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1、第50卷第10期機(jī)械工程學(xué)報VOI.50NO.1020l4年5月JOURNAL0FMECHANICALENGINEERINGMaV2014Dol:l0.3901/JME.2014.1O.163離心泵葉輪區(qū)瞬態(tài)流動及壓力脈動特性水王玉川譚磊曹樹良祝寶山(清華大學(xué)水沙科學(xué)與水利水電工程國家重點(diǎn)實(shí)驗(yàn)室北京100084)摘要:目前離心泵過流部件的瞬態(tài)流動分析主要集中在蝸殼內(nèi),對旋轉(zhuǎn)葉輪區(qū)內(nèi)的流動特性研究較少?;赗NGk-e湍流模型和滑移網(wǎng)格,對不同工況下離心泵內(nèi)部瞬態(tài)流場進(jìn)行數(shù)值模擬,計(jì)算得到的離心泵揚(yáng)程和效率曲線與試驗(yàn)結(jié)果吻合較好。在離心泵葉片正背面分別設(shè)置3個監(jiān)
2、測點(diǎn),分析葉輪區(qū)壓力脈動特性。結(jié)果表明,設(shè)計(jì)工況下葉片正背面壓力脈動的主頻為葉輪轉(zhuǎn)頻或2倍葉輪轉(zhuǎn)頻,非設(shè)計(jì)工況下其主頻均為葉輪轉(zhuǎn)頻。從葉輪進(jìn)口到出口,葉片正背面的壓力脈動最大幅值都逐漸增大。同一監(jiān)測點(diǎn)上壓力脈動最大幅值在小流量時最大,約為設(shè)計(jì)工況下5倍。分析小流量工況下葉輪內(nèi)部相對速度分布,葉輪出口處附近隨時間變化的旋渦是內(nèi)部流動不均勻的主要原因,使得離心泵在該工況下運(yùn)行效率低、壓力脈動強(qiáng)度大。關(guān)鍵詞:離心泵;葉輪;瞬態(tài)流動;壓力脈動中圖分類號:TH311CharacteristicsofTransientFlowandPressureFluctuationi
3、nImpellerforCentrifugalPumpWANGYuchuanTANLeiCAOShuliangZHUBaoshan(StateKeyLaboratoryofHydroscienceandEngineering,TsinghuaUniversity,Beijing100084)Abstract:Transientflowanalysesincentrifugalpumparefocusedmainlyonthevolute,whilelittleatentionispaidontherotatingimpeller.Thetransientflo
4、wsfordiferentoperatingconditionsincentrifugalpumparenumericallyinvestigatedusingRNGk-cturbulencemodelandmovingmesh.Thecomputationalresultsofpumpheadandeficiencyshowgoodagreementwiththeexperimentaldata.Threemonitorpointsarepositionedonthebladepressureandsuctionsurfaces.Thepressureflu
5、ctuationsonmonitorpointsareanalyzedanddiscussed.Fordesignflowrate,thedominantfrequenciesonbladesurfaceare1or2timesrotatingfrequency.Thedominantfrequencyequalstherotatingfrequencyforbothsmallandlargeflowrates.Theamplitudesofpressurefluctuationincreasegraduallyfromtheimpellerinlettoou
6、tlet.Themaximumamplitudeofpressurefluctuationforsmallrateisabout5timesthanthatfordesignflowrateatthesamemonitorpoint.Therelativevelocitydistributionsinimpellerareanalyzedforsmallflowrate.Theresultsshowthatthevortexesevolvingwithtimeattheimpelleroutletnearthepressuresurfacegiveriseto
7、theflownon-uniformity,inducinglowoperatingeficiencyandlargepressurefluctuationforcentrifugalpump.Keywords:centrifugalpump:impeller;transientflow:pressurefluctuation當(dāng)導(dǎo)葉數(shù)和葉片數(shù)相等時,流體作用力較小,而導(dǎo)0前言葉數(shù)和葉片數(shù)不同時,壓力脈動幅度較小。張兄文等采用雙重時間步法對離心泵內(nèi)部流動進(jìn)行了數(shù)離心泵是一種應(yīng)用廣泛的通用機(jī)械,過流部件值研究,結(jié)果表明葉輪出口的射流一尾跡結(jié)構(gòu)相對蝸內(nèi)部流動狀況對其
8、運(yùn)行特性具有重要影響j。由于殼不同位置