Thermal behavior of porous plates subjected to air blowing

The cooling of porous plates by air blowing is studied experimentally. The influences of the air injection rate, of the hot main flow temperature, and of the internal heat exchange surfaces of porous media are determined. The experiments show high efficiency for this cooling process, about 97%. Because of the radiative heat transfer occuring within the test section, a large injection rate (about 5%) is required to reach such an efficiency. The critical injection rate is highlighted. Beyond that value the convective heat transfer does not exist any more because the boundary layer is blown off. Our heat transfer model of the porous plate and its vicinity (convective and radiative transfer) emphasizes important temperature gaps between the solid phase and the fluid phase of the porous media. Fitting the model with the experimental data permits an estimate of the internal heat transfer coefficients.