Challenge

Project 2 - Rankine cycle Simulator

AAnjali Datar9 May 2022

Aim- To create rankine cycle simulator using matlab.

Plot graph of h-s and T-s

Explaination- The Rankine cycle is the fundamental operating cycle of all power plants where an operating fluid is continuously evaporated and condensed. The selection of operating fluid depends mainly on the available temperature range.

Rankine cycle operates on following step

1-2-3 - Isobaric Heat Transfer. High pressure liquid enters the boiler from the feed pump (1) and is heated to the saturation temperature (2). Further addition of energy causes evaporation of the liquid until it is fully converted to saturated steam (3).

3-4 Isentropic Expansion. The vapor is expanded in the turbine, thus producing work which may be converted to electricity. In practice, the expansion is limited by the temperature of the cooling medium and by the erosion of the turbine blades by liquid entrainment in the vapor stream as the process moves further into the two-phase region. Exit vapor qualities should be greater than 90%.

4-5 Isobaric Heat Rejection. The vapor-liquid mixture leaving the turbine (4) is condensed at low pressure, usually in a surface condenser using cooling water. In well designed and maintained condensers, the pressure of the vapor is well below atmospheric pressure, approaching the saturation pressure of the operating fluid at the cooling water temperature.

5-1 Isentropic Compression. The pressure of the condensate is raised in the feed pump. Because of the low specific volume of liquids, the pump work is relatively small and often neglected in thermodynamic calculations.

Back work ratio- It is the ratio of the compressor work to the turbine work in gas-turbine power plants.

Net work done-Wnet=Wturbine-Wpump

Governing Equations:

Net Work done = Wturbine -Wpump
Thermal eff = Wnet / Qin
Work ratio = Wnet-Wt
Back work ratio = Wp/Wt
WE+BWR = 1
Steam rate = 1/ Wnet

Code :

clear all

close all

clc

%program for rankin cycle simulation

%1=turbine inlet

%2= turbine oulet

%3=pump inlet

%4=pump outlet

%input parameters

%p1= turbine inlet pressure

%t1=turbine inlet temperature

%p2=Turbine outlet pressure

% Description of the process

disp('process(1-2)-isentropic expansion in turbine')

disp('process(2-3)- isobaric heat rejection')

disp('process(3-2)-isentropic compression')

disp('process(4-1)-isobaric heat addition')

%for state variable input at point 1

p1=input('enter the pressure at turbine inlet(in bar): ')

t1=input('enter the temperature at turbine inlet(in degree.C): ')

p2=input('enter the value of pressue at condenser inlet(in bar): ')

%extrating data

%state 1

h1=XSteam('h_pT',p1,t1);

s1=XSteam('s_pT',p1,t1);

%state 2

s2=s1;

sf2=XSteam('sL_p',p2);

sg2=XSteam('sV_p',p2);

x2=(s2-sf2)/(sg2-sf2);

hf2=XSteam('hL_p',p2);

hg2=XSteam('hV_p',p2);

h2=hf2+(x2*(hg2-hf2));

%state 3

p3=p2

s3=XSteam('sL_p',p3);

h3=XSteam('hL_p',p3');

%state 4

s4=s3;

p4=p1

%work done by turbine

wt=h1-h2;

%work done to run pump

v3=XSteam('vL_p',p3);

wp=v3*(p4-p3)*100;

h4=h3+wp;

%net work

wnet=wt-wp;

%heat into system

qin=h1-h4;

%heat out of system

qout=h2-h3;

%thermal efficiency

eff=(wnet/qin)*100;

%specific steam consumption

%ssc=mass flow rate/power;

ssc=(3600/wnet);

%calculating temperature at state points

t3=XSteam('Tsat_p',p3);

t2=t3;

cp4=XSteam('Cp_ps',p4,s4);

cv4=XSteam('Cv_ps',p4,s4);

k=cp4/cv4;

t4=t3/((p3/p4)^((k-1)/k));

% back work ratio

back_work_ratio=(wp/wt);

%line for plotting

t6=XSteam('Tsat_p',p1);

s5=XSteam('sL_p',p1);

s6=XSteam('sV_p',p1);

h5=XSteam('hL_p',p1);

h6=XSteam('hV_p',p1);

t5=t6;

%plotting the saturation curve

T=linspace(1,375,1000);

for i=1:length(T)

sf(i)=XSteam('sL_T',T(i));

sg(i)=XSteam('sV_T',T(i));

hf(i)=XSteam('hL_T',T(i));

hg(i)=XSteam('hV_T',T(i));

end

%plotting T-S diagram

figure(1)

hold on

plot(sf,T,'r','linewidth',1)

plot(sg,T,'r','linewidth',1)

plot([s1 s2],[t1 t2],'k','linewidth',2)

plot([s2 s3],[t2 t3],'k','linewidth',2)

plot([s3 s4],[t3 t4],'k','linewidth',2)

plot([s4 s5],[t4 t5],'k','linewidth',2)

plot([s5 s6],[t5 t6],'k','linewidth',2)

sc1=linspace(s6,s1,1000);

for l=1:length(sc1)

Tc1(l)=XSteam('T_ps',p1,sc1(l));

end

plot(sc1,Tc1,'k','linewidth',1)

text(s1+0.1,t1,'1')

text(s2+0.1,t2,'2')

text(s3,t3-20,'3')

text(s4,t4+20,'4')

title('Temp vs Entropy plot')

xlabel('Entropy,s')

ylabel('temperature')

legend('saturation curve')

%plot h-s diagram

figure(2)

hold on

plot(sf,hf,'r','linewidth',1)

plot(sg,hg,'r','linewidth',1)

plot([s1 s2],[h1 h2],'k','linewidth',2)

plot([s2 s3],[h2 h3],'r','linewidth',2)

plot([s3 s4],[h3 h4],'r','linewidth',2)

hc=linspace(h4,h5,100);

for k=1:length(hc)

sch(k)=XSteam('s_ph',p1,hc(k));

end

plot(sch,hc,'k','lineWidth',2 )

plot([s5 s6],[h5 h6],'k','linewidth',2)

for m=1:length(sc1)

hc1(m)=XSteam('h_ps',p1,sc1(m));

end

plot(sc1,hc1,'k','linewidth',2)

text(s1+0.1,h1,'1')

text(s2+0.1,h2,'2')

text(s3,h3-100,'3')

text(s4,h4+200,'4')

title('enthalpy vs entropy')

xlabel('entropy,s')

ylabel('enthalpy,h')

legend('saturation curve','location','northwest')

%Display results

disp('results')

fprintf('At state point 1: \n');

fprintf('p1 is : %f bar \n',p1);

fprintf('T1 is: %f c \n',t1);

fprintf('h1 is : %f KJ/Kg \n',h1);

fprintf('s1 is: %f kJ/kgk \n',s1);

fprintf('At state point 2: \n');

fprintf('p2 is : %f bar \n',p2);

fprintf('T2 is: %f c \n',t2);

fprintf('h2 is : %f KJ/Kg \n',h2);

fprintf('s2 is: %f kJ/kgk \n',s2);

fprintf('x2 is: %f n \n',x2);

fprintf('At state point 3: \n');

fprintf('p3 is : %f bar \n',p3);

fprintf('T3 is: %f c \n',t3);

fprintf('h3 is : %f KJ/Kg \n',h3);

fprintf('s3 is: %f kJ/kgk \n',s3);

fprintf('At state point 4: \n');

fprintf('p4 is : %f bar \n',p4);

fprintf('T4 is: %f c \n',t4);

fprintf('h4 is : %f KJ/Kg \n',h4);

fprintf('s4 is: %f kJ/kgk \n',s4);

fprintf('turbine work: %f kJ/kg \n',wt);

fprintf('pump work: %f kJ/kg \n',wp);

fprintf('wnet is: %f kJ/kg \n',wnet);

fprintf('efficiency: %f percent \n',eff);

fprintf('s.s.c: %f KJ/kg \n',ssc);

fprintf('back work ratio: %f \n',back_work_ratio);

Explanation :

To Stimulate and find out different state of variables.all the process parameters to be descibes such as all four process ocuring and input parameters.
from Xsteam library to get steam table for water
calculated points used to find net work done , themal eff , back water ratio
plot T-s and H-s Diagram

Code Inputs :

Outputs :

Project 2 - Rankine cycle Simulator

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in your own course.

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Ship work like thisin your own course.

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Ship work like this
in your own course.