管 道 保 温 层 厚 度 的 计 算 方 法（method for calculating thickness of pipeline insulation layer）

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1、管道保温层厚度的计算方法（Methodforcalculatingthicknessofpipelineinsulationlayer）Calculationmethodofthicknessofpipelineinsulationlayer(threemethods)(1)bycontrollingtheoutersurfacetemperatureoftheinsulatinglayer;Thetemperatureofthemediuminthepipelineist=95Theoutersurfacetemperatureofthemainins

2、ulationlayeristw1=34.66tw1=33.4+0.028*(T-50)(ordirectinputaccordingtoprocessrequirements)Theaveragetemperatureofinsulationlayeristp=64.83tp=(t+tw1)/2ThethermalconductivityoftheinsulatingmaterialatTPtemperatureisW/mDEGC1=0.048Theouterdiameterofpipeismdw=0.219Theairtemperaturearoun

3、dthepipeistk=28Windspeedoutsidetheductm/somega=4TheheatreleasecoefficientofthesurfaceoftheinsulatinglayertothesurroundingairisW/(M2=k),alphah=25.53,alphah=11.63+6.95**0.5Apipemaininsulationlayerouterdiameterisd1:d1/dw*ln(d1/dw)=0.1556d1/dw*ln(d1/dw)=2*1*(t-tw1)/lambdaalphah*DW*(t

4、w1-tk)]Maked1/dwxln(d1/dw)=x.LNXlookuptable:X.Lnx=0.1556input,seeTable1laterThex=1.147inputisshowninTable1laterThethicknessoftheinsulatinglayerism=0.0161=/2==d1-dw(x-1)*dw/2(two)calculationbycontrollingthemaximumheatlossThetemperatureofthemediuminthepipelineist=95Theaveragetemper

5、atureofinsulationlayeristp=70.Whentheinsulationthicknessiscalculatedbythismethod,theoutsidesurfacetemperatureisunknownandtheaveragetemperatureischeckedinTable2ThethermalconductivityoftheinsulationmaterialisW/mDEGC,lambda1=0.048inputPipeouterdiametermdw=0.219inputTheairtemperature

6、aroundthepipeistk=28TheheatreleasecoefficientoftheinsulatinglayertothesurroundingairisW/(M2=k),alphah=0.034ThemaximumheatdissipationoftheunitsurfaceisQq=93.Checktable4Themaininsulationlayerofthepipelineisd1:,d1=,0.3527ln(d1/dw),=2*3.14*x,1*(t-tk)/q-alphah]Thethicknessoftheinsulat

7、inglayerism=0.0668Note:whenthemaximumallowableheatlossofthesurfaceofthepipeorequipmentispredetermined,theeconomicthicknessoftheinsulationlayeris:Delta1=0.0037,Delta1=2.69*dw1.2*x11.35*tw11.73/q1.5(three)calculatethethicknessoftheinsulatinglayerwhencontrollingthetemperaturedropThe

8、mediumflowinthepipeiskg/hG=35inputMedium