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1、第40卷第2期蘭州理工大學(xué)學(xué)報(bào)Vol.40No.22014年4月JournalofLanzhouUniversityofTechnologyApr.2014文章編號:1673-5196(2014)02-0018-05基于LBM算法的強(qiáng)迫對流合金枝晶生長相場法模擬王智平1,2,王喜君1,馮力1,朱昶勝1,3,路陽1(1.蘭州理工大學(xué)甘肅省有色金屬新材料重點(diǎn)實(shí)驗(yàn)室,甘肅蘭州730050;2.蘭州理工大學(xué)甘肅省有色金屬及復(fù)合材料工程研究中心,甘肅蘭州730050;3.蘭州理工大學(xué)CAD中心,甘肅蘭州730050)摘要:將二元合金枝晶生長的相場模型與模擬流場的LatticeBoltzmann(LBM
2、)模型相藕合,建立模擬在強(qiáng)迫對流狀態(tài)下枝晶生長的二維相場-LBM模型(PF-LBM),模擬Al-4.5%Cu(質(zhì)量分?jǐn)?shù))二元合金在強(qiáng)迫對流環(huán)境下凝固過程中枝晶生長,實(shí)現(xiàn)過冷熔體流動場與相場耦合.結(jié)果表明:計(jì)算流場的LBM算法對樹枝晶生長模擬效率高,數(shù)值穩(wěn)定性好.在純?nèi)苜|(zhì)擴(kuò)散時(shí),枝晶周圍的溶質(zhì)分布均勻,各方向枝晶尖端生長速度一樣,枝晶的生長形貌呈現(xiàn)對稱.有強(qiáng)迫對流情況時(shí),熔體的流動改變了枝晶周圍的溶質(zhì)分布,上游的溶質(zhì)被沖刷到下游,致使上游成分過冷度大,下游成分過冷度小,枝晶的尖端生長在迎游方向的速度大于純擴(kuò)散時(shí)的速度,而在下游方向枝晶生長受到抑制,形成與純?nèi)苜|(zhì)擴(kuò)散時(shí)不一樣的非對稱的枝晶生長形貌
3、.關(guān)鍵詞:相場;枝晶生長;LatticeBoltzmann方法中圖分類號:TG248;TG244文獻(xiàn)標(biāo)識碼:APhase-fieldsimulationofalloydendriticgrowthbasedonLBMalgorithminforceflow1,2,WANGXi-jun1,FENGLi1,ZHUChang-sheng1,3,LUYang1WANGZhi-ping(1.StateKeyLaboratoryofGansuAdvancedNonferrousMetalMaterials,LanzhouUniv.ofTech.,Lanzhou730050;2.ResearchCente
4、rofGansuNonferrousMetalMaterialsandCompositeMaterialsEngineering,LanzhouUniv.ofTech.,Lanzhou730050;3.CADCenter,LanzhouUniv.ofTech.,Lanzhou730050)Abstract:TheLatticeBoltzmannMethod(LBM)wascoupledwithaphase-fieldmodeltosimulateden-dritegrowthofAl-4.5%Cu(masspercent)binaryalloywithfluidflowduringsolid
5、ification,thereby,phasefield-LBMmodel(PF-LBM)wasestablishedtosimulatethedendriticgrowthofundercooledmeltinaforcedlaminarflowstate.TheresultsshowthatthemodelhavehighcomputationalefficiencyandgoodnumericalstabilityinsimulatingdendriticgrowthbycombiningtheLBM.Thedendriteshapesaresym-metricalwhenthepur
6、esolutediffused,thedendritesevenlydistributearoundthesolute,andthedendritetipgrowthrateisthesame.However,themeltflowchangesolutedistributionaroundthedendritewhenthesituationiswithforcedconvection,thesoluteiswashedfromupstreamtodownstream,resultinganlargecomponentsundercoolingintheupstreamandansmall
7、undercoolinginthedownstream,asaresult,thegrowthvelocityofupstreamdendritictipishigherthanthatwhenthepuresolutediffuse,butthedownstreamdendritictipisinhibitedandthedendriteshapesareunsymmetricalassameasthatw