 862805981402 1100

MN

MX


(b)


105164 191162 382219 573276 764333 95539 114645 133750 152856 171962

NODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397


(b)



VECTOR

105164191162

382219573276

76433395539

114645133750

152856171962


(a)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397

VECTOR


(b)


801129287624

57444786127

114809143492

1721742008565

229538258221

(AVG)

VECTOR


(a)

(AVG)

33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

NODAL SOLUTION


(b)




119866119903119886119889119879 = limΔ119899997888rarr0

(Δ119879Δ119899 ) = (120597119879120597119899 ) (6)




801129287624

57444786127

114809143492

172174200856

229538258221

VECTOR


(a)

VECTOR


33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

(b)


0

200

400

600

800

1000

1200

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

A1 B1 C1 D1

E1 F1 H1 G1

(a)

0

200

400

600

800

1000

1200

A2 B2 C2 D2

E2 F2 G2 H2

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

(b)














119876 = 119888120588VΔ119905 (7)


4 Conclusion







Data Availability





Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018









ELEMENTS

(a)

ELEMENTS

(b)


(AVG)

600983 176153 292207 408261 524316 64037 756425 872479 988533 110459

MNNODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

32621 151219 269816 388414 507012 625609 744207 862805981402 1100

MN

MX


(b)


105164 191162 382219 573276 764333 95539 114645 133750 152856 171962

NODAL SOLUTION


(a)

NODAL SOLUTION

(AVG)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397


(b)



VECTOR

105164191162

382219573276

76433395539

114645133750

152856171962


(a)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397

VECTOR


(b)


801129287624

57444786127

114809143492

1721742008565

229538258221

(AVG)

VECTOR


(a)

(AVG)

33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

NODAL SOLUTION


(b)




119866119903119886119889119879 = limΔ119899997888rarr0

(Δ119879Δ119899 ) = (120597119879120597119899 ) (6)




801129287624

57444786127

114809143492

172174200856

229538258221

VECTOR


(a)

VECTOR


33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

(b)


0

200

400

600

800

1000

1200

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

A1 B1 C1 D1

E1 F1 H1 G1

(a)

0

200

400

600

800

1000

1200

A2 B2 C2 D2

E2 F2 G2 H2

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

(b)














119876 = 119888120588VΔ119905 (7)


4 Conclusion







Data Availability





Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018









VECTOR

105164191162

382219573276

76433395539

114645133750

152856171962


(a)

323292 160254 320185 480115 640046 799977 959908 111984 127977 14397

VECTOR


(b)


801129287624

57444786127

114809143492

1721742008565

229538258221

(AVG)

VECTOR


(a)

(AVG)

33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

NODAL SOLUTION


(b)




119866119903119886119889119879 = limΔ119899997888rarr0

(Δ119879Δ119899 ) = (120597119879120597119899 ) (6)




801129287624

57444786127

114809143492

172174200856

229538258221

VECTOR


(a)

VECTOR


33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

(b)


0

200

400

600

800

1000

1200

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

A1 B1 C1 D1

E1 F1 H1 G1

(a)

0

200

400

600

800

1000

1200

A2 B2 C2 D2

E2 F2 G2 H2

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

(b)














119876 = 119888120588VΔ119905 (7)


4 Conclusion







Data Availability





Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018









801129287624

57444786127

114809143492

172174200856

229538258221

VECTOR


(a)

VECTOR


33915 395132 789924 118472 157951 19743 236909 276389 315868 355347

(b)


0

200

400

600

800

1000

1200

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

A1 B1 C1 D1

E1 F1 H1 G1

(a)

0

200

400

600

800

1000

1200

A2 B2 C2 D2

E2 F2 G2 H2

2000 4000 6000 8000 10000 120000Time (s)

Tem

pera

ture

(∘C)

(b)














119876 = 119888120588VΔ119905 (7)


4 Conclusion







Data Availability





Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018
















119876 = 119888120588VΔ119905 (7)


4 Conclusion







Data Availability





Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018









Acknowledgments


References





























Journal of












Journal of







Volume 2018






Volume 2018















Journal of












Journal of







Volume 2018






Volume 2018








numerical simulation on thermodynamics performance in the...

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