Investigation of the effect of air film blade cooling on thermoeconomics of gas turbine based power plant cycle

Abstract

In present paper analysis of the effect of operating parameters on thermoeconomics of the basic-gas-turbine with internal convection air film blade cooling has been reported. Thermoeconomics includes exergy, economics, and exergy costing analysis based on average cost theory. Exergy is chosen as the basis of cost assignment (exergy costing). The analysis of result indicates that the exergetic efficiency falls and incremental rise in power output also decreases with an increase in the amount of bled air (for cooling of blades) from the air compressor. The blade air coolant requirement depends on the allowable temperature of blade material and turbine inlet temperature. Generally, the thermoeconomic analysis is done to minimize the total cost of such energy systems. The calculations have been made for different pressure ratio and TIT so that effect of this decision variable on the cost of the plant can be analysed. The cycle has been analysed for various cases. Results of one of the case for cycle parameters (rpc = 20, TIT = 1500 K, ηAC = 88% and ηGT = 90% with mass flow rate of air 500 kg/s) being, investment cost flow rate (Z˙), cost rate of fuel (C˙f), total cost flow rate (C˙T) and exergetic efficiency (ε) being 0.6334$/s, 1.8891$/s, 2.5225$/s and 60.52% respectively.