FILM COOLING OVER A FLAT PLATE WITH COOLANT SUPPLY IN TO TRIANGULAR INDENTATION

Abstract

The modern high-performance gas turbine engines operate at the flow temperatures exceeding the melting temperature of materials, which require the blade cooling. However, the traditional scheme of film cooling is characterized by appearance of secondary vortex structures that destroy the coolant film. From the existing alternative schemes of film cooling, which allow protecting the turbine blades from influence of high temperatures, the scheme with triangular dimples has demonstrated good results in the stationary conditions. This cooling scheme was patented and tested in the Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine. In order to determine the feasibility of such a scheme, it is necessary to consider the effect of the blade rotation influencing the film cooling efficiency. The results are given towards theoretical investigation of the film cooling efficiency of this scheme under rotation conditions. The study was performed using the ANSYS CFX package using SST-turbulence model. The blowing ratio was varied from 0.5 to 2.0. Numerical simulation performed for rotation parameters corresponding to the dominant influence of the Coriolis force – 10, 100 rpm, and centrifugal forces – 3000, 5000 and 7000 rpm. Оn the basis of computer simulation, it has been shown that rotation does not affect weakly the average efficiency of film cooling at Coriolis force, but causes a peak displacement of local adiabatic efficiency, at rotation parameter of 7000 rpm, when there is a distortion of the flow lines.