Fluid temperature measurements inside metal foam and comparison to Brinkman-Darcy flow convection analysis

摘要

Actual air temperatures were locally measured inside commercial aluminum foam cylinder heated at the wall by a constant heat flux, and cooled by forced air flow. The specially-developed experimental technique for such measurements is described in detail, and is shown to produce reasonably good data. Air speeds were in the Darcy regime. The permeability of the foam was directly determined from experimental pressure drop points that were obtained using the same experimental set-up. The experimental air temperatures are compared to their analytical counterparts. The volume-averaged analytical formulation employed the Darcy-extended Brinkman model for momentum, and the non-thermal-equilibrium two-energy-equation model for the temperatures of the solid and the fluid phases inside the foam. The solution steps, which are not new, are summarized. A comparison shows good agreement between the experimental and the analytical air temperatures, given the complexity of the foam's morphology and the rounding nature of the volume-averaging technique. However, the analysis seems to under-predict the fluid temperature over most of the cross section. The experimental technique can be used for validation of other analytical solutions, numerical models and heat-exchange engineering designs based on metal foam and similar porous media.