Simulation of Ground Power Unit-3 Stirling Engine With Air as Working Fluid

The immediate need to mitigate climate change presents a chance to move civilization in the direction of a more sustainable future. A Stirling engine has multifuel capabilities such as biomass, solar thermal, and waste heat and hence can contribute significantly to the energy mix of fuel sources. The most common working fluids for Stirling engines are hydrogen, helium, and air, with air being the least expensive and safest. Studies analyzing Stirling engine performance with 3D CFD are limited, and even fewer use air as the working fluid. This research presents a novel 3D CFD analysis of the Ground Power Unit-3 (GPU-3) Stirling engine with air as the working fluid using ansys fluent. The fluid domain was modeled in SolidWorks and one-eighth of the geometry was used for simulation with realizable enhanced wall treatment (EWT) k–ε as an eddy viscosity model. On average, there was a reduction in power output by 50% when air was used as working fluid against helium as working fluid. Engine's power output decreases as the engine's speed increases. The impinging effect contributes to vortex formation and temperature variation within the engine components was nonsinusoidal, this is in line with similar studies performed on GPU-3 Stirling engine.