Numerical Simulations and Experimental Comparison on Thermal and Fluid Flow Characteristics of Metal Foam Double Tube Heat Exchanger

The paper presents a numerical investigation using ANSYS Fluent v2021 to study a metal foam heat exchanger integrated into the absorber plate of a double tube heat exchanger for a solar flat plate collector. The goal is to analyze the system’s thermal and fluid flow behavior. Water is employed as the working fluid in the simulations. Three types of metal foam (Nickel, Copper, and Aluminum) with porosities ranging from 0.80 to 0.90 and pore densities of 10 to 30 are considered. The simulations are validated against experimental data obtained under similar operating conditions. In the experiments, a nickel metal foam with a porosity of 0.90 and a pore density of 10 PPI is inserted into the double tube heat exchanger's annular space. Temperature and pressure drop measurements are taken with and without the metal foam. The numerical simulations adopt the Reynolds-Averaged Navier-Stokes (RANS) equations with the k-epsilon turbulence model to simulate fluid flow and heat transfer. The metal foam heat exchanger is modeled as a porous medium. The investigation aims to identify the optimal metal foam configuration for enhanced thermal performance in solar thermal applications, providing insights for engineering design and optimization. The performance evaluation criteria enable a comprehensive understanding of the effectiveness and applicability of the metal foam heat exchanger for solar thermal applications, providing valuable insights for engineering design and optimization.