A study to predict the hydrodynamic and thermal characteristics of hybrid mesh regenerator

A Stirling engine is a heat engine that utilizes the cyclic compression and expansion of the working fluid caused by differential temperature for its operation. The regenerator heat exchanger is one of the core components in these Stirling engines, and the performance of the regenerator determines the performance of the Stirling engine. So, in this project, experimental and numerical simulations have been performed to study and compare the thermal and hydrodynamic properties of single mesh and hybrid mesh regenerators. Both single flow and oscillating flow characteristics were studied for single mesh regenerators with wire screens of mesh numbers 300, 400, 500 and hybrid mesh regenerators with wire mesh numbers 300-400-500 and 500-400-300. The oscillating flow study was carried out for 700 RPM, 500 RPM, 300 RPM and 200 RPM. It was observed that the single mesh regenerator with 500 mesh screens has the highest amount of energy storage but at the same time, it was also observed that the 500 mesh has the highest amount of pressure loss gradient. Upon comparing the pressure loss gradient and energy storage it was observed that the hybrid mesh has a better performance as it can store more heat energy with less pressure loss. A correlation was also developed for estimation of the Nusselt number.