2018傳熱傳質(zhì)學(xué)年會(huì)集

學(xué)術(shù)會(huì) ，，，王志（理工大學(xué)能源與動(dòng)力CFD，（ , 摘要球床反應(yīng)堆球表面局部熱點(diǎn)的存在影響到反應(yīng)堆的安全，其形成與球尺度的冷卻劑動(dòng)的特點(diǎn)及其對(duì)對(duì)流換熱的影響球表面的時(shí)均溫度分布表明球表面存在穩(wěn)定的熱點(diǎn)或熱斑，NumericalysisoflocalflowandheattransferinaFCCfrompebblebedYAOQiang,GUOXue-yan,YANGFan,WANGZhi-(CFDlaboratory,schoolofenergyandpowerengineering,UniversityofShanghaiforScienceandTechnology,Shanghai200093)( , :Theexistenceofhotspotsonthesurfaceofpebblesinpebblereactorsaffectsthesafetyofthereactoranditsformationiscloselyrelatedtothelocalflowofcoolantatthepebblescale.Inordertoensuretheaccuracyandphysicalrealityofthesolution,thelargeeddysimulation(LES)methodandthefullystructuredgridareappliedtoconductthenumericalysisofthelocalflowandheattransferofthefacecenteredcubic(FCC)unitintheareacontactarrangementmode.Thecharacteristicsofunsteadyflowanditseffectonconvectiveheattransferareyzed.Thetime-averagedtemperaturedistributionindicatesthattherearestablehotspotsonthesurfaceofpebbles,anditisalsofoundthattheinstantaneoustemperaturetemperatureissignificantlyhigherthanthetime-averaged①基金項(xiàng)目：國(guó)家自然科學(xué)基金 :pebblebedreactor;FCC;LES;structuredgrid;area在高溫反應(yīng)堆（HTR）[1-4]中，氦氣作為冷卻劑，核嵌在石墨慢化劑中并可以維然而，該結(jié)構(gòu)可能會(huì)出現(xiàn)的局部熱點(diǎn)問(wèn)題，這可能會(huì)影響球的完整性[6]。因此，對(duì)（SC（BCC11方Fig.1pebblebedpackingmethodsandcontactmodesbetween球床內(nèi)曲面繞流的復(fù)雜性激起了很多研究人員的，LEE等[8]于2007年采用κ-ε湍流模型比較了不同球間間隙對(duì)流場(chǎng)分布的影響；YassinA.Hassan[9]2008BCC2014Y.M.Ferng，K.Y.Lin[10]BCC接觸兩種接觸方式的共軛模型模擬的結(jié)果進(jìn)行了分析比較；2012年shams等[11]人采用q-DNSFCC存在射流現(xiàn)象及速度場(chǎng)、溫度場(chǎng)分布的不對(duì)稱性；2017年[12]采用大渦模擬方法，結(jié)構(gòu)網(wǎng)格研究了BCC點(diǎn)接觸模型的流場(chǎng)和溫度場(chǎng)，通過(guò)與κ-ε湍流模型計(jì)算結(jié)果對(duì)比，慮到有限的計(jì)算資源和網(wǎng)格劃分的難度，大部分的研究都采用了RANS湍流模型以及非FCC2Fig.2calculation3部Fig.3contact如圖2所示，為了使研究區(qū)域免受效應(yīng)影響，計(jì)算模型采用8個(gè)FCC面接觸單元堆積而成，球直徑為60mm，接觸程度如圖3所示，c1，c2為球心，r1，r2為球半徑，p1，p2Lp1p2/Lc1c2=0.010.6mm。，采用速度，大小為2.11m/s，溫度為773K雷諾數(shù)為5615，出口采用壓力出口四周采用對(duì)稱邊界條件用來(lái)模擬反應(yīng)堆中遠(yuǎn)離壁面的區(qū)域球面材料為石墨，8317w/m21，1物性參數(shù)Tab.1physicalpropertyRANSLES中，通過(guò)采用一亞格子模型，主要有以下幾種模型：Smagorinsky-LilySmagorinsky-Lily模型、WALEWMLESSmagorinsky-Lily模型，其優(yōu)點(diǎn)在于具有一面接觸模型則更顯。結(jié)構(gòu)網(wǎng)格的劃分，如圖4所示。由于采用LES方法進(jìn)行數(shù)值計(jì)算，網(wǎng)格尺度要求比采用RANSFCC1054網(wǎng)Fig.4pebblebed等人[14]的Q-DNS數(shù)據(jù)進(jìn)行對(duì)比。如圖5所示。結(jié)果顯示，LES方法的計(jì)算結(jié)果基本處于5Fig.5Comparisonofresultsofthreecalculation為了避免受效應(yīng)的影響本文選擇對(duì)中心球5及周圍流場(chǎng)區(qū)（如圖6所示）6Fig.6Centerpebbleandsurroundingflowfield57（9、10圖8下面觀察低速區(qū)渦的分布情況。如圖11所示，在壁面與球面圍成區(qū)域以及中心流體區(qū)7Fig.7Slice8Fig.8Thestagnationandwakeregionofthesphericalcentral 9（上）和溫度分布（下Fig.9Instantaneousvelocity(top)andtemperaturedistributions 10（上）和溫度分布（下Fig.10Time-averagedvelocity(top)andtemperaturedistributions 11線Fig.11Instantaneousstreamlinechartsofsection如圖12所示，球面上面接觸位置有三種分別為面1、面2、面3，正對(duì)來(lái)流的球面表面0.5mm處的速度分布（圖13）可以明顯看到溫度，速度分布情況與流場(chǎng)中基本一致速區(qū)；ⅱ.在接觸面后沿存在明顯高溫區(qū)且分成兩部分呈對(duì)稱分布，面1、面3后沿高溫12三種面接觸位Fig.12Threeareacontact13（上）0.5mm（下Fig.13Instantaneoustemperaturedistributionsonthesurfaceofthecentralpebble(top)andinstantaneousvelocitydistributionsat0.5mmawayfromthesphere(bottom)14（上）0.5mm（下Fig.14Time-averagedtemperaturedistributionsonthesurfaceofthecentralpebble(top)andtime-averagedvelocitydistributionsat0.5mmawayfromthesphere(bottom)圖15球0.5mm處流場(chǎng)區(qū)域速度與溫度梯度夾角的時(shí)均值分Fig.15Thetime-meandistributionsoftheanglebetweenvelocityandtemperaturegradientintheflowfieldat0.5mmawayfromthefuelsphere1713線2不經(jīng)過(guò)接觸面。線2上的瞬時(shí)和時(shí)均溫度略有波動(dòng)，但溫差不大，12K以內(nèi)。13148K，326K，而且所取線還并過(guò)存在最高溫度的區(qū)域。這比Shams等人做的人工間隙模型獲得的平均球面溫32K16取線位Fig.16Thepositionsoftheextracted17分Fig.17Theinstantaneousandtime-meantemperaturedistributionsonthe[1]周云龍,寬,.200MW模塊式高溫氣冷反應(yīng)堆蒸汽發(fā)生器設(shè)計(jì)[J].核科學(xué)與工程,ZHOUYun-Long,CHENTing-Kuan,CHENXue-Jun.Designof200MWModularhightemperaturegascooledreactorgenerator[J].JournalofNuclearScienceandEngineering,1992(1):25-34[2].我國(guó)高溫氣冷堆的發(fā)展[J].核動(dòng)力工程,2000,21(1):39-WUZong-Xin.Developmentofhightemperaturegascooledreactorsin[J].NuclearPowerEngineering,2000,21(1):39-43[3],.高溫氣冷堆在我國(guó)的發(fā)展綜述[J].現(xiàn)代電力,2006,23(5):70-FUXiao-Ming,WANGJie.Overviewofdevelopmentofhightemperaturegascooledreactorsin[J].ModernElectricPower,2006,23(5):70-75[4],.模塊式高溫氣冷堆的安全特性[J].高技術(shù)通訊,1994(11):34-WUZong-Xin,XIAOHong-Cai.Safetycharacteristicsofmodularhightemperaturegascooledreactor[J].HighTechnologyLetters,1994(11):34-38JansevanRensburg,J.J.,Viljoen,C.,vanStaden,M.P.,2006.CFDmodelingofhightemperaturecooledreactors.In:ProceedingsofICAPP’06,Reno,NVUSA,PaperforfutureHTRconcepts,Jül-4275,Jülich,Forschungszentrum,GermanyOomsA.,2008.Pebbleflowinahightemperaturereactor.PhysicsofNuclearReactor.PNR-131-003.TUDelft,TheLeeJJ,ParkGC,KimKY,etal.Numericaltreatmentofpebblecontactintheflowandheattransferysisofapebblebedreactorcore[J].NuclearEngineering&Design,2007,237(22):2183-2196HassanYA.Largeeddysimulationinpebblebedgascooledcorereactors[J].NuclearEngineering&Design,2008,238(3):530-537FerngYM,LinKY.CFDinvestigationofthermal-hydrauliccharacteristicsinaPBRcoreusingdifferentcontacttreatmentsbetweenpebbles[J].AnnalsofNuclearEnergy,2014,72(5):156-165PartI:Flow(velocity)fieldysis[J].NuclearEngineering&Design,2013,263(1):473-,.球床反應(yīng)堆流動(dòng)與傳熱的CFD分析:球尺度[J].能源工程,2017(6):8-13JIANGXu,GUOXue-Yan.CFDysisonflowandheattransferinpebblebedreactor:pebblescale[J].EnergyEngineering,2017(6):8-13ShamsA,RoelofsF,KomenEMJ,E.Baglietto.Optimizationof