The gas-turbine cycle of a combined gas-steam power plant has a pressure ratio of 12. Air enters the compressor at 310 K and the turbine at 1400 K. The combustion gases leaving the gas turbine are used to heat the steam at 12.5 MPa to 500°C in a heat exchanger. The combustion gases leave the heat exchanger at 2478C. Steam expands in a high-pressure turbine to a pressure of 2.5 MPa and is reheated in the combustion chamber to 550°C before it expands in a low-pressure turbine to 10 kPa. The mass flow rate of steam is 12 kg/s. Assuming all the compression and expansion processes to be isentropic, determine (a) the mass flow rate of air in the gas-turbine cycle. (b) the rate of total heat input, and (c) the thermal efficiency of the combined cycle.

The gas-turbine cycle of a combined gas-steam power plant has a pressure ratio of 12. Air enters the compressor at 310 K and the turbine at 1400 K. The combustion gases leaving the gas turbine are used to heat the steam at 12.5 MPa to 500°C in a heat exchanger. The combustion gases leave the heat exchanger at 2478C. Steam expands in a high-pressure turbine to a pressure of 2.5 MPa and is reheated in the combustion chamber to 550°C before it expands in a low-pressure turbine to 10 kPa. The mass flow rate of steam is 12 kg/s. Assuming all the compression and expansion processes to be isentropic, determine (a) the mass flow rate of air in the gas-turbine cycle. (b) the rate of total heat input, and (c) the thermal efficiency of the combined cycle.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

Superheated steam generated in a power plant at a pressure of 8,600 kPa anda temperature of 500 ℃ is fed to a turbine. Exhaust from the turbine enters acondenser at 15 kPa, where it is condensed to saturated liquid, which is thenpumped to the boiler.(a) What is the thermal efficiency of a Rankine cycle operating at theseconditions?(b) What is the thermal efficiency of a practical cycle operating at theseconditions if the turbine efficiency and pump efficiency are both 75%?Which of the two efficiencies has greater impact on the thermal efficiency?(c) Sketch both cycles in the same T-s diagram.(d)If the power output of the turbine is 80,000 kW in case (b), calculate themass flow rate of the working fluid.(e) Calculate the heat transfer rates in the boiler and the condenser. Doublecheck the result for the condenser.(f) For both cases (a) and (b), make a comment about the operation of turbine(issue of cavitation). [one sentence is fine](g) How you would operate the condenser of a practical…
QII/ The gas-turbine portion of a combined gas—steam power plant has a pressure ratio of 16. Air enters the compressor at 300 K at a rate of 14 kg/s and is heated to 1500 K in the combustion chamber. The combustion gases leaving the gas turbine are used to heat the steam to 400 0 C at 10 MPa in a heat exchanger. The combustion gases leave the heat exchanger at 420 K. The steam leaving the turbine is condensed at 15 kPa. Assuming all the compression and expansion processes to be isentropic, determine (a) the mass flow rate of the steam, (b) the net power output, and (c) the thermal efficiency of the combined cycle. For air, assume constant specific heats at room temperature. Answers:(a) 1.275 kg/s, (b) 7819 kW, (c) 66.4 percent.
In a gas turbine generating set two stages of compression are used with an intercooler between stages. The HP turbine drives the HP compressor, and the LP turbine drives the LP compressor and the generator. The exhaust from the LP turbine through a heat exchanger which transfer heat to the air leaving the HP compressor. There is a reheat combustion chamber between turbine stages which raises the gas temperature to 8000C, which is also the gas temperature at entry to the HP turbine. The overall pressure ratio is 30, each compressor having the same pressure ratio, and the air temperature at entry to the unit is 300C. The heat exchanger thermal ratio may be taken as 0.75, and intercooling is complete between compressor stages. Assume isentropic efficiencies of 0.85 for both compressor stages, and 0.9 for both turbine stages, and the 4% of the work of each turbine is used in overcoming friction. Neglecting the losses in pressure, and assuming that velocity changes are negligibly small,…
A gas turbine power plant operates on a simple thermodynamic cycle. The ambient conditionsare 100 kPa and 24 °C. The air at this condition enters the engine at 150 m/s whose diameteris 0.5 m. The pressure ratio across the compressor is 18 k and the temperature at the turbineinlet is 1400 K. Assuming ideal operation for all components and specific heats for air andproducts separately. In addition, neglect the mass of fuel burned. Do the followings:a. Choose the suitable thermodynamic cycleb.Draw pv and Ts diagram and label itCalculate the power required by the compressordDetermine the pressure and the temperature at the turbine exit,Compute the power produced by the turbinef.Available specific workg.The thermal efficiency
In a gas turbine plant, the pressure ratio, through which air at 15°C is compressed, is 6. The same air is then heated to a maximum permissible temperature of 750°C first in a heat exchanger which is 75% efficient and then in the combustion chamber. The same air at 750 C is expanded in two stages such that expansion work is maximum. The air is reheated to 750°C after the first state. Determine the cycle thermal efficiency, the work ratio and the net shaft work per kg of air. The efficiencies may be assumed to be 80% and 85% for the compressor and turbine respectively.e) Air enters the compressor of a gas turbine
A gas turbine power plant operates on a simple thermodynamic cycle. The ambient conditionsare 100 kPa and 24 °C. The air at this condition enters the engine at 150 m/s whose diameteris 0.5 m. The pressure ratio across the compressor is 19, and the temperature at the turbineinlet is 1400 K. Assuming ideal operation for all components and specific heats for air andproducts separately. In addition, neglect the mass of fuel burned. Do the followings:a. Choose the suitable thermodynamic cycleb. Draw pv and Ts diagram and label itc. Calculate the power required by the compressord. Determine the pressure and the temperature at the turbine exit,e. Compute the power produced by the turbinef. Available specific workg. The thermal efficiency
A steam Rankine cycle operates between the pressure limits of 1500 psia in the boiler and 2 psia in the condenser. The turbine inlet temperature is 800F. The turbine isentropic efficiency is 90 percent, the pump losses are negligible, and the cycle is sized to produce 2500 kW of power. Calculate the mass flow rate through the boiler, the power produced by the turbine, the rate of heat supply in the boiler, and the thermal efficiency.
TNB steam power plant in Genting Highlandsoperates on reheat Rankine cycleand has power net output of 50MW. Steam enters the turbine at aMPa and b °Cand it is cooled in the condenser at a pressure of ckPa by running cooling water from the Bertam River through the tubesof condenser. Steam enters both stages of the turbine at b°C. If the moisture content of the steam at the exit of the low-pressure turbine is not to exceed 10 percent, show the cycle on a T-s diagram and determine;i.The pressure at which reheating takes place, ii.The thermal efficiency of the cycleandiii.Please justify how does the thermal efficiency of the cycle if the temperature to low turbine is increase to 600°C? a=12 b=500 c=12
Q4) Steam generated in a power plant at a pressure of 5500 kPa and a temperature of 420°C is fed to a turbine. Exhaust from the turbine enters a condenser at 20 kPa where it is condensed to saturated liquid, which then pumped to the boiler. Determine the thermal efficiency of a Rankin cycle operating at these conditions.
A gas turbine power plant operates on a simple thermodynamic cycle. The ambient conditionsare 100 kPa and 24 °C. The air at this condition enters the engine at 150 m/s whose diameteris 0.5 m. The pressure ratio across the compressor is 11, and the temperature at the turbineinlet is 1400 K. Assuming ideal operation for all components and specific heats for air andproducts separately. In addition, neglect the mass of fuel burned. Do the followings:a. Compute the power produced by the turbineb Available specific workc. The thermal efficiency.
A gas turbine power plant operates on a simple thermodynamic cycle. The ambient conditionsare 100 kPa and 24 °C. The air at this condition enters the engine at 150 m/s whose diameteris 0.5 m. The pressure ratio across the compressor is 11, and the temperature at the turbineinlet is 1400 K. Assuming ideal operation for all components and specific heats for air andproducts separately. In addition, neglect the mass of fuel burned. Do the followings:a. Choose the suitable thermodynamic cycleb. Draw pv and Ts diagram and label itc. Calculate the power required by the compressord. Determine the pressure and the temperature at the turbine exit,e. Compute the power produced by the turbinef. Available specific workg. The thermal efficiency. Explain with clear writing and units and diagram Also if you use tables and equation mention it with explanation
Problem 1: The boiler of a power steam cycle operates at 6000 kPa and the condenser at 50 kPa. At the entrance to the turbine, the temperature is 500°C. The isentropic efficiency of the turbine is 90 percent, pressure and pump losses are negligible, and the water leaving the condenser is subcooled by 6.3°C. The boiler is sized for a mass flow rate of 18 kg/s. You are asked to: a. Represent the cycle on P-v and T-s diagrams. b. Compute the rate at which heat is added in the boiler. c. Compute the power required to operate the pumps. d. Determine the net power produced by the cycle. e. Compute the thermal efficiency.