Example 16.3-2 Mass Diffusivity at High Density

> restart;

> eq:=p*DAB/((pcA*pcB)^(1/3)*(TcA*TcB)^(5/12)*(1/MA+1/MB)^(1/2))=a*(T/sqrt(TcA*TcB))^b; eq. 16.3-1 from the last example

> DAB:=solve(eq,DAB);

> DAB:=unapply(DAB,T,p);

> b:=1.823;

> rat:=p*DAB(313,p)/(p*DAB(293,p));

[Maple Math]

> pDAB3130:=rat*pDAB2930;

> pDAB2930:=0.163*atm*cm^2/s;

[Maple Math]

> p:=136*atm: T:=313*K:

> TcA:= 190.7*K: pcA := 45.8*atm: critical properties of methane

> TcB:= 305.4*K: pcB := 48.2*atm: critical properties of ethane

> xA:= 0.8: xB:=0.2: mass fraction of each compound

> pc := pcA*xA+pcB*xB; pseudocritical property of the mixture

> Tc:= TcA*xA+TcB*xB;

> pr:=p/pc; Tr:=T/Tc; pseudo-reduced pressure and temp

[Maple Math]

[Maple Math]

From Figure 16.3-1 on Page 506 of BSL, we can see that (pDAB)/(pDAB0)=0.73

>

> pDAB := 0.73*pDAB3130;

> DAB := pDAB/p;

[Maple Math]

>