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clear;
clc;
printf("\t Example 2.21\n");
//stefan tube experiment(pseudo steady state diffusion)
Ml=92; //molecular weight of toluene
T=(303); //temperature in kelvin
pt=1*1.013*10^5; //total pressure in pascal
R=8314; //universal gas constant
t=275*3600; //after 275 hours the level dropped to 80mm from the top
zo=20*10^-3; //intially liquid toluene is at 20mm from top
zt=77.5*10^-3; //finally liquid toluene is at 80mm from top
//air is assumed to be satgnant
d=820; //density in kg/m^3
pa=(57/760)*1.0135*10^5; //vapour pressure of toluene in at 39.4degree celcius
cal=d/Ml; //conc. at length at disxtance l
ca=pt/(R*T); //total conc.
xa1=pa/pt; //mole fraction of toluene at pt1 i.e before evaporation
xb1=1-xa1; //mole fraction of air before evaporation i.e at pt1
xb2=1; //mole fraction of air after evaporation i.e at pt.2
xa2=0; //mole fraction of toluene at point 2
xbm=(xb2-xb1)/(log(xb2/xb1));
//t/(zt-zt0) = (xbm*cal*(zt+zo))/(2*c*(xa1-xa2)*t);
Dab=(xbm*cal*(zt^2-zo^2))/(2*ca*t*(xa1-xa2));
printf("\n the diffusivity of the mixture in stefan tube of toluene in air is :%f*10^-5 m^2/s",Dab/10^-5);
//end
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