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1、西安建筑科技大學(xué)碩士論文噴動(dòng)床中氣固兩相流數(shù)值模擬專業(yè):材料學(xué)研究生:范金禾指導(dǎo)老師:徐德龍?jiān)菏啃?guó)先教授摘要本論文重點(diǎn)對(duì)大顆粒流態(tài)化水泥熟料煅燒裝置噴動(dòng)床中物料動(dòng)力學(xué)特性進(jìn)行數(shù)值模擬,旨在通過深入了解噴動(dòng)床中大顆粒流態(tài)化現(xiàn)象,為具有自主知識(shí)產(chǎn)權(quán)的新型流態(tài)化水泥熟料煅燒裝置的工業(yè)化提供理論指導(dǎo)。針對(duì)氣固兩相的流動(dòng)特點(diǎn),用離散顆粒法模擬顆粒相,用連續(xù)介質(zhì)法模擬氣相,氣固相間耦合采用牛頓第三運(yùn)動(dòng)定律,建立氣、固兩相運(yùn)動(dòng)的物理和數(shù)學(xué)模型,自主開發(fā)出三維噴動(dòng)床、流化床內(nèi)氣固兩相流動(dòng)的數(shù)值模擬程序,可用于預(yù)測(cè)床層內(nèi)氣體、顆粒的運(yùn)動(dòng)規(guī)律、壓降及不同操作條件下的流化狀態(tài)。數(shù)值模擬O.11xO.
2、012xO.9m三維大顆粒噴動(dòng)床內(nèi)氣固兩相運(yùn)動(dòng)規(guī)律,模擬結(jié)果顯示:在入口氣流速度22m/s時(shí),噴動(dòng)床內(nèi)存在明顯的噴射區(qū)(顆粒流動(dòng)通道)及顆粒滯止區(qū);噴射區(qū)位于床層中部,其寬度沿床高方向不斷增大,最大寬度為噴動(dòng)床寬度的1/5~1/4;顆粒滯止區(qū)在壁面附近,滯止區(qū)的高度和寬度分別為床寬的3/4和l/4;床內(nèi)顆粒流型呈現(xiàn)不對(duì)稱性,中心區(qū)的顆粒自下而上運(yùn)動(dòng),近壁區(qū)顆粒自上而下運(yùn)動(dòng),形成床內(nèi)顆粒整體循環(huán)運(yùn)動(dòng);床層壓降隨入口氣流速度的增大而增大,當(dāng)入口氣流速度為30m/s(表觀氣速2.73m/s)時(shí),壓降達(dá)到最大值(4100Pa),入口氣流速度繼續(xù)增大,壓降稍有降低,但基本恒定:床體壓降隨顆
3、粒密度增大而增大。關(guān)鍵詡:數(shù)值模擬氣固兩相流噴動(dòng)床西安建筑科技大學(xué)碩士論文ANumericalSimulationoftheGas_SolidTwo-PhaseFlowinaSpoutedBedSpecialty:MaterialScienceName:FanJinheInstructor:.XuDelongXiaoGuoxianABSI。RACrForthepurposeofprovidingatheoreticalguidancetoanewkindofclinkerfiringdeviceusedformanufactureofecologicalcement,anexpe
4、rimentprojecthasbeencarriedout.Thedeviceplannedisacertaintypeofreactorinwhichcoarsegranulesarespoutedinaftuidizafionstate.msthesispresentsmainresultsandcognitionsachievedintheprogram,concentratingonthenumericalsimulationdynamiccharacteristicsofcoal'segranulesspoutedbed.n地gas—solidflowinaspout
5、edbedismodeledbyacombinedapproachinwhichdiscreteparticlemethodandcomputationalfluiddynamicsareusedtocalculatethemovementsofthesolidsandgases,respectively.necouplingbetweengasphaseandsolidphaseWasachieveddirectlybyapplyingtheprincipleofNewton’Sthirdlawofmotion.Inthisway,amodelofmath-physicswas
6、established.Andthenanumericalsimulationprogramoftwo-phaseflowWasdevelopedapplyingtoathree—dimensional(3D)spoutedbedorfluidizedbed.Theprogramwasusedtopredictthegasesandparticlesmotion,pressuredropandfluidizedstatesatvarioasconditions.msimulationWasusedtopredicttheconditionsina3Dlaboratorydevic
7、eofspoutedbedofdimensions0.11X0.012x0.9m,withanozzlelocatedatthecentreofthebed-base.Fortheconditionofgasvelocityof22rn/s.simulationresultsindicatedthatthetwodistinctregiOIlSexisted,whichareanarrowconical-corespoutandastagnantannulus.nepositio