The advent of the gas-turbine engine, with its absolute dependence on high component efficiencies for reasonable economic operation, and the necessity for new materials which will withstand high stresses at much greater temperatures than encountered on steam turbines, has led engineers to review the design of turbines closely both from an aerodynamic and a mechanical standpoint: there is still a great deal to be learnt. Reeman† has outlined the present mathematical approach to the design of turbines and surveyed very comprehensively the mechanical problems that are involved. This paper is intended to indicate the manner in which the aerodynamic design of a turbine has developed from that of its steam predecessor and, in particular, surveys some recent experimental work relating to turbine performance. The general aims of the experimental work are to explore the gas-flow processes within a turbine stage, to determine the associate aerodynamic efficiencies, and to gain some understanding of the limitations imposed upon the aerodynamic design of a stage by the necessity for the high efficiency which is required for economic operation of a gas-turbine engine. The data that have so far come to light, though incomplete, illustrate the general overall characteristics of high- and low-reaction turbines, and also the effect that high Mach number or low Reynolds number may have on turbine performance. To conclude the paper, a brief description of the technique adopted for adequate full-scale testing of turbines is presented. This covers the essential points of, power absorption, instrumentation, and safety precaution. The effects of errors in measurements are also discussed.
Angular Arrangement Optimization of the Support Racks of Gas Turbine Engine to Reduce the Circumferential Unevenness of Gas Flow