結(jié)霜工況下翅片管換熱器傳熱傳質(zhì)的數(shù)值模擬

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1、上海交通大學(xué)碩士學(xué)位論文結(jié)霜工況下翅片管換熱器傳熱傳質(zhì)的數(shù)值模擬姓名：劉小川申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：制冷與低溫工程指導(dǎo)教師：谷波20070101逐步增大，出口溫度和含濕量變化平緩。在實(shí)驗(yàn)研究的基礎(chǔ)上，得到了濕空氣的壓力分布和含濕量分布。將模擬所得結(jié)果與實(shí)驗(yàn)數(shù)據(jù)進(jìn)行了對(duì)比，結(jié)果表明，模擬結(jié)果與實(shí)驗(yàn)數(shù)據(jù)變化趨勢(shì)相同，模擬結(jié)果與實(shí)驗(yàn)數(shù)據(jù)吻合較好。本文所建立的翅片管換熱器結(jié)霜模型得到了一個(gè)很好的模擬結(jié)果，此模型為國(guó)內(nèi)翅片管換熱器結(jié)霜模擬和其他設(shè)備、部件的結(jié)霜模擬介紹了一個(gè)全新的方法，為同類的結(jié)霜模型搭建了一個(gè)良好的平臺(tái)。模型加深了我們對(duì)翅片管換熱器干工況、結(jié)露工況和結(jié)霜

2、工況的理解，也加深了我們對(duì)如何模擬這些工況的認(rèn)識(shí)。但模型仍有不足，還需要改進(jìn)。關(guān)鍵詞：翅片管式換熱器結(jié)霜模擬VINumericalsimulationonheatandmasstransferoffrostformationonfinnedtubeheatexchangerABSTRACTFinnedtubeheatexchangersareextensivelyemployedinvariousindustrialapplications.Theyarequitecompact,lightlyweight,andcharacterizedbyarelative

3、lylowcostfabrication.Acomprehensiveunderstandingontheperformanceofheatandmasstransferoffinnedtubeheatexchangersisofprimeimportancetooptimizethedesignofheatexchangersforrefrigerationandairconditioningapplications.Frostformationonfinnedtubeheatexchangeroccurswidely.Whenmoistaircomesinc

4、ontactwithcoldheatexchangersurfacewhosetemperatureisbelowfreezingpoint,frostingoccurs.Thevaporoftheairbecomesfrostandthefroststickstothesurfaceoftheheatexchanger.Thefrostactsnotonlyasathermalinsulatorbetweenthesurfaceandthehumidambientair,butalsosignificantlyreducestheperformanceofth

5、eheatexchanger,sincetheairpassagesbecomenarrowerandpressuredropgeneratedbecomeshigher.Withtimegoesby,thethicknessofthefrostlayergrows.Inaddition,inordertoensurethedefrostingperiodoffinnedtubeheatexchanger,itisnecessarytounderstandthecharacteristicsoffrostformationdeeply.Asmallunitoff

6、innedtubeheatexchangerisstudied.Fromthesimulationresultsofthemodelofsmallunit,thesimulationperformanceofwholefinnedtubeheatexchangercanbeknown.Thecontinuous,momentum,energyandgridupdatingequationsoffrostformationonfinnedtubeheatexchangerweredescribed.。Usingnumericalmethod,thefrostacc

7、umulationquantityandheattransfercapacityofevaporatorsarepredicted,whichissimplifiedtoaquasi-stableproblemforconvenience.IneverytimesteptheprocessisconsideredtobestableandtheobtainedVIIdata,thefrostthicknessandthetemperatureofthefrostsurfaceareusedastheboundaryconditionsinthenexttimes

8、tep.Accordin