露天管道层绝热保温加电伴热防冻方案及其经济分析_李炎锋

北京工业大学李炎锋贾衡李俊梅认为在寒冷地区露天管道特别是小管径管道单纯靠增加保温层厚度不能防止管道冻结,提出绝热保温加电伴热防冻方案,并分析其热力学特性和经济性,给出计算最佳保温层厚度的公式管道防冻经济分析保温层FreezingpreventionforoutdoorpipeswithinsulationlayerandheatingwireanditseconomicanalysisByLiYanfeng,JiaHengandLiJunmeiAbstractConsidersthatthefreezingcannotbepreventedforoutdoorpipes,especiallysmalldiameterpipesincoldareasifonlydependonincreasingthethicknessofinsulatingmaterial.Presentsthefreezingpreventionmethodofincreasingthethicknessofinsulatingmaterialtogetherwithheatingwire.Analysesitseconomicandthermodynamiccharacteristics.Givesoutaformulatocalculatetheoptimalthicknessofinsulatingmaterial.Keywordstube,freezingprevention,economicanalysis,insulationlayerBeijingPolytechnicUniversity,China,,,1[1],10,,,,():Q=2l(Ti-T2)lnD1Di1+lnD2D12(1)Di,D1,D2;Ti;T2,,,T2;l;1,2,,,,:Tn=Tn-1-Qn-1mcp(2)Qn-1=dtTn-1-T2lnD1Di1+lnD2D12(3)nn;dt,cp,m0,1112暖通空调HV&AC2002年第32卷第6期,,19719,,,100022(010)67391147Email:[e-mail]:2001-04-16100:T0=12,T2=-25,1,2520.033W/(m2),(DN20),200mm,,,,,:,,,(),,22[2],,2[3],2.1:Ai=A1(D22-D21)4+A2(4)A1,/m3;A2,/m,A2=t1-t2012lnD2D1PL=t112lnD2D1PL(5)t1;t20,,,;L,W/m;P,/m,:=D2-D12(6)2.2,,,,,Ar,,Ar=Bt210-612lnD2D1+1D22=Bt210-6Rt(7)B,/kWh,1203000h,2,[4]2=11.73+U,URt,t=t1-t21,t212.3,n,,S:N=ie(1+ie)n(1+ie)n-1(8)ie=i1+1i2+1-1;i1;i2,:,ie=i1,i1=0.05:A=NA1(D22-D21)4+A2+Ar(9)A=0:D22lnD2D1+2=10-3Bt2ND2A1LD2lnD2D12-4Pt11-2D22lnD2D1(10)(10)D2,()((7)),A2,,(10),,,,,;113暖通空调HV&AC2002年第32卷第6期(10)1-2D221,,,(10):D22lnD2D1+2=10-3Bt2ND2A1LD2lnD2D12-4Pt1lnD2D1(11)(11)1D2,Rt,(7):q=10-3DNBt2LA1LlnD2D12-4Pt1D2lnD2D1(12):Amin=10-3DNBt2LA1LlnD2D12-4Pt1D2lnD2D1+AiN(13),A1LlnD2D12-4Pt1,A1PL4t1lnD2D12,,AiPL,3DN25(),-10,4.8m/s:DN25,t10=25;5,-10,B393/kWh();i15%;10a;:,=0.033W/(m2);:1000/m3;DTIP-832.85/mD2,opt=0.070m,D1=0.026m,opt=0.022m,,=30mm1,(10mm),3,,,1/W/m(+)//m/mmDN207.3451.1730DN809.6662.8040DN10011.7065.5640DN20016.5485.73503,4,-10:,4,4,:4.1,,4.2,,,,;,4.3,,,,A1PL1,..:,19882,..,2001,27(1):100-1033,,,..:,19974..:,1998114暖通空调HV&AC2002年第32卷第6期