Example 13.2-1 on pages 405-407

>  restart;
>  T0:=70*F; Dia:=2*inch; w:=70*lbm/hr; Tw:=250*F; Tout:=230*F;
>  mu150:=.049*lbm/(ft*hr); mu250:=.055*lbm/(ft*hr);
>  Cp:=0.241*Btu/(lbm*F); k:=0.0169*Btu/(hr*ft*F); Pr:=0.698;
>  Cp*mu150/k; Just checking Pr.
[Maple Math]
>  inch:=ft/12;Reb:=Dia*V*rho/mu150;
>  P:=1*atm;MW:=28.97*lbm/lbmol;Rgas:=82.05*cm^3*atm/(mol*K);rho:=P*MW/(Rgas*(150+459)*R);
>  K:=1.8*R; mol := 0.2204620E-02*lbmol; cm := 0.3280840E-01*ft;
>  rho;
[Maple Math]
>  eq:=Pi*(Dia/2)^2*V*rho=w;
>  V:=solve(eq,V);
[Maple Math]
>  Reb; Checks with 13.2-24
[Maple Math]
>  eq:=hln*Dia/(Reb*Pr^(1/3)*k*(mu150/mu250)^0.14)=0.0039;
>  hln:=solve(eq,hln);
[Maple Math]
>  eq:=w*Cp*(Tout-T0)=hln*Pi*Dia*L*(dT1-dT2)/log(dT1/dT2);
[Maple Math]
>  dT1:=Tw-T0; dT2:=Tw-Tout;
[Maple Math]
[Maple Math]
>  eq;
>  solve(eq,L); Close to the values found in the text.
[Maple Math]
>