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Recent Developments to Improve High-Pressure and Intermediate-Pressure Turbine Efficiency
Published January 01, 1987 by Institution of Mechanical Engineers in United Kingdom
A substantial improvement in high pressure (HP) and intermediate pressure (IP) turbine performance has been achieved. Increasing the temperature of the impulse chamber has unloaded the control stage, resulting in improved control stage efficiency and higher turbine efficiency due to the transfer of work to the more efficient reaction stages. Control stage performance has been increased by using a contoured endwall nozzle with new blade profiles.
Turbine internal efficiency of HP and IP turbines has been significantly improved by using three dimensional flow field analysis to determine the fluid properties, gaging and blade inlet flow angle distributions along the meridional plane. Incidence and secondary flow losses have been reduced by decreasing the inlet flow angle at the tip region of the rotating blade and reducing the flow turning angle at the base. Leakage flow loss has also been minimized by lower reaction at the outer diameter section and improved sealing across the outer diameter shroud. The HP and IP reaction blading performance has been further enhanced by developing aerodynamically improved blading sections.