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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(shè)計(論文)系別動力工程系專業(yè)班級環(huán)境工程班學(xué)生姓名指導(dǎo)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(yīng)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(gòu)建三維框架結(jié)構(gòu),從而對其進行網(wǎng)格劃分,確定合適的數(shù)學(xué)物理模型,設(shè)置邊界條件,選用適當(dāng)?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(nèi)流場與溫度
2、場分布。最后經(jīng)過簡單的處理,將模擬結(jié)果以圖片或圖表的形式進行直觀的展示。通過對模擬結(jié)果的觀察分析得出合理的結(jié)論,并分析不足之處。改變?nèi)急M風(fēng)風(fēng)速大小,選擇30m/s、40m/s、49m/s及60m/s三種燃盡風(fēng)速,研究燃盡風(fēng)風(fēng)速對爐內(nèi)混合特性和爐內(nèi)溫度場的影響。結(jié)果表明:燃盡風(fēng)口風(fēng)速增大時,爐內(nèi)氣流的旋轉(zhuǎn)強度隨之增強,燃盡風(fēng)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(fēng)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(fēng)速的增加,鍋爐煙氣出口的
3、溫度降低;燃盡風(fēng)風(fēng)速為49m/s時爐內(nèi)燃燒狀況最佳。關(guān)鍵詞:流場;溫度場;數(shù)值模擬;燃盡風(fēng)IINUMERICALSIMULATIONONFLOWFIELDANDTEMPERATUREFIELDOFTHECOMBUSTIONPROCESSINTHEFIREDPULVERIZED-COALBOILERAbstractNumericalsimulationuseselectroniccomputersasthemeans.Toachievethepurposeofengineeringproblemsandphysicalproble
4、msaswellasthenatureofvariousproblems,itusesthemethodofthenumericalcalculationandimageshows.Thetopicrelatestothethree-dimensionalcombustionprocessandthetwo-phaseflow.Considered,IchosetheFLUENTasthetoolfornumericalsimulation.Inthispaper,establishingthethreedimensionalf
5、rameconstructionwithGAMBIT,carryingonthegriddivision,thenselectingtheappropriatemodelofmathematicsandphysicsandthesuitableparameterandthevariable,settinguptheboundarycondition,makingthree-dimensionalnumericalsimulationoffurnacecombustion,receivingthedistributionsoffl
6、owfieldandtemperaturefieldinthefurnace.Aftersimpleprocessing,wecanshowtheresultbymakingthepicturesordiagrams.Makingaconclusionfromtheresultsandfindingouttheinadequaciesoftheresults.Changingthesizeofvelocityofoverfiredair,choose30,40,49and60meterspersecond,thendiscuss
7、whatwillhappenaboutmixingcharacteristicsofthefurnaceandtemperaturefield.StudyresultsindicatethatAsburnoutairspeedincreases,therotationofthefurnaceairflowintensityincreases,andthedegreeofpenetrationstrengthincreases,it’seasytopenetrateintothecenterofthefurnacerelative
8、ly,sothatthemixtureoffluegasandcoalincreases,theincreasingefficiencyofcoalcombustionisalsoinfavor.Undercertainconditions,astheveloc