Effect of Blade Deflection Angles, Pressure Drop, Flow and Work Co-Efficients on Stage Performance of a Gas Turbine Shrouded HP Compressor Blade

In this paper a methodology for stage performance analysis of an axial flow compressor is carried out. A 1D/2D simulation based on Aero-thermodynamics is used to study the on and off-design performance of the HP compressor. Performance curves are obtained by changing the performance parameters in terms of design parameters like blade deflection angles, pressure drop, flow and work co-efficient’s, diffusion factor, solidity and Mach number. Results show the effect of diffusion factor on increasing efficiency than that of solidity and also the effect of both diffusion factor and solidity in increasing the amount of compression and compressor efficiency. Highest efficiency was found at the mean line between the root and tip of the blade. Best compressor efficiency is found at outlet metal angle in the range 51° to 55°. It was found that at hot section, HP compressor blades typically fail because of creep. Creep occurred as components are operated under high stresses and temperature over a time period. As per thumb rule (>15°C), i.e 20°C to 25°C increase in blade temperature if observed cuts creep life by 50%. Creep strain is of prime importance, because it leads to progressive reduction of rotor tip clearances causing axial and radial blade tip rubs, calling for fixity of shrouds at the rotor HP blade tip. Creep behavior in rotor HP blades are analyzed effectively by use of Industrial best practice like Larson Miller Parameter diagram.