Computational and Experimental Investigation of the Intensity and Scale of Flow Turbulence Influence on Losses in a Vane Cascade

Abstract

Despite the development of experimental and numerical methods for studying the effect of turbulence on the flow structure and gas-dynamic efficiency of turbine cascades, many questions arise when designing and improving the blade rows of high-temperature gas turbines. It is quite difficult to conduct reliable flow measurements or numerical studies for real-life turbomachinery operating conditions, where the range of changes in the intensity and scale of turbulence in the flow is difficult to predict. Therefore, to get closer to understanding how to more adequately take into account the influence of such parameters as the intensity and scale of turbulence when designing turbine rows, a computational study of the gas turbine vane cascade was carried out, which was based on a number of experimental results obtained at the Central Institute of Aviation Motors. To assess the influence of the noted turbulence characteristics on the structure of the flow in the cascade, parametric studies were performed with different intensity values and scales of turbulence specified. In this work, based on experimental data obtained both with and without the use of various turbulators, the influence of the intensity and scale of turbulence on changes in the flow structure and profile losses in the vane cascade is analyzed in the range of values of the reduced (adiabatic) velocity at the exit from the cascade λ_2ad = 0.55–0.95. Computational studies were carried out using the 2D NS software package for the intensity of turbulence at the inlet to the vane cascade Tu = 0.2–10% and at different scales of turbulence.