Gas Turbine Problems
2
Gas Turbine Problems Summer 2013 1. A gas turbine unit has a pressure ratio of 6 and maximum cycle temperature of 610˚C. The isentropic efficiency of the turbine and compressor are 0.82 and 0.8 respectively. Calculate the power output in KW when the air enters the compressor at 15˚C at a rate of 16 kg/s. Take Cp= 1.005 KJ/kg K and γ = 1.4 for compression process and Cp= 1.11 KJ/kg K and γ = 1.333 for expansion process. Winter 2012 2. Calculate the efficiency and specific work output of a simple gas turbine plant operating on Brayton cycle. The maximum and minimum temperatures are 1000K and 288K respectively. The pressure ratio is 6.The isentropic efficiency of the compressor and turbines are 85% and 90% respectively. If the unit consumes 2 tonnes of oil per hour of calorific value 46500 KJ per kg, determine the power generated .The mechanical efficiency is 905 and generation efficiency is 85%. May/June 2012 3. In an open gas turbine plant, the pressure ratio through which air at 15 ˚C is compressed is 14. The same air is then heated to a maximum permissible temperature of 1300 ˚C first in a heat exchanger which is 75% efficient, and then in the combustion chamber. The air at 1300 ˚C is expanded in two stages such that the expansion work is the maximum. The air is heated to 1300˚C after the high pressure stage. Determine the cycle thermal efficiency, the work ratio and the net shaft work per kg of air. The isentropic efficiencies may be assumed to be 85% and 86% for compressor and turbine respectively. Calculate the flow rate of air for an output of 240 MW. Assume Mechanical and Generator efficiency 90%. Winter 2011 4. A gas turbine power plant operates between temperatures 15 ˚C and 1100˚C . Calculate the following: (i) The optimum pressure ratio for the cycle for maximum power output, (ii) Compressor work, Turbine work, Shaft work and Work Ratio, and (iii) Plant efficiency. Take for air, Cp=1.005 kJ/kg-K and k = Cp / Cv = 1.4.
-
Upload
shobit-garg -
Category
Documents
-
view
1 -
download
0
description
Gas turbine problems
Transcript of Gas Turbine Problems
Gas Turbine ProblemsSummer 2013
1. A gas turbine unit has a pressure ratio of 6 and maximum cycle temperature of 610˚C. The isentropic efficiency of the turbine and compressor are 0.82 and 0.8 respectively. Calculate the power output in KW when the air enters the compressor at 15˚C at a rate of 16 kg/s. Take Cp= 1.005 KJ/kg K and γ = 1.4 for compression process and Cp= 1.11 KJ/kg K and γ = 1.333 for expansion process.
Winter 2012
2. Calculate the efficiency and specific work output of a simple gas turbine plant operating on Brayton cycle. The maximum and minimum temperatures are 1000K and 288K respectively. The pressure ratio is 6.The isentropic efficiency of the compressor and turbines are 85% and 90% respectively. If the unit consumes 2 tonnes of oil per hour of calorific value 46500 KJ per kg, determine the power generated .The mechanical efficiency is 905 and generation efficiency is 85%.
May/June 2012
3. In an open gas turbine plant, the pressure ratio through which air at 15 ˚C is compressed is 14. The same air is then heated to a maximum permissible temperature of 1300 ˚C first in a heat exchanger which is 75% efficient, and then in the combustion chamber. The air at 1300 ˚C is expanded in two stages such that the expansion work is the maximum. The air is heated to 1300˚C after the high pressure stage. Determine the cycle thermal efficiency, the work ratio and the net shaft work per kg of air. The isentropic efficiencies may be assumed to be 85% and 86% for compressor and turbine respectively. Calculate the flow rate of air for an output of 240 MW. Assume Mechanical and Generator efficiency 90%.
Winter 2011
4. A gas turbine power plant operates between temperatures 15 ˚C and 1100˚C . Calculate the following: (i) The optimum pressure ratio for the cycle for maximum power output, (ii) Compressor work, Turbine work, Shaft work and Work Ratio, and (iii) Plant efficiency. Take for air, Cp=1.005 kJ/kg-K and k = Cp / Cv = 1.4.
Winter 2010
5. The air enters the compressor of an open cycle constant pressure gas turbine at a pressure of 1 bar and temperature of 20˚C. The pressure of the air after compression is 4 bar. The isentropic efficiency of compressor and turbine are 80 % and 85 % respectively. The air fuel ratio used is 90: 1. If the flow rate of air is 3 kg per secondFind,(i) Power developed(ii) Thermal efficiency of the cycleAssume, Cp = 1 kJ/kgK and γ = 1.4, for air &gas and C.V.of fuel = 41800kJ/kg
