blob: 7a3c7fe8f36bc178af8173196d992109822274a7 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
clear;
clc;
printf("\t Example 2.17\n");
ya2=0; //molefraction at pos.2
ya1=0.1; //molefraction at pos.1
T=(273); //temperature in kelvin
pt=1*1.013*10^5; //total pressure in pascal
z=2*10^-3; //gas film thickness in m
Dab=.198*10^-4; //diffusion coefficient in m^2/s
R=8314; //universal gas constant
//ammonia is diffusing through an inert film 2mm thick
//for gase Dab=T^3/2
//Dab1/Dab2=(T1/T2)^3/2
T2=293; //final temperature in kelvin
T1=273; //initial temperature in kelvin
Dab1=0.198*10^-4; //initial diffusion coefficient
Dab2=((T2/T1)^(3/2))*Dab1; //final diffusion coefficient
Na=Dab2*pt*log((1-ya2)/(1-ya1))/(z*R*T2); //diffusion flux in kmol/m^2*s
printf("\n flux of diffusion of ammonia through inert film :%f *10^-5 kmol/m^2*s ",Na/10^-5);
//if pressure is also incresed from 1 to 5 atm
//for gases Dab=(T^3/2)/pt;
//Dab1/Dab2=(T1/T2)^3/2*(p2/p1)
T2=293; //final temperature in kelvin
T1=273; //initial temperature in kelvin
pa2=5; //final pressure in atm
pa1=1; //initial pressure in atm
p=pa2*1.013*10^5;
Dab1=.198*10^-4; //initial diffusion coefficient
Dab2=((T2/T1)^(3/2))*Dab1*(pa1/pa2); //final diffusion coefficient
Na=Dab2*p*log((1-ya2)/(1-ya1))/(z*R*T2); //diffusion flux in kmol/m^2*s
printf("\n flux of diffusion of ammonia if temp. is 20 and pressure is 5 atm :%f*10^-5 kmol/m^2*s ",Na/10^-5);
printf("\n \n so there is no change in flux when pressure is changed");
//end
|
