Performance Comparison Between Transpiration Air Cooled Turbine 3000°F (1649°C) Stator Vanes and Solid Uncooled Vanes

Abstract

Testing was conducted to compare the aerodynamic performance of a turbine vane using transpiration air-cooling capable of operation at 3000°F (1649°C) gas temperature with a vane of identical profile with no cooling provisions to determine the effect of cooling on vane kinetic energy efficiency and loss coefficient. The test configuration was a 10-vane section of full scale first stage turbine stator annulus designed for 1.6 pressure ratio, cooling air flow equal to 6.1 percent of primary flow, 3000°F (1649°C) turbine inlet temperature and primary-to-coolant temperature ratio of 2.7. To enable comparison with other investigations, tests were conducted at three pressure ratios from 1.4 to 1.6, three coolant flows from 75 to 120 percent of design, and three primary-to-coolant temperature ratios from 2.70 to 1.15. Efficiency, loss coefficient and flow capacity test results were in good agreement with predicted values for both the transpiration air cooled and uncooled vanes. The testing demonstrated that it is necessary to conduct test evaluations of transpiration air-cooled components at or near design coolant-to-gas stream temperature ratio in order to achieve correct results.