Project 2 - Rankine cycle Simulator
The Rankine cycle is an ideal thermodynamic cycle involving a constant pressure heat engine which converts heat into mechanical work. The heat is supplied externally in this cycle in a closed loop, which uses either water or any other organic fluids (Pentane or Toluene) as a working fluid.
The process in Rankine cycle are given as:
1. Isentropic Compression in Pump.
2. Constant pressure heat addition in boiler.
3. Isentropic expansion in a turbine.
4. Constant pressure heat rejection in condenser.
MAIN PROGRAM:
clear all %delete all varibles
close all %delete all plots
clc %clear command wondow
% Rankine Cycle Simulator
fprintf('Rankine Cycle\n ')
fprintf('1-2 is Isentropic Expansion in Turbine\n')
fprintf('2-3 is constant pressure heat removal\n')
fprintf('3-4 is Isentropic Compression in Pump \n')
fprintf('4-1 Constant pressure Heat addition in Boiler\n')
%Taking input from user
p1 = input('Enter the Value of pressure at turbine inlet, p1(in bar) = ');
T1 = input('Enter the Value of temperature at turbine inlet, T1(in degree C) = ');
p2 = input('Enter the Value of pressure at condenser inlet, p2(in bar) = ');
% Input data for calculation of state points
p1 = 30; %Pressure at Turbine Inlet
T1 = 400; %Temperature at Turbine Inlet
p2 = 0.05; %Pressure at Condenser
% Taking data from Xsteam file for State point 1
h1 = XSteam('h_pT', p1, T1); % Enthaply at p1 and T1
s1 = XSteam('s_pT', p1, T1); % Entropy at p1 and T1
% Extracting data from Xsteam file for State point 2
s2 = s1; % Isentropic Expansion
sf2 = XSteam('sL_p', p2); % Saturated liquid entropy at p2
sg2 = XSteam('sV_p', p2); % Saturated vapour entropy at p2
x2 = (s2-sf2)/(sg2-sf2); % Vapour Fraction at state point 2
hf2 = XSteam('hL_p', p2); % Saturated liquid Enthalpy at p2
hg2 = XSteam('hV_p', p2); % Saturated vapour Enthalpy at p2
h2 = hf2 + (x2*(hg2-hf2)); % Enthalpy at state point 2
% Extracting data from Xsteam file for state point 3
p3 = p2; % Constant Pressure heat removal process
s3 = XSteam('sL_p', p3); % Saturated liquid entropy at P3
h3 = XSteam('hL_p', p3); % Saturated liquid Enthalpy at P3
% Extracting data from Xsteam file for State point 4
s4 = s3; % Isentropic Compression process
p4 = p1; % Constant Pressure heat rejection
% Work done in Turbine for the rankine cycle
W_T = h1-h2;
% Work done required for pump
v3 = XSteam('vL_p',p3); % Saturated Liquid Vapour at p3
W_P = v3*(p4-p3)*100; % Work done for pump
h4 = h3 - W_P; % Enthalpy at State point 4
% Net work done for Rankine Cycle
W_net = W_T - W_P;
% Heat Addition to System
Q_in = h1-h4;
% Heat Rejection from System
Q_out = h2-h3;
% Thermal Efficiency of Rankine Cycle
T_eff = (W_net/Q_in)*100;
%Specific steam consumption = (Mass flow rate / Net work done)
Sp_S = (3600/W_net);
% Calculation of Temperature at All state Point 2, 3 and 4
T3 = XSteam('Tsat_p',p3); % Saturation Temperature at P3
T2 = T3; % Becuase of Constant Pressure Heat addition
Cp4 = XSteam('Cp_ps',p4,s4); % Specific isobaric heat capacity
Cv4 = XSteam('Cv_ps',p4,s4); % Specific isochoric heat capacity
k = Cp4/Cv4;
T4 = T3/((p3/p4)^((k-1)/k)); % Temperature at State point 4
% Calculation of Other constant for saturated liquid and Vapour
T6 = XSteam('Tsat_p', p1); % Saturated Temperature at p1
s5 = XSteam('sL_p', p1); % Saturated Liquid entropy at p1
s6 = XSteam('sV_p', p1); % Saturated Vapour entropy at P1
h5 = XSteam('hL_p', p1); % Saturated Liquid Enthalpy at p1
h6 = XSteam('hV_p', p1); % Saturated Vapour Enthalpy at p1
T5 = T6;
%Plotting for Saturation Line
T = linspace(1,560,1000);
for i = 1:length(T)
sf(i) = XSteam('sL_T' ,T(i)); % Saturated Liquid Entropy
sg(i) = XSteam('sV_T' ,T(i)); % Saturated Vapour Entropy
hf(i) = XSteam('hL_T' ,T(i)); % Saturated Liquid Enthalpy
hg(i) = XSteam('hV_T' ,T(i)); % Saturated Vapour Enthalpy
end
% Plotting T-S Diagram
figure(1)
hold on
plot(sf,T,'color','b','linewidth',2)
plot(sg,T,'color','b','linewidth',2)
plot([s1 s2],[T1 T2], 'color', 'r', 'linewidth',3)
plot([s2 s3],[T2 T3], 'color', 'r', 'linewidth',3)
plot([s3 s4],[T3 T4], 'color', 'r', 'linewidth',3)
plot([s4 s5],[T4 T5], 'color', 'r', 'linewidth',3)
plot([s5 s6],[T5 T6], 'color', 'r', 'linewidth',3)
s_1 = linspace(s6,s1,1000);
for j = 1:length(s_1)
Tc(j) = XSteam('T_ps',p1,s_1(j));
end
plot(s_1,Tc,'color','r','linewidth',3)
text(s1+0.1, T1, '1')
text(s2+0.1, T2, '2')
text(s3, T3-20, '3')
text(s4, T4+20, '4')
title('Temperature Vs Entropy')
xlabel('Entropy (Kj/kg-k)')
ylabel('Temeperature (Deg. Celcius)')
legend('Saturation Curve')
% Plotting H-S Diagram
figure(2)
hold on
plot(sf,hf,'color','b','linewidth',2)
plot(sg,hg,'color','b','linewidth',2)
plot([s1 s2],[h1 h2],'color','r','linewidth',3)
plot([s2 s3],[h2 h3],'color','r','linewidth',3)
plot([s3 s4],[h3 h4],'color','r','linewidth',3)
hc = linspace(h4,h5,100);
for k = 1:length(hc)
s_c(k) = XSteam('s_ph',p1,hc(k));
end
plot(s_c,hc,'color','r','linewidth',3)
plot([s5 s6],[h5 h6],'color','r','linewidth',3)
for l = 1:length(s_1)
h_c(l) = XSteam('h_ps',p1,s_1(l));
end
plot(s_1,h_c,'color','r','linewidth',3)
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 (Kj/kg-k)')
ylabel('Enthalpy (KJ/Kg)')
legend('Saturation Curve')
% Displaying Results in Command window
disp('Results of Rankine Cycle')
fprintf('At state point 1\t\t\t\t\t')
fprintf('At state Point 2\n')
fprintf('P1 = %10f in Bar\t\t\t\t',p1);
fprintf('P2 = %10f in Bar\n',p2);
fprintf('T1 = %11f in Deg.Celcius\t\t',T1);
fprintf('T2 = %11f in Deg.Celcius\n',T2);
fprintf('H1 = %12f in KJ/Kg\t\t\t',h1);
fprintf('H2 = %12f in KJ/Kg\n',h2);
fprintf('S1 = %9f in KJ/Kg-k\t\t\t',s1);
fprintf('S2 = %9f in KJ/Kg-k\n',s2);
fprintf('\n')
fprintf('At state point 3\t\t\t\t\t')
fprintf('At state Point 4\n')
fprintf('P3 = %10f in Bar\t\t\t\t',p3);
fprintf('P4 = %10f in Bar\n',p4);
fprintf('T3 = %11f in Deg.Celcius\t\t',T3);
fprintf('T4 = %11f in Deg.Celcius\n',T4);
fprintf('H3 = %12f in KJ/Kg\t\t\t',h3);
fprintf('H4 = %12f in KJ/Kg\n',h4);
fprintf('S3 = %9f in KJ/Kg-k\t\t\t',s3);
fprintf('S4 = %9f in KJ/Kg-k\n',s4);
fprintf('\n')
fprintf('Turbine Work Done = %14f in KJ/Kg\n',W_T)
fprintf('Pump Work Done = %15f in KJ/Kg\n',W_P)
fprintf('Net Work Done = %17f in KJ/Kg\n',W_net)
fprintf('Thermal Efficiency = %13f in percent\n',T_eff)
fprintf('Sp. Steam Consumption = %f in KJ/Kw\n',Sp_S)Code Explanation:
1. Rankine cycle simulator creation starts with some input value which are required to calculate the other state point in cycle.
2. The input requires are Pressure (in bar) at state point 1 (turbine inlet), Temperature at same point (degree celcius) and pressure at condenser inlet (point 2).
3. Then inputs are entered which are inlet pressure for turbine, temperature at turbine inlet and pressure at condenser.
4. First, we get the value of enthalpy and entropy at state point 1 from the XSteam function file.
5. Process 1-2 is isentropic compression the entropy at point 1 is equal to point 2. Entropy at pressure and temperature point 1 is represented by ‘(s_pT, p1, T1)’.
6. The term saturated liquid reffered by 'sg' and saturated vapor entropy reffered by 'sf' respectively. These values are used to calculate other function.
7. Similarly, other points are taken from XSteam function file. After that work done in turbine and pump are calculated for further getting the net work done Rankine cycle.
8. The efficiency of the Rankine cycle is calculated along with specific steam consumption which is steam consumed by a locomotive cylinders per unit of output of work done.
9. Then Inputs values and data taken from XSteam file used to calculate the temperature at each point of cycle. For given temperature range from lower to higher entropy points are calculated to create the T-S plot. Similarly, another for loop is used to create the saturation curve in each plot.
10. Plotting is completed for T-s (Temperature Vs Entropy) and H-s (EnthalpyVs Entropy) graph in Rankine cycle and each state point value has been put in command window.
The input, ouput screen and the various state points with different parameters generated in the command window are shown below:
PLOT: Temperature Vs Entropy
PLOT: EnthalpyVs Entropy
OUTPUT command window:
