A simple conjugate analysis and its comparison with experiment for heat transfer problems associated with hot gas flows in a partially transpiration-cooled channel

摘要

A simple analytical procedure has been proposed to predict the wall temperature variations due to transpiration cooling. Since the blowing flow through the porous wall strongly influences the hot gas turbulent flow passing over the porous wall, the temperature fields of hot gas turbulent flow in a passage and coolant flow through a porous wall must be coupled and treated simultaneously. The present analysis enables one to treat a whole transpiration system consisting of a porous wall material for the coolant gas and a flow passage for the hot gas, without resorting to any exhaustive numerical computations. The analytical solution based on the local thermal non-equilibrium model for porous media recently proposed by Zhang et al. for transpiration cooling is matched with a near-wall layer analysis for the hot gas con-vective flow. Then, the matched solutions are eventually coupled with the temperature field downstream of the blowing section, obtained solving the energy equation by the method of separation of variables. The estimated wall temperature variations due to transpiration cooling are found to agree well with the experimental data and full numerical results reported in the literature, substantiating the validity of the present analysis for a broad range of hot gas velocity.