Heat and mass transfer characteristics of transpiration cooling

Correlation equations are found which relate friction factor with Reynolds number and Nusselt number with Reynolds number (or Peclet number) for isothermal and nonisothermal flow through porous materials. The flow and heat transfer characteristics of the scaled-up models and the sintered porous materials were investigated in the laboratory under the countercurrent heat and mass transfer boundary conditions simulating the transpiration cooling phenomenon. It is found that for transpiration cooling purpose, Darcian flow through sintered material suffices to achieve required cooling. Furthermore, it is recognized that the effective thermal conductivity as well as the internal heat transfer coefficient of the porous medium play an important role in determining the wall temperature and the wall thickness.