Project 2 - Rankine cycle Simulator

AIM:

*To simulate the rankine cycle and plot the corresponding T-S and

H-S plot using MATLAB.

OBJECTIVE:

*Calculate the state points of the rankine cycle based on the given inputs.

*Plot the corresponding T-S and H-S plots for the given set of inputs.

INPUT VALUES:

*Turbine inlet temperature=400 degree celcius

*Turbine inlet pressure = 30 bar

*Turbine outlet pressure = 0.05 bar

INTRODUCTION:

*Rankine cycle converts thermal energy to mechanical energy.

*Onroad vehicles, which convert around one-third of the fuel energy into usefulmechanical energy for propulsion,are moving coversion system that generate considerable waste heat.

1-2: Isentropic compression in a pump

2-3: Constant pressure heat addition in a boiler

3-4: Isentropic expansion in turbine

4-1: Constant pressure heat rejection in a condenser

EXPLANATION OF THE PROGRAM :

*The program start with clear all, close all and clc command.

*We ask user for the inputs.Function input() is used to provide the user input user input includes temperature and pressure before entry to the turbine and pressure after exit to the turbine.

*Based on the user inputs parameters at 4 state points are calculated.

*Thermodynamics parameters include enthalpy H, entropy S, temperature T, pressure P, and dryness factor X at state point 2.

*Calculating these parameters XSteam().This program consist of function of all thermodynamic properties.

*After calling these function in the main script gives us thermodynamic properties based on other properties like temperature and pressure.

*After calculating all parameters , the next the next objective is calculate pump work, turbine work , net work output, back ratio , and thermal efficiency.

*We need to display all these results in command window which is done by using command ‘fprintf()’.

*Thee next objective is to plot the graph for h-s and t-s diagram.the first step in the plotting this graph is to plot the saturation curve which iscalculated using ‘for’ loop,values for entropy and enthalpy are calculated over a temperature range.Plotting these calculated values ,the plot of a saturation curve can be obtained.

*Other processes are plotted by plotting respective values of H,S,T.

*To user to continue or end the program,we have introduced a while statement at the start of the script.

*Then at the end we ask the user if wants to continue, if chooses “Y” then

The program runs again ,if he chooses “N” the program stopes.

% Printing Introduction
fprintf('RANKINE CYCLE SIMULATOR\n')
fprintf('\n1-2 is isentropic expansion in the Turbine \n')
fprintf('2-3 is Constant Pressure Heat Rejection by the Condensor\n')
fprintf('3-4 is isentropic Compression in pump \n')
fprintf('4-1 is constant Pressure Heat Addition by the boiler \n')

% User Inputs
P1=input('\nEnter the Pressure at the Turbine Inlet(in bar):');
T1=input('Enter the Temperature at the Turbine Inlet(in Degree Celcius):');
P2=input('Enter the Pressure at the Turbine Outlet(in bar):');

%State point 1
H1=XSteam('h_pt',P1,T1);   %Enthalpy
S1=XSteam('s_pt',P1,T1);   %Entropy
Hf1=XSteam('hL_p',P1);     %Enthalpy of saturated liquid
Hg1=XSteam('hV_p',P1);     %Enthalpy of saturated vapour
Ts1=XSteam('Tsat_p',P1);   %Saturation Temperature
Sf1=XSteam('sL_p',P1);     %Entropy of saturated liquid
Sg1=XSteam('sV_p',P1);     %Entropy of saturated vapour

%State point 2
S2=S1;
Sf2=XSteam('sL_p',P2);
Sg2=XSteam('sV_p',P2);
x = (S2-Sf2)/(Sg2-Sf2);    %Dryness fraction
Hf2=XSteam('hL_p',P2);
Hg2=XSteam('hV_p',P2);
H2=Hf2 + x*(Hg2-Hf2);
T2 = XSteam('T_ph',P2,H2);
Ts2=XSteam('Tsat_p',P2);

%State point 3
H3=Hf2;
S3=Sf2;
T3=T2;
P3=P2;

%State point 4
P4=P1;
S4=S3;
H4=XSteam('h_ps',P4,S4);
T4=XSteam('T_ps',P4,S4);

t = linspace(0,374,500);    % temp space for plotting saturation curve

%Plot T-S Diagram
figure(1)
hold on 
%Plotting Saturation Curve
for i = 1 :length(t)
    plot(XSteam('sL_T',t(i)),t(i),'.','color','b')
    plot(XSteam('sV_T',t(i)),t(i),'.','color','b')
end
%Plot Cycle
plot([S1 S2],[T1 T2],'linewidth',2,'color','r')
if x>1
    T3 = Ts2;
    plot([S2 Sg2 S3 S4],[T2 Ts2 T3 T4],'linewidth',2,'color','r')
    T2 = Ts2;
else
    plot([S2 S3 S4],[T2 T3 T4],'linewidth',2,'color','r')
end
l= linspace(T1,T2,1000);
for i =1:length(l)
    plot(XSteam('s_pT',P1,l(i)),l(i),'.','color','r')
end
plot([Sf1 Sg1],[Ts1 Ts1],'linewidth',2,'color','r')
xlabel('Entropy[KJ/Kg-K]')
ylabel('Temperature[K]')
title('T-S Diagram')

% Plot H-S Diagram
figure(2)
hold on
%Plot Saturation Curve 
for i = 1:length(t)
    plot(XSteam('sL_T',t(i)),XSteam('hL_T',t(i)),'.','color','b')
    plot(XSteam('sV_T',t(i)),XSteam('hV_T',t(i)),'.','color','b')
end

%Plot Cycle
plot([S1 S2 S3 S4 S1],[H1 H2 H3 H4 H1],'linewidth',2,'color','r')
xlabel('Entropy[KJ/Kg-K]')
ylabel('Enthalpy[KJ/Kg]')
title('H-S Diagram')


% calculations
%Turbine Work
Wt= H1-H2;

%Pump Work
Wp = H4-H3;

%Heat addition
Qin=H1-H4;
%Heat Rejection
Qout=H2-H3;

%Net Work
Wnet=Wt-Wp;

%Efficiency
Ntherm = (Wnet/Qin)*100;
%Specific steam consumption
SSC = 3600/Wnet;
%Back Work Ratio
BWR = Wp/Wt;

%Print Results
fprintf('\n\nResults\n')
fprintf('At State Point 1:\n')
fprintf('P1 is :%.2f bar\n',P1)
fprintf('T1 is :%.2f Deg Celcius\n',T1)
fprintf('H1 is :%.2f KJ/Kg\n',H1)
fprintf('S1 IS :%.2f KJ/Kg-K\n',S1)


fprintf('\nAt State Point 2:\n')
fprintf('P2 is :%.2f bar\n',P2)
fprintf('T2 is :%.2f Deg Celcius\n',T2)
fprintf('H2 is :%.2f KJ/Kg\n',H2)
fprintf('S2 is :%.2f KJ/Kg-K\n',S2)

fprintf('\nAt State Point 3:\n')
fprintf('P3 is :%.2f bar\n',P3)
fprintf('T3 is :%.2f Deg Celcius\n',T3)
fprintf('H3 is :%.2f KJ/Kg\n',H3)
fprintf('S3 is :%.2f KJ/Kg-K\n',S3)


fprintf('\nAt State Point 4:\n')
fprintf('P4 is :%.2f bar\n',P4)
fprintf('T4 is :%.2f Deg Celcius\n',T4)
fprintf('H4 is :%.2f KJ/Kg\n',H4)
fprintf('S4 is :%.2f KJ/Kg-K\n',S4)


fprintf('\nWt is : %.2f KJ/Kg\n',Wt)
fprintf('Wp is : %.2f KJ/Kg\n',Wp)
fprintf('Wnet is : %.2f KJ/Kg\n',Wnet)
fprintf('Thermal Efficiency is : %.2f percent\n',Ntherm)
fprintf('S.S.C. is :%.2f Kg/KWh\n',SSC)
fprintf('Back Work Ratio is : %.3f\n',BWR)