工程热力学题型分析

()()158520,,,,;,,,,:::(,100084):14:352:200042200041:ISBN7302:0000100000:0.0019899,,,,,,,,,1989,,,,,:1.,;2.,;3.;4.,;5.,;6.,;7.331520,,1,27,3,4,56,,90,1998.12(),,,,,,,,,,,,,,,,,,,,,,,331,,,,,,,,,,,,,,1986.8C,c;(),cp,cV;Cm,Cp,m,CV,m;;E,e;Ek,Ep;Ex,Exm,ex;;ExQ,ExU,ExH;;exq,exu,exh;;F,f;G,Gm,g;;Gf,mH,Hm,h;;Hf,m(-Hu),(-Hu,L),(-Hu,h)();;Kp,Kx,KcMm,qm;,Ppp0pgQ,q,;Qp,QV;qVrR,Rg;S,Sm,s;;SmT,t;U,Um,u();;V,Vm,v;;W,w,;,wWnet,wnet;Ws,ws;Wt,wt;WR,usexxZzV,,,t;sTJ,;a,b,c,,,,conc.vDPEexelf,,g,,,HIRi,inisoL,,max,mixnoutPp,,R,rss,,trv,w,,,0101.325kPa111.111.281.3131.4161.5181.6221.7242262.1262.2352.3562.4652.5873913.1913.2943.3993.41143.51183.61293.71363.81443.91533.1016841734.11734.21754.3Maxwell1774.41844.51924.61944.72084.82134.92214.102254.1122852305.12305.22465.32525.42745.52975.631763236.13236.23446.336773737.13737.23827.33977.44087.54297.643411.11.1.11.,,,,2.,(,)3.;;,(),,,,,T2Tcp0.1pc,T,4.,(pvTshs)(),(1),5.,6.:,,:(1)(2),()(3),(4),(5),,,(6),(7),(8),,7.:;,qTr0,dsqTr,Siso0,(1),2,,,(2),(3),,,,8.W[kJ],w[kJ/kg],P[kW]9.,,10.,,,1.1.21.1qV,0,1=1m3/min,p1=0.1MPa,t1=20;qV,2=0.12084m3/min,p2=0.9MPa,t2=20,qV,0,3,t3p3:,,,,,3:(1),11,(2)11(),11(3),,(4)qm(101.325kPa,0):qV,0=22.410-3Mqm,M,kg/mol:qV,0,3=qV,0,1+qV,0,2qV,1=qV,0,1,qV,2,qV,0,2:qV,0,2=qV,2p2p20T20T2=0.120840.90.1013252732934=1.0m3/min,qV,0,3=qV,0,1+qV,0,2=1+1=2m3/min(5)Q=0,Ws=0,T=0Kh=0,Cp,m22.410-3(qV,0,1T1+qV,0,2T2)=Cp,m22.410-3qV,0,3¡¤T3T3=1293+12932=293K(t3=20)(6),:S=M22.410-3[qV,0,1s1+qV,0,2s2-qV,0,3s3]=0:qV,0,1(s1-s3)=qV,0,2(s3-s2),:cplnT1T3-Rglnp1p3=cplnT3T2-Rglnp3p2,RgT1=T3=T2,lnp1p3=lnp3p2,p3=p1¡¤p2=0.3MPa,p3,max:,(1)p3,max,:qm,1cpT1+qm,2cpT2=qm,3cpT3pqV,0=qmRgT,p1qV,0,1RgT1¡¤T1+p2qV,0,2RgT2¡¤T2=p3qV,0,3RgT3¡¤T35p1qV,0,1+p2qV,0,2=p3qV,0,3p3=0.11+0.912=0.5MPa,pqV,0qmRgT,,T3,p3!(2),:qV,3=qV,1+qV,2=1+0.12084=1.12084qV,1qV,2,,:,1.212?T0=300K,cp,?126:(1),,,,(2),,:S=1147.68(s4-s1)+1256(s2-s3),(s2-s3)=h2-h3T2,(s4-s1)=(s4-s2)+(s2-s1)12,43,s4=s3,(s2-s1),21cpTdTcp,h2-h1t2-t1,:S=1147.68(s3-s2)+1147.68h2-h1t2-t1lnT2T1+1256(s2-s3)=1147.68h2-h1t2-t1lnT2T1-108.32h3-h2T2=1147.68858.3-675.7201.36-160ln201.36+273160+273-108.322793-858.3201.36+273=462.247-441.788=20.459kJ/(h¡¤K),,:=T0¡¤S=30020.459=6.138103kJ/h:(1),,,;,,,(2),(s4-s1)7,(s4-s1)1.21.2.1,(),,,,1.2.21.3,13(a),,13(b),??138:(1),,13(a),13(b)WQ(2),,14(a),14(b)W,14(3),14(a)(b)W(,),W=W+W,Q(,),Q,Q=Q+Q(4),,;(1314,)9:(1)(2),,,1.4,,,?:(1),,,Q=0,15(a),,W:0=U+W,U=-W0,15,,(2),15(b)WQ0,1.5,?:16,01,,,,Q,,W,W,,U=Q-WQW,©¦Q©¦©¦W©¦,U0,16,16(b),WQ,171.6,,A,,17B(1),(2),(3)(4),(,)1.7p,v,u1kg111kg,:1kg,,,,pv,,,-pv,,,q=0,uu,:u-u=q-w=pvu=u+pv=h:(1),h,u,(2)1kg,,1.818,,,,(1);(2);(3),:(1),Q;(2),W;(3),,:,,,,,21181.31.3.1,31z:21dz=z2-z1dz=0:dz=zxydx+zyxdyzxy=M,zyx=N,,Myx=Nxyz1.3.21.9???,,,,,,,,1.10z,yx?(1)dz=2xydx+x2dy;(2)dy=(x+z)dx+(x-z)dz;(3)dx=y2ezdz+yezdy:(1)dz=2xydx+x2dy,M=2xy,N=x2,:Myx=2x,Nxy=2x,,z41(2)dy=(x+z)dx+(x-z)dz,M=x+z,N=x-z,Mzx=1,Nxz=1,y(3)dx=y2ezdz+yezdy,M=y2ez,N=yez,Myz=2yez,Nzy=yez,,x1.11s=f(T,p),h?:s=f(T,p),ds=sTpdT+spTdp,dh=Tds+vdp,:dh=TsTpdT+TspT+vdpTsTp=M,TspT+v=N,MpT=T2sTp+sTp¡¤TpT=T2sTpNTp=spT+T2sTp+vTpMaxwell(4),-spT=vTp,NTp=T2sTpMpT=NTp,dh,h1.12su,uvT=TpTv-p51:,u,du=uTvdT+uvTdvTds=du+pdv,ds=1T¡¤uTvdT+1TuvT+pdv1TuTv=M,1TuvT+p=N,MvT=1T2uTv,NTv=1T2uTv-1T2uvT+1TpTv-pT2s,MvT=NTv,:1T2uTv=1T2uTv-1T2uvT+1TpTv-pT2uvT=TpTv-p1.41.4.1(,,),1.4.21.13(TH),61(TL),,19,19,?:,,,,,,,:,,,,1.14,,??:110,110,,,,,,:,;,,71,;(,)1.15?:,,,,,1.51.5.1,,,,K(),1/273.16,273.16K(273.16K),81T(p)=273.16pptrT(V)=273.16VVtrptrVtr:TV=limptr0T(p)=273.16limptr0pptrTp=limp0T(V)=273.16limp0VVtrTVTp,TV=Tp=T,,:t/=T/K-273.15:t/=59(t/-32)1.5.21.16,,?,?:,t/=t/(a)t/=32+1.8t/(b)(a)(b):t/=32+1.8t/0.8t/=-32,91t/=-40=t/=-40,1.17,100,TiTb,:(1)Ti=100limptr0(pb/pi)-1;(2)limptr0(pb/pi)=rs,rsdrsTidTiTi=3.73drsrs;(3)TdTT=drr+3.73drsrs,r=limptr0ppiptr,p,pb,piTtrTTbTi:(1),:Ti=273.16limptr0piptr,Tb=273.16limptr0pbptr,Tb-TiTi=limptr0pbpi-1,Ti=100limptr0(pb/pi)-1=100rs-1(a)(2)(a)rs,:dTi=100(rs-1)2drs(),rsdrs,Ti:dTiTi=drs(rs-1)=rsrs-1¡¤drsrs02rs=limptr0pbpi=1+100Ti373273,:dTiTi3.73drsrs(3)TT=Tilimptr0ppi=TirdT=rdTi+TidrdTT=dTiTi+drr=drr+3.73drsrs,,3.73drsrs,1.18,,:TdTT=drr,r=limptr0pptr:,:T=273.16limptr0pptr=273.16rdT=273.16drdTT=drr,1.19,ptr=500mmHg(1mmHg=133.3224Pa);,p=734mmHg,12?,,ptr200mmHg,p=293.4mmHg,,ptr=100mmHgp=146.68mmHg,:(1),:Tb=273.16¡¤734500=401.00K(2):Tb=273.16¡¤293.4200=400.73K,:Tb=273.16¡¤146.68100=400.67Kptr,Tb111,,400.59K1111.61.6.1,22,,,(,)1.6.21.20,(1)(2)(3)50100(4)(5)10025(6)(7),,:(1),,,,(2),,,,(3),,321.211.71.1,(1)(2)(3),(4),,(5)(6)(7),,1.2ds=cpTdT-vTpdp,cppT=-T2vT2p1.3p1=0.5MPa,V1=0.4m3,V2=0.8m3,1.4,pV1.3=600kPa,0.3m3,0.5m3,1.50.3m,150kPa42,0.4m,1.61kg112,AB,BC,CA,ACBA?112522,,,,2.12.1.11.:W=V2V1pdV(21):(1),,,(2)(3),,(),pVpV622.,,(),W=FdX(22),F,X,FdX(22)W=pdV-dL-dA-E¡¤d(V¡¤P)-0Hd(VM)(23),-dL,dL(,dL);-dA,A;-Ed(VP),E,P(),V;-0Hd(VM)H,M(),03.W=MdM,W=M,P=W=Md=M=M¡¤2/60(24),4.pv,pv,72,,,,pv5.wtwt=ws+12c2+gz=w+p1v1-p2v2(25),wswt=-21vdp(26)2.1.2W=FdX212.121,1kg,1(p1,v1)2(p2,v2),132,12,,:(1)132pv,,(21)w132=31pdv+23pdv=p1(v3-v1)+0=p1(v2-