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ID:58094982
大小:1.99 MB
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时间:2020-04-23
《不同温度水体空化水动力脉动特性的试验研究-论文.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、第50卷第8期机械工程学报VO1.50NO.82014年4月JOURNALOFMECHANICALENGINEERINGApr.2014DoI:lO.3901/JME.2014.08.174不同温度水体空化水动力脉动特性的试验研究木时素果,2王国玉胡常莉高德明f1.北京理工大学机械与车辆学院北京100081;2.北京机电工程研究所北京100074)摘要:为研究热力学效应对空化水动力脉动特性的影响,采用试验的办法研究温度为279K、298K和318K时绕水翼的非定常空化流动特性。试验在闭式水洞中进行,采用高速摄影的方法观察不吲温度卜绕水翼的空穴形态,采用测力系统测量水翼受到的
2、升阻力,并对升力信号进行频谱分析,得到水翼升力存非定常化阶段的频率特征。结果表明,相同空化数条件下,随着温度的升高,平均升阻力系数降低,升力系数波动程度降低;温度对升阻力系数的影响随着空化数的升高而降低。在不同的空化发展阶段下,温度对升力系数影响的规律不同,宅化形成和片状窄化阶段,温度对升力系数影响较小;云状空化阶段,温度对升力系数影响较大。之所以出现上述规律是因为存同一空化数下,随着温度的升高,空化区域减小;而空化区域越大,温度对空化流动的影响则越大。关键词:热力学效应;温度;空化;动力特性;频率中图分类号:TV131ExperimentalStudyonHydrodyn
3、amicCharacteristicsofCavitatingFlowsaroundHydrofoilunderDifferentWaterTemperaturesSHISuguo·WANGGuoyuHUChangliGAODeming(1.SchoolofMechanicalandVehicular,BeijingInstituteofTechnology,Beijing100081;2.BeijingElectro-MechanicalEngineeringInstitute,Beijing100074)Abstract:Inordertostudythelnfluen
4、ceofthetherlTlaleffectonhydrodynamiccharacteristicsofcavitatingflows,theunsteadycavitatingflowsaroundaClark—Yhydrofoilunder279K,298Kand318Kconditionsarerespectivelyinvestigatedexperimentally.Experimentsarecarriedoutinarectangulartestsectionofacavitationtunne1.Ahigh—speedvideocameraisusedto
5、visualizetheunsteadycavitatingflowpattems,andtheliftanddragcoeficientsaremeasuredbydynamicsforcemeasurementsystem.Thespectralanalysisofthemeasureddataisconductedandthespectrumcharacteristicoftheliftforcearoundthehydrofoilisobtained.Theresultsshowthatwhenthewatertemperatureisincreased,theav
6、eragevaluesofliftanddragcoeficientsdecreaseaswellastheliftfluctuationtendstobemildbykeepingthecaviationnumberconsistent.Theinfluenceontheliftanddragcoeficientsbytemperaturesbecomesweakenwithincreasesofthecavitationnumber.Thefluctuatingscaleoftheliftcoeficientiscorrelatedtotheunsteadycavity
7、closely.Thetemperaturehaslittleefectonthefrequencyofliftwhenitiscavitationinceptionorsheet.Butwhencloudcavityappears,thetemperaturegreatlyaffectsonthefrequencybasedonlift.Tointerprettheconclusionsabove,itisinferredthatwhencavitationnumberisconstant,thecavitati
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