blob: 50fbdbf463d03162278b9370e8c2dbdbea7c6906 (
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
|
clc
clear
p1=10; //pressure in bar
//At 10 bar and 300 deg celsius, from steam tables of superheated steam
hsup=3051.2 //kJ/kg
Tsup=300+273; //temp. of steam in K
//At 10 bar and 300 deg celsius, from steam tables of dry saturated steam
Ts=179.9+273 //temp. of steam in K
vg=0.194; //m^3/kg
//By vg/Ts = vsup/Tsup
vsup=vg*Tsup/Ts;
u1=hsup-p1*10^5*vsup/10^3;
p2=1.4; //new pressure in bar
x2=0.8; //dryness fraction
//At 1.4 bar, from steam tables
hf2=458.4; //kJ/kg
hfg2=2231.9; //kJ/kg
vg2=1.236; //m^3/kg
h2=hf2+x2*hfg2; //enthalpy of wet steam (after expansion)
u2=h2-p2*10^5*x2*vg2/10^3; //internal energy of this steam
Du=u2-u1; //change in internal energy per kg
printf(' (i) The Internal energy of superheated steam at 10 bar is: %4.1f kJ/kg. \n',u1);
printf(' (ii) The Change in internal energy per kg is: %2.1f kJ. \n',Du);
printf(' (Negative sign indicates DECREASE in internal energy.)' );
|
