Project 2 - Rankine cycle Simulator

AIM: Write a program in MATLAB for Rankine cycle simulation.

RANKINE CYCLE

The Rankine cycle is a model used to predict the performance of systems. It was also used to study the performance of reciprocating steam engines. There are four processes in the Rankine cycle. 

<!--[if !supportLists]-->·         <!--[endif]-->Process 1–2: The dry saturated vapour expands through a turbine, generating power. This decreases the temperature and pressure of the vapour, and some condensation may occur. In other words, Process 3-4 is Isentropic expansion.

<!--[if !supportLists]-->·         <!--[endif]-->Process 2–3: The wet vapour then enters a condenser, where it is condensed at a constant pressure to become a liquid. In other words, Process 4-1 is Constant pressure heat rejection in condenser.

<!--[if !supportLists]-->·         <!--[endif]-->Process 3–4: 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. In other words, Process 1-2 is Isentropic compression.

<!--[if !supportLists]-->·         <!--[endif]-->Process 4-1: 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. In other words, Process 2-3 is Constant pressure heat addition in boiler.

FORMULA USE FOR THE CALCULATION

<!--[if !supportLists]-->1.      <!--[endif]-->Turbine work, Wt = H₁-H₂

<!--[if !supportLists]-->2.      <!--[endif]-->Pump work, W_p = H₄-H₃

<!--[if !supportLists]-->3.      <!--[endif]-->Heat addition Q_in = H₁-H₄

<!--[if !supportLists]-->4.      <!--[endif]-->Heat rejection Q_out = H₃-H₂

<!--[if !supportLists]-->5.      <!--[endif]-->Efficiency

<math>η=(Wt−Wp)/Qinη=(W_t-W_p)/Q_in </math>                    η=(Wt​−Wp​)/Qi​n

<!--[if gte msEquation 12]>η=Wt-WpQin<![endif]--><!--[if !msEquation]--> <!--[endif]-->

<!--[if !supportLists]-->6.      <!--[endif]-->Back-work ratio

                     <math>BWR=Wp/WtBWR=W_p/W_t </math>BWR=Wp​/Wt​

<!--[if gte msEquation 12]>BWR=WpWt<![endif]--><!--[if !msEquation]--> <!--[endif]-->

<!--[if !supportLists]-->7.      <!--[endif]-->Specific steam consumption

<math>SSC=3600/(Wt−Wp)SSC=3600/(W_t-W_p )</math>                      SSC=3600/(Wt​−Wp​)

STEP-WISE EXPLANATION OF CODE FOR FIND THE MAXIMA OF STALAGMITE FUNCTION:

1. First, I will print the general information regarding the Rankine cycle like process occurs in Rankine cycle.
2. I take the inputs like turbine inlet pressure(P₁) and temperature(T₁) and turbine outlet pressure(P₂).
3. Then we calculate the state point variable which is specific enthalpy(H), specific entropy(S) at each point with the help of Xsteam subfunction.
4. For point 2, we calculate the dryness fraction with this formula.<!--[if gte msEquation 12]>   x=S2-Sf2Sg2-Sf2<![endif]--><!--[if !msEquation]--> <!--[endif]-->.
5. We have to plot the saturation curve for T-S diagram so we use for loop to calculate the specific entropy at each temperature range. (For water the critical temperature is 374̊ C)
6. Then we plot line to connect the S₁ and S₂ point.
7. Then we use IF command for the dryness fraction greater than 1. So, if dryness fraction greater than 1 than we plot the right curve.
8. We plot the line to connect the state point 2,3 and 4.
9. To connect the state-point 4 and 1 we have to use for loop because it is not connected by the straight line.so we calculate the specific entropy at each temperature which is lies between T₄ and T₁. So, we get the complete T-S diagram.
10. For plotting H-S diagram first we plot the saturation curve for H-S diagram with help of for loop to calculate the specific enthalpy at each temperature value.
11. Then we plot the line to connect the state points.
12. We have to calculate turbine work, pump work, heat addition and heat rejection to find efficiency of the cycle.
13. We also calculate the back-work ration and specific steam consumption with help of formula.
14. Then we print the variable at each point in command window and we also print the turbine work, pump work, efficiency, etc.

MAIN PROGRAM

I attached the main program file with this challenges.
OUTPUT OF PROGRAM
GRAPH

1.T-S Diagram


2.H-S Diagram