Project 2 - Rankine cycle Simulator

Processes in Rankine Cycle :-

There are four processes in the Rankine cycle. These states are identified by numbers (in brown) in the above T-s diagram.

Process 1-2: The working fluid is pumped from low to high pressure. As the fluid is a liquid at this stage, the pump requires little input energy.

Process 2-3: The high-pressure liquid enters a boiler, where it is heated at constant pressure by an external heat source to become a dry saturated vapour. The input energy required can be easily calculated graphically, using an enthalphy-entropy chart, or Mollier Diagram, or numerically, using steam tables

Process 3-4: The dry saturated vapour expands through a turbine, generating power. This decreases the temperature and pressure of the vapour, and some condensation may occur. The output in this process can be easily calculated using the chart or tables noted above.

Process 4-1: The wet vapour then enters a condenser, where it is condensed at a constant pressure to become a saturated liquid.

Main Code :-

clear all 
close all
clc


% Simulatig Rankine Cycle
% Process Description
fprintf('1-2 Isobaric heat Transfer\n')
fprintf('2-3 Isentropis Expansion\n')
fprintf('3-4 Isobaric heat Rejection\n')
fprintf('4-1 Isentropic Compression')

% Inputs
p1 = input('Enter the Pressure at turbine inlet(in bar):');
t1 = input('Enter the Temperature at the Inlet(in Degree Celcious):');
p2 = input('Enter the Pressure at the Condenser(in bar):');

% Input Conditions
t = XSteam('Tsat_p',p1);
if t >= t
h1 = XSteam('h_pT',p1,t1);
s1 = XSteam('s_pT',p1,t1);
% State points Evaluation
p4 = p1;
p3 = p2;
h3 = XSteam('hL_p',p3);
s3 = XSteam('sL_p',p3);
t3 = XSteam('Tsat_p',p3);
s2 = s1;
t2 = t3;
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);
s4 = s3;
h4 = XSteam('h_ps',p4,s4);
cp4 = XSteam('Cp_ps',p4,s4);
cv4 = XSteam('Cv_ps',p4,s4);
g4 = cp4/cv4;
o = (g4 - 1)/g4;
t4 = t3*((p4/p3)^o);

% Turbine & Pump Work
wt = h1 - h2;
wp = h4 - h3;
% net work
wnet = wt - wp;
% heat supplied
qs = h1 - h4;
% Efficiency
n_per = (wnet/qs)*100;
% Steam rate per second
stm_rate = 3600/(wt - wp);

% For process 4-1, which is isobaric we use the expression dH = Cp*dT
t5 = XSteam('Tsat_p',p1);
s5 = XSteam('sL_p',p1);
s6 = XSteam('sV_p',p1);

% output
fprintf('\n\tRESULT\n')
fprintf('At State point 1:\nP1 is :%4.2f Bar\nT1 is :%4.2f Degree Celcius\nH1 is :%4.2f kJ/kg\nS1 is :%4.2f kJ/kgk\n\n',p1,t1,h1,s1)
fprintf('At State point 2:\nP2 is :%4.2f Bar\nT2 is :%4.2f Degree Celcius\nH2 is :%4.2f kJ/kg\nS2 is :%4.2f kJ/kgk\n\n',p2,t2,h2,s2)
fprintf('At State point 3:\nP3 is :%4.2f Bar\nT3 is :%4.2f Degree Celcius\nH3 is :%4.2f kJ/kg\nS3 is :%4.2f kJ/kgk\n\n',p3,t3,h3,s3)
fprintf('At State point 4:\nP4 is :%4.2f Bar\nT4 is :%4.2f Degree Celcius\nH4 is :%4.2f kJ/kg\nS4 is :%4.2f kJ/kgk\n\n',p4,t4,h4,s4)
fprintf('Wt is :%4.2f kJ/kg\nWp is :%4.2f kJ/kg\nWnet is :%4.2f kJ/kg\nNtherm is :%4.2f percent\nS.S.C is :%4.2f kg/kWh',wt,wp,wnet,n_per,stm_rate)

% Vapour line
temp = linspace(1,400,100);
for i = 1:length(temp)
    ent_l(i) = XSteam('sL_T',temp(i));
    ent_v(i) = XSteam('sV_T',temp(i));
    enth_l(i) = XSteam('hL_T',temp(i));
    enth_v(i) = XSteam('hV_T',temp(i));
end

% Plotting
subplot(1,2,1)
plot([s1 s2 s3 s4 s5 s6 s1],[t1 t2 t3 t4 t5 t5 t1],'Color','k','linewidth',2,'marker','o','markersize',2,'markerfacecolor','b','markeredgecolor','b')
hold on
plot(ent_l,temp,'Color','g')
plot(ent_v,temp,'color','g')
axis([0 10 0 700])
text(s1,t1,'1','FontSize',15)
text(s2,t2,'2','FontSize',15)
text(s3,t3,'3','FontSize',15,'HorizontalAlignment','right')
text(s4,t4,'4','FontSize',15,'HorizontalAlignment','right')
xlabel('Entropy')
ylabel('Temperature')
subplot(1,2,2)
plot([s1 s2 s3 s4 s1],[h1 h2 h3 h4 h1],'Color','k','linewidth',2,'marker','o','markersize',2,'markerfacecolor','b','markeredgecolor','b')
axis([0 10 300 5000])
hold on
plot(ent_v,enth_v,'color','g')
plot(ent_l,enth_l,'color','g')
text(s1,h1,'1','FontSize',15)
text(s2,h2,'2','FontSize',15)
text(s3,h3,'3','FontSize',15,'HorizontalAlignment','right','VerticalAlignment','top')
text(s4,h4,'3','FontSize',15,'HorizontalAlignment','right','VerticalAlignment','bottom')
xlabel('Entropy')
ylabel('Enthalpy')    

else
    fprintf('Enter Temperature Greater or Equal to Saturation Temperature')
end    

Result :-

Output - figure

Command Window

1-2 Isobaric heat Transfer
2-3 Isentropis Expansion
3-4 Isobaric heat Rejection
4-1 Isentropic CompressionEnter the Pressure at turbine inlet(in bar):30
Enter the Temperature at the Inlet(in Degree Celcious):400
Enter the Pressure at the Condenser(in bar):0.05

	RESULT
At State point 1:
P1 is :30.00 Bar
T1 is :400.00 Degree Celcius
H1 is :3231.57 kJ/kg
S1 is :6.92 kJ/kgk

At State point 2:
P2 is :0.05 Bar
T2 is :32.88 Degree Celcius
H2 is :2110.71 kJ/kg
S2 is :6.92 kJ/kgk

At State point 3:
P3 is :0.05 Bar
T3 is :32.88 Degree Celcius
H3 is :137.77 kJ/kg
S3 is :0.48 kJ/kgk

At State point 4:
P4 is :30.00 Bar
T4 is :36.94 Degree Celcius
H4 is :140.76 kJ/kg
S4 is :0.48 kJ/kgk

Wt is :1120.86 kJ/kg
Wp is :3.00 kJ/kg
Wnet is :1117.87 kJ/kg
Ntherm is :36.17 percent
S.S.C is :3.22 kg/kWh

Workspace