微谐振式低速气体流速传感器的有限元模拟(英文).docx

1、第4卷第3期2006年9月纳米技术与精密工程NanotechnologyandPrecisionEngineeringVol.4No.3Sep.2006FEASimulationofResonantLow-VelocityGasFlowMicrosensorCHENJianReceiveddate：2006-05-22.CHENJianReceiveddate：2006-05-22.Towhomcorrespondenceshouldbeaddressed.E-mail:chenjianO4,CHENDe-yong,WANGJun-bo(StateKeyLaboratoryofTransduc

2、erTechnology,InstituteofElectronics,ChineseAcademyofSciences,Beijing100080,China)Abstract:Anovelresonantmicroscrisormodeledonwindreceptorofinsectswhichcandetectlowvelocitygasflowisdemonstrated.Tofurtherevaluatethisdesign,FEAsimulationbasedonANSYSisused.TherelationshipbetweenReynoldsnumberanddragcocE

3、ficicntofinfinitelongbeamwhichhelpsdetenninelinearregionofthismicrosensorisobtainednumerically.Fluid-structuralcoupledanalysisisconductedtofindtherelationshipbetweenvelocityofgasflowandfrequencyshiftofthismicrosensor.TheresultofFEAsimulationshowsthatwhenReynoldsnumberisbelow1,thereexistslinearrelati

4、onshipbetweeninputandoutputofthismicrosensorwhosesensitivityis1.6H(cms-1).Keywords:MEMS;resonantgasflowsensor;FEAsimulation；fluid-stncturalcouplingArticleID：1672-6030(2006)03-0245-03微谐振式低速气体流速传感器的有限元模拟陈绽L陈德勇，王军波(中国科学院电子学研究所传感技术国家重点实验室，北京100080)摘要：提出一种基于昆虫风速接受鼻的微谐振式仿生伟感器，用以测量低速气体流动.由于设计的复杂性，使用有限元模拟对其

5、进行评估.基于有限元模拟得到流体雷诺教与其绕流无限长梁的粘滞系数的数值关系，从而有助于确定该传感器的线性工作范围.使用有限元模拟进行流体结构根合分析，得到气体流速与固有频率偏移的数值关系.有限元模拟结果证实当雷诺数小于1时，传感器的输入与输出呈现线,性关系，其灵敏度为1.6Hz/(cms*).关键词：微机械电子系统；谐振式气体流域传感器；有限元模拟；流体-结构耦合Inordertoescapefromdanger,insectshavethea-bilitytodetectlowvelocitygasflowbyusingwindreceptoratthetail11,2,.Biomimeti

6、cmicrosensorsderivedfromthiskindofmechanoreceptorbasedonpiezoresistive3_6-orcapacitivedetectionhavebeenunderfocus.Toenhanceitsresolutionandmakeitmoreimmunetoenvironmentalnoise,anovelmicrosensorbasedonresonantprincipleincludingcantilever-basedthinfilmandDETF(double-endedtuningfork)hasbeenproposed.How

7、ever,thismicrosensorinvolvesinteractionbetweenfluiddomainandstructuraldomainsothatitistoocomplicatedtodrawanalyticalexpression.Tosolvethisproblem,FEAsimulationisconductedtoevaluatethisdesign.Firstly,therelationshipbetweenReynoldsnumberofgasflowanddistributedforceactedonthinfilmisobtainednumericallyw

8、hichhelpsfindlinearregionofthismicrosensor.Fluid-structuralcoupledanalysisisconductedtofindtherelationshipbetweenvelocityofgasflowandfrequencyshiftofthismicrosensor.TheresultofFEAsimulationshowsthatwhenReynoldsnumberisbelow1,thereexistslinearrelationshipbetweeninputandoutputofthismicrosensorwhosesen

9、sitivityis1.6Hz/(cms).1 FEAsimulationtofindrelationshipbetweendragcoefficientandReynoldsnumberThenovelresonantmicrosensorisshowninFig.1whichincludescantilever-basedthinfilmwhichistreatedasinfinitelongbeamtosensegasflowanddouble-endedtuningfork(DETF)astheresonator.Thisdesignisbasedontheassumptionthat

10、whengasflowrangesinlowReynoldsnumber,dragforcewhichisthefunctionofgasvelocitycanbedominantcomparedtootherforcesinmicro-size2.ThemainprincipleisthatwhenthereexistsgasflowinYdirectionpassingaroundcantilever-basedthinfilm,thedragforcewhichisthefunctionofvelocityofgasflowwouldbendcantilever-basedthinfil

11、m.ThedefectionofthinfilmwouldbendDETFandmodifyitsintrinsicfrequency.Inmicrodomain,whenlow-velocitygaspassesa-roundinGnitelongbeam,thereexistsdistributeddragforceFdactingonthisbeamwhichisexpressedas产0必“冲(1)WhereCAp,V,Bstandsfordragcoefficient,densityandvelocityofgasflowandwidthofinfinitelongbeamrespe

12、ctively.ThemainproblemisthatCdisnotaconstantvalueanditisnearlyimpossibletodrawanalyticalexpressionwhengasflowpassesaroundinfinitelongbeaminsteadofcylinder.Inthispaper,FEAsimulationisusedtofindrelationshipbetweenCdandReynoldsnumberR,whereRfisexpressedasWherestandsforviscosityofgasflow.Themainideaisth

13、atbymeansofcoupled-fielda-nalysis,relationshipbetweenstraineatthebottomofinfinitelongbeammadeofsiliconandvelocityofgasflowisobtainedshowninFig.2inwhichstraincanbeexpressed(3)WhereL,H,E,standforthelength,heightofthebeamandYang*smodulusofsilicon.-/fl-0.2-l.00X6i.ooxi(ri.ooxio4l.OOXlbi.ooxio-*dl.ooxibi

14、.ooxio,1.00X10*i.ooxio-10i.ooxio-1.00X10121.00X10IJI00010000100000100000010000000Velocityofmasflow/Fig.2RelationshipbetweenvelocityofgasflowandstrainatthebottomofinfinitelongbeamBasedonEq.(1)(3),therelationshipbetweenRfandCAcanbeobtainedandisshowninFig.3.Changingtheheightofinfinitelongbeam(H)andrepe

15、atingthesimulation,theinfluenceofratioH/BondragcoefficientisobtainedandisshowninFig.3.FromFig.3,wecanseethatwhenH/BnO.2,theeffectofthechangeofthisratioondragcoefficientisrelativesmall.Itisalsoimpliedthattheincreaseofmeshingdensityhasnoeffectontheresultobtainedabove.Fig.3RelationshipbetweenReynoldsnu

16、mberandC,basedoninfinitelongbeamFig.3RelationshipbetweenReynoldsnumberandC,basedoninfinitelongbeamWhenH/Bequatesto0.1,andthegasrangesinlowReynoldsnumber(R,V1),Cdcanbeexpressedas广3.923百(4)WhenA,v1,substituteEq.(4)intoEq.(1),thedistributedforceFabecomesFd=土保切=().gyv(5)Eq.(4)showsthatwhenlmondon,Canada

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