Consider combined gas-steam power cycle. The topping cycle is a gas-turbine cycle that has a pressure

ratio of rp. Air enters the compressor at T'₁ and the turbine at T'3. The isentropic efficiency of the

compressor is 80 percent, and that of the gas turbine is 85 percent. The bottoming cycle is a simple ideal

Rankine cycle operating between the pressure limits of PH and P₁. Steam is heated in a heat exchanger

by the exhaust gases to a temperature of 500°C. The exhaust gases leave the heat exchanger at 450 K.

Assume variable specific heats (You have to solve the problem using Thermodynamic Tables).

- Requirements:

- You are required to perform the following steps:

1) Calculate the following based on your group assigned data as shown in in the Table in Part (C)

Groups Distribution.

(a) the ratio of the mass flow rates of the steam and the combustion gases.

(b) The heat input and work output.

(c) The thermal efficiency of the combined cycle.

2) Consider the following modifications and repeat task (1) accordingly:

i. The gas-turbine cycle has ideal two-stage compression (intercooling) and two-stage expansion

(reheating).

ii. The steam Rankine cycle has ideal reheat stage (reheat pressure = 2 MPa, temperature = 500°C).

iii. The steam Rankine cycle has ideal regeneration stage (Open Feedwater Heater) with

regeneration pressure of 1 MPa.

iv. Only for Group (1), the gas turbine has ideal regeneration stage (100% effectiveness).