INSIGHT INTO METAL FOAM DOUBLE TUBE HEAT EXCHANGER: SIGNIFICANCE OF PORE DENSITY, PRESSURE DROP CHARACTERISTICS, AND PERFORMANCE ANALYSIS

This study investigates the integration of metal foam heat exchangers into solar flat plate collectors to enhance their thermal performance, addressing a critical need for efficient solar energy utilization. The primary aim is to comprehensively analyze the thermal and fluid flow behavior within this integrated system using numerical simulations conducted with ANSYS Fluent v2021, with water as the working fluid to emulate real-world conditions. Three types of metal foam materials, nickel, copper, and aluminum, with varying porosities (0.80 to 0.90) and pore densities (10 to 30) are considered, and the simulation results are rigorously validated against experimental data. In experimental trials, a nickel metal foam with a porosity of 0.90 and a pore density of 10 pores per inch (PPI) is inserted into the double tube heat exchanger's annular space, and measurements of temperature and pressure drop are collected both with and without the metal foam. The research employs Reynolds-averaged Navier-Stokes (RANS) equations coupled with the k-epsilon model to simulate fluid flow and heat transfer phenomena, treating the metal foam heat exchanger as a porous medium due to its complex geometry. The study's major conclusion is the identification of an optimal metal foam configuration that significantly enhances thermal performance in solar thermal applications. This conclusion is grounded in a thorough evaluation of performance criteria and parameters. Additionally, the research provides valuable insights for engineering design and optimization, ultimately advancing the development of more efficient and sustainable solar thermal systems, which is of paramount significance in the pursuit of cleaner and more sustainable energy sources.