学科分类
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4 个结果
  • 简介:Theparametricapproachtodesignofhullformwasstudiedinthiswork,whichprovidesthemeansforquickgenerationandvariationofhullformforthehydrodynamicoptimizationofhullform.

  • 标签: 水动力学 参数 水力学 研究
  • 简介:Basedonestablishednumericalmethodsandhydrodynamicperformancetestingfacilities,CFDtechniqueareappliedtoimprovethedesignoftheimplantableaxialflowbloodpumpandtheflowanalysis.(1)Applyingbrushlessmachinemagnetsteel,reducingitsthicknesswhileincreasingthelength,theflowchannel'scross-sectionisincreased,withnospaceconnectionbetweenthelargeandthesmallrotators,andwithaconetransitionsegmentfromthebearingtotheprincipalaxis,theflowismadesmoother.Therotatingspeedisloweredby1000rpm-1200rpmunderthesameflowrateandpressurehead,andthusthehemolysiscanbeavoided.(2)Differentoutletstatorguidingvanesareselectedforthesamebloodpumpforanalysesofhydrodynamicperformancesandflowfields.Anexcellentdesignnotonlycanregulatetherotatingflowfieldintoanaxialone,reducethecirculationlossandimprovethepumpefficiency,butalsocanavoidbackflow,vortexandsecondaryflowatthepumpoutlet,andthusthethrombuscanbeprevented.(3)Thecalflivetestsshowthatsomeresidualclotsexistattheinnerwalloftheoutletconnectionbends,whichareanalyzedandexplainedbyCFDtechniquesandthecorrespondingimprovementsareproposed.AllresultsareverifiedbyhydrodynamicperformancetestsandPIVflowfieldtests,andconsistentconclusionsareobtained.

  • 标签: 轴流式血泵 流程泵 植入式 技术分析 应用 设计
  • 简介:Inphysicalmodeltestsforhighlyreflectivestructures,oneoftenencountersaproblemofmultiplereflectionsbetweenthereflectivestructuresandthewavemaker.Absorbingwavemakerscancancelthere-reflectivewavesbyadjustingthepaddlemotion.Inthispaper,weproposeamethodtodesignthecontrollerofthe2-Dabsorbingwavemakersysteminthewaveflume.Basedonthefirst-orderwavemakertheory,afrequencydomainabsorptiontransferfunctionisderived.Itstimerealizationcanbeobtainedbydesigninganinfiniteimpulseresponse(IIR)digitalfilter,whichisexpectedtoapproximatetheabsorptiontransferfunctionintheleastsquaressense.AcommonlyusedapproachtodeterminetheparametersoftheIIRfilterisapplyingtheTaylorexpansiontolinearizethefilterformulationandsolvingthelinearleast-squaresproblem.However,theresultisnotoptimalbecausethelinearizationchangestheoriginalobjectivefunction.Toimprovetheapproximationperformance,weproposeaniterativereweightedleast-squares(IRLS)algorithmanddemonstratethatwiththefiltersdesignedbythisalgorithm,theapproximationerrorscanbereduced.Physicalexperimentsarecarriedoutwiththedesignedcontroller.Theresultsshowthatthesystemperformswellforbothregularandirregularwaves.

  • 标签: 最小二乘算法 加权最小二乘 设计方法 主动吸收 造波机 控制器