Computational study of simultaneous heat and mass transfer in turbulent separated flow

Many real problems of engineering interest contain regions of highly turbulent flow that exhibit separation and recirculation. An understanding of heat and mass transfer characteristics in these regions is of considerable importance in industrial practice. In this study, a finite volume numerical method is developed and utilized for the prediction and analysis of flow over a cascade of turbine blades involving simultaneous heat and mass transfer. The renormalization group (RNG) approach based nonlinear $k - epsilon$ turbulence model is utilized to describe the flow field. The computational procedure involves the simultaneous solution of the time averaged equations of motion, heat, mass, turbulent kinetic energy and its dissipation in generalized body-fitted coordinates.;The first part of this study is aimed at the development of an algorithm and its validation through the analysis of a number of benchmark test cases. These include the turbulent flow with and without heat transfer downstream of an abrupt channel expansion, turbulent flows in the wake of a flat plate and isolated airfoils, and flow past airfoil cascades with and without trailing edge separation. The results are compared with the available experimental data and shown to be in excellent agreement.;The second part involved parametric study of the transpiration cooling of a turbine blade cascade. Flow past turbine blade cascades with simultaneous heat and mass transfer are analyzed for Reynolds numbers from 5 $times$ 10$sp5$ to 2 $times$ 10$sp6$ and flow angles from $-$30$spcirc$ to 55$spcirc$. The effects of the separation were appreciable in the suction side and the Nusselt and Sherwood numbers in the separation zone reached a maximum at the reattachment point. It is found that the behavior of the separated shear layer plays an important part upon the heat transfer in the recirculation zone. Correlations between the average and the maximum Nusselt numbers and the Reynolds number as well as the average and the maximum Sherwood numbers and the Reynolds number suitable for application to turbine blades are developed.;The last part of this study involved the prediction of stalled flow in axial compressor cascades. The performance of the algorithm is analyzed and the results from the present study are compared with the available experimental and computational results.