NUMERICAL INVESTIGATION OF HEAT TRANSFER IN TURBINE CASCADES WITH SEPARATED FLOWS

摘要

Modern design of turbine blades usually requires highly loaded very thin profiles in order to save weight and cost. If local leading edge incidence is kept close to zero, then flow separation might occur on the pressure side. Although, it is known that flow separation, flow reattachment and the associated zones of re-circulation have a major impact on the heat transfer to the wall, the turbomachinery community needs an understanding of the heat transfer mechanisms in separated flows as well as models and correlations to predict it. The aim of the present investigation is a detailed study by means of an in-house CFD code, MU~2S~2T, of the heat transfer mechanisms in separated flows, in particular in separation and reattachment point regions. Furthermore, an attempt is made to identify a limited number of parameters (i.e. Re, M, inlet flow angle, etc.) whose influence on the heat flux would be critical. The identification of these parameters would be the starting point to develop special correlations to estimate the heat transfer in separated flow regions.