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1、燃煤鍋爐燃燒過程流場及溫度場數(shù)值模擬題目二○一三年六月畢業(yè)設計(論文)系別動力工程系專業(yè)班級環(huán)境工程班學生姓名指導教師摘要數(shù)值模擬是以電子計算機為手段,通過數(shù)值計算和圖像顯示的方法,達到對工程問題和物理問題乃至自然界各類問題研究的目的。課題涉及到三維燃燒過程,并帶有兩相流。綜合考慮,我選擇了目前應用比較廣泛的FLUENT軟件作為數(shù)值模擬的工具。本文對鍋爐爐膛計算域通過GAMBIT軟件構建三維框架結構,從而對其進行網格劃分,確定合適的數(shù)學物理模型,設置邊界條件,選用適當?shù)淖兞亢蛥?shù),對爐膛燃燒進行三維數(shù)值模擬,得出爐膛內流場與溫度場分布。最后經過簡單的處理,將模擬結果以圖片或圖表的形式進行
2、直觀的展示。通過對模擬結果的觀察分析得出合理的結論,并分析不足之處。改變燃盡風風速大小,選擇30m/s、40m/s、49m/s及60m/s三種燃盡風速,研究燃盡風風速對爐內混合特性和爐內溫度場的影響。結果表明:燃盡風口風速增大時,爐內氣流的旋轉強度隨之增強,燃盡風的穿透程度隨之加強,相對容易穿透到爐膛中心,從而使得煙氣與煤粉的混合加劇,有利于增加煤炭燃燒的效率;在一定條件下,隨著燃盡風速的增加,爐膛中心的高溫區(qū)域面積增加,而且相對集中;隨著燃盡風速的增加,鍋爐煙氣出口的溫度降低;燃盡風風速為49m/s時爐內燃燒狀況最佳。關鍵詞:流場;溫度場;數(shù)值模擬;燃盡風IINUMERICALSIMU
3、LATIONONFLOWFIELDANDTEMPERATUREFIELDOFTHECOMBUSTIONPROCESSINTHEFIREDPULVERIZED-COALBOILERAbstractNumericalsimulationuseselectroniccomputersasthemeans.Toachievethepurposeofengineeringproblemsandphysicalproblemsaswellasthenatureofvariousproblems,itusesthemethodofthenumericalcalculationandimageshows
4、.Thetopicrelatestothethree-dimensionalcombustionprocessandthetwo-phaseflow.Considered,IchosetheFLUENTasthetoolfornumericalsimulation.Inthispaper,establishingthethreedimensionalframeconstructionwithGAMBIT,carryingonthegriddivision,thenselectingtheappropriatemodelofmathematicsandphysicsandthesuitab
5、leparameterandthevariable,settinguptheboundarycondition,makingthree-dimensionalnumericalsimulationoffurnacecombustion,receivingthedistributionsofflowfieldandtemperaturefieldinthefurnace.Aftersimpleprocessing,wecanshowtheresultbymakingthepicturesordiagrams.Makingaconclusionfromtheresultsandfinding
6、outtheinadequaciesoftheresults.Changingthesizeofvelocityofoverfiredair,choose30,40,49and60meterspersecond,thendiscusswhatwillhappenaboutmixingcharacteristicsofthefurnaceandtemperaturefield.StudyresultsindicatethatAsburnoutairspeedincreases,therotationofthefurnaceairflowintensityincreases,andthede
7、greeofpenetrationstrengthincreases,it’seasytopenetrateintothecenterofthefurnacerelatively,sothatthemixtureoffluegasandcoalincreases,theincreasingefficiencyofcoalcombustionisalsoinfavor.Undercertainconditions,astheveloc