EXPERIMENTAL INVESTIGATION OF CONVECTIVE BOILING HEAT TRANSFER FOR R-134A FLOW IN METAL FOAM FILLED VERTICAL TUBE

The present work reports an experimental investigation for the convective boiling heat transfer of R-134a in vertical tube filled with metal foam. High porosity (0.95-0.98) with PPI (40-80) metal foams (open-cell) are being considered to improve heat transfer process. Both of hydrodynamic and heat thermal performance are investigated. The results indicate that the metal foams significantly increases both heat transfer coefficient and Nusselt number but at the expense of increasing the pressure drop with mass flux rang 3-40 kg/m2.s. New correlations are proposed to predict the pressure drop and Nusselt number and show good agreements with previous experimental and numerical works.