Design and Development of a Convective Air-Cooled Turbine and Test Facility

Demands for higher jet engine thrust-to-weight ratios to satisfy the needs for high Mach number and vertical take-off aircraft are continually increasing. Since World War II, the three-fold increase in thrust-to-weight ratio can be attributed almost entirely to the development of lightweight construction and the axial-flow compressor, and little credit can be given to the meager 200-F increase in turbine-inlet temperature. Increasing turbine-inlet temperature, beyond present-day material limits of 1600-1700 F, by convective air cooling, will increase the jet-engine thrust-to-weight ratio and will markedly improve the performance of the turboprop and bypass engines. The partial results of a program undertaken by the author’s company to develop a fully cooled, flight-type, turbine and test facility are reported. The design heat-transfer considerations are discussed, the test facility described, and performance results to date are given.