机床有限元热分析中对流换热系数的计算方法研究_阳红

434Vol．43No．420117JOURNALOFSICHUANUNIVERSITYENGINEERINGSCIENCEEDITIONJuly20111009-3087201104-0241-08111*2221．6100652．643000。Y。。。TG502．15AResearchonCalculationMethodsofConvectiveHeatTransferCoefficientsforMachineTools’ThermalAnalysisYANGHong1YINGuo-fu1FANGHui1*LIULi-xin2ZHANGDing-jin2XUDe-wei21．SchoolofManufacturingSci．andEng．SichuanUniv．Chengdu610065China2．ChangzhengMachineToolGroupCo．LtdZigong643000ChinaAbstractThecalculationofconvectiveheattransfercoefficientsisthekeyproblemofmachinetools’thermalanalysis．TakingtheYdi-rectionalscrew-nutfeedsystemofaGantryMachiningCenterasanexampleamethodforthecalculationofconvectiveheattransferco-efficientswasproposedbasedonaneuralnetworkandexperimentaldata．Afiniteelementmodelofthescrew-nutfeedsystemwasbuildasthismethod’sbaseandbyusingthismodel’sthermalanalyticaldataaneuralnetworkwasbuildtosimulaterelationshipsbetweenconvectiveheattransfercoefficientsandthetemperaturefield．Importingmeasuredtemperaturesintotheestablishedneuralnetworkthevalueofconvectiveheattransfercoefficientswascomputed．Finallybycomparingresultsoftheabovemethodandamethodbasedonsimilaritytheorywithexperimentaldatatheaccuracyandvalidityofthismethodwereproved．Keywordsconvectiveheattransfercoefficientthermalanalysisneuralnetworkgantrymachiningcenter1。22－3。。2010－07－102009ZX04002－0131985－..*。2。“”、、、。1K1m2。DOI:10.15961/j.jsuese.2011.04.021。4。。5。。62．0120W/m2·K。。7。8。。。。GM2000A。11．1、、、。GM2000A。1。Y、。1．2．3．4．5．1GM2000AFig．1StructureofGM2000A1．2YY、、、、2。、。1．2．3．4．5．6．2YFig．2StructureoftheYdirectionalscrew-nutfeedsystem1．3YGM2000AY。Y。1Y8m/min240minXZ。23Y。T1～T8T1～T3T4～T7T8。E1、24243T1．T2．T3．T4．T5．T6．T7．T8．E1．E2．3Fig．3DistributionofmeasuringpointsE2。4T1E1。4Fig．4Temperatureandthermaldisplacementmeas-urementattheleftsideofthescrewY。Y8m/min240min5min10s。22．1Y1。2．223、、。ANSYS。SOLID87。－SOLID92。CONTA174TARAE170。9。Y5150164。1Tab．1Materialparametersofmaincomponents/GPa/10－5m·℃－1/W·m－1·K－1/kg·m－3/J·kg－1·℃－1、2071．120．3036．57820460、1351．000．2546．872804802101．300．2850．077004605Fig．5Finiteelementmesh33．1Y5、、、。13424q=Q/V1QWVm3。Q、10。Y2。2Tab．2Resultsofheatproductionratesq/W·m－31689632416633273344273345333703．236。3Tab．3Heattransfercoefficientsofcontactsurfaces/W·m－2·℃－1320018003．3。Y。1ac=fvflλμcpρxyzφ…2acvflλμcpρx、y、zφ。。ac=1．5Δtl14ac=1．63Δt13。Δt。ac=Nu·λl=0．664Re12Pr12λlac=Nu·λl=0．037Re45Pr13λl。NuRePr。。ReGr·PrGr6。2586。a0c=a0c1a0c2…a0c84。6Fig．6Convectiveheattransfercoefficientsofthemodel4Tab．4Initialvaluesofconvectiveheattransfercoefficients/W·m－2·K－1a0c19．72a0c210．51a0c356．64a0c430．11a0c514．23a0c644．71a0c712．36a0c811．25Y。。。4Y、、44243T=T1T2…T7ac=ac1ac2…ac8。、、、11。。4．1T=T1T2…T7ac=ac1ac2…ac8－。RBFBP－12。YTacRBF。RBF7。7RBFFig．7TopologyoftheRBFneuralnetwork7、、。Tq=Tq1Tq2…Tq7qw1=w111w112…w17mmf=f1f2…fmw2=w211w212…w2m8a^qc=a^c1qa^c2q…a^c8q。4．24．2．1RBFRBF14a0c=a0c1a0c2…a0c8。63～10。a0cRBFac5。22、355。3T0=T01T02…T076。7T0=T01T02…T075。7RBFT。3SPREADMatlabRBF。SPREAD1．013。RBFNN=newrbeTacSPREAD3newrbeRBF。NTacNN。5RBFTab．5TargetmatrixofRBFneuralnetworkW/m2·Ka0c1a0c2a0c3a0c4a0c5a0c6a0c7a0c8119．7210．5156．6430．1114．2344．7112．3611．252219．4421．02113．2860．2228．4689．4224．7222．503438．8842．04226．56120．4456．92178．8449．4445．004658．3263．06339．84180．6685．38268．2674．1667．505877．7684．08453．12240．88113．84357．6898．8890．0061097．20105．10566．40301．10142．30447．10123．60112．5054246Tab．6LocationsofmeasuringpointsinthefiniteelementmodelmmxyzT0161729．8641．91－112．87T02499750．81－1707．23－155．26T03275028．36－2990．07－115．79T04928038．84－319．68－79．62T05923533．98－1197．27－73．15T064623－45．37－1423．74－146．41T07909120．22－2733．04－94．477RBFTab．7InputmatrixofRBFneuralnetwork℃T01T02T03T04T05T06T07118．3551．3717．9519．0754．1664．9918．79217．3931．8217．3017．7137．0943．0217．65317．1522．9117．0817．2525．1528．3317．23417．0820．2917．0617．2023．3326．4017．19517．0519．1417．0417．1422．3224．2017．15617．0318．3017．0217．1121．3122．7717．124．2．2Step1240minT'=T1'T2'…T7'Na^mc=simNT'4sima^mc=a^c1ma^c2m…a^c8m。Step2a^mc=a^c1ma^c2m…a^c8ma0c=a0c1a0c2…a0c85。6Tm=Tm1Tm2…Tm7。Step3em=em1em2…em7emj=|Tmj－Tj'|j=12…7。maxem=maxemjmaxem＜0．1Step5maxem0．1Step4。Step4a^mcacac=aca^m[]cTmTT=TT[]m。3acTRBFN。Step1～Step3。Step5a^mc=a^c1ma^c2m…a^c8m。Y8。5a^12ca^12ca0c5、8Tab．8Calculationprocessofconvectiveheattransfercoefficientsa^c1/W·m－2·K－1a^c2/W·m－2·K－1a^c3/W·m－2·K－1a^c4/W·m－2·K－1a^c5/W·m－2·K－1a^c6/W·m－2·K－1a^c7/W·m－2·K－1a^c8/W·m－2·K－1maxe/℃15．866．31271．2724．8112．03237．7611．367．575．5521．992．1492．088．424．0880．703．852．5743．2739．4010．11434．4239．7419．27380．7618．2012．132．5942．983．21138．1212．636．12121．065．783．8524．6656．907．42318．9629．1814．15279．5613．368．912．5963．984．28184．1616．848．17161．417．715．1415．0777．117．65328．7730．0714．58288．1613．779．182．4288．949．54366．1534．4417．24321．0516．3411．240．72397．217．9164．4232．8215．62319．3514．709．600．867108．408．97365．5033．7116．58320．4415．7310．430．81117．828．37364．9133．2416．75319．8015．3910．620．18127．928．51365．1733．4216．27320．4215．3110．210．0864243－。5．1Y。12233a^12ca0c4240min16．6℃。5。9。9Tab．9Resultsofsteady-statethermalanalysisT01/℃T02/℃T03/℃T04/℃T05/℃T06/℃T07/℃maxe/℃18．233．717．918．727．229．219．10a^12018．2133