Numerical and Experimental Investigation of Transpiration Cooling with Carbon/Carbon Characteristic Outflow Distributions

Abstract

The present paper deals with the investigation of transpiration cooling. A coolant is injected through a porous ceramic matrix composite material into a channel where it is interacting with a subsonic hot gas flow. The main focus is on the experimental and numerical investigation of the influence of nonuniform mass injection on the temperature in the hot gas flow near to the wall. First of all, the permeability and outflow distributions of a carbon/carbon composite sample are determined experimentally. This sample is then used for the transpiration cooling experiments in a wind-tunnel facility. Corresponding numerical simulations are performed using two separate solvers for the hot gas flow and the porous medium flow. These are applied alternately and coupled to each other by boundary conditions imposed at the interface. In addition to previous work, the coupling conditions are modified using experimental outflow measurements to account for local mass injection. The computations are able to reproduce the experimental findings concerning the influence of the porous medium on the formation of the cooling film in the hot gas channel.