HEAT TRANSFER ENHANCEMENT IN OPEN-CELL FOAMS

Fields of applications of foams and the state-of-art, with particular reference to heat exchangers and solar air receivers, are first presented. The characteristics of open-cell foams are then defined and their complex morphology is described. Manufacturing routes of real foams are presented. Physical laws that regulate foaming process and correlations among morphological parameters are presented. Macroscopic and microscopic modeling of foams are reviewed. With reference to the macroscopic approach, governing equations written with the volume averaging technique (VAT) are presented. The microscopic approach allows one to obtain closing coefficients for the macroscopic governing equations. Fluid dynamics and heat transfer mechanisms at the microscopic scale are reviewed. Experimental and numerical investigations on fluid dynamics and heat transfer are presented.