NUMERICAL INVESTIGATION OF BLADE PROFILE EFFECTS ON AERODYNAMIC PERFORMANCE OF ULTRA-HIGHLY LOADED TURBINE CASCADES

摘要

The increase of blade loading of a turbine cascade makes it possible to reduce the number of blades and stages, and consequently to decrease both the weights and the costs for manufacturing and maintenance. However, strong secondary flows appear in such highly loaded turbine cascades due to the high turning angles which reduce the efficiency. In the present study, the effects of blade profile on the aerodynamic performance of a stationary linear ultra-highly loaded turbine cascade(UHLTC), which will be used for the future gas turbine engines of hypersonic transport, were investigated numerically. The two and three dimensional calculations were carried out for the flows within the three types of UHLTC, which have the same design turning angle of 160 degree and with the different profile of the suction surface. The first was named 'Original'. The others were 'Up' and 'Down' which had the longer length of suction surface and the shorter one than that of the Original, respectively. In the present computational code, the governing equations for the incompressible turbulent flow which include the standard k-ε turbulence model were solved by the SIMPLE algorithm. The convection term was estimated by the third order upwind difference scheme. The present computed results were examined by comparing with the experimental results. The total pressure loss, the profile loss, the secondary loss and the blade loading distribution for the three types of UHLTC were compared in detail with each other to reveal the effect of blade profile on the aerodynamic performance of UHLTC.