Heat Transfer Enhancement in Stirling Engines Using Fins with Different Configurations and Air Flow

Abstract

The Stirling engine, in comparison to other classical engines, is an external enclosed heat engine cycle with extraordinary theoretical efficiency and minimal emissions. However, when combined with a minor heat source, the productivity of the Stirling engine suffers. Thus, this study emphasizes research on improving engine performance using heat transfer. A simulation was done using CFD analysis in ANSYS Fluent to enhance heat transfer using different types of fins, air blowers, and roughness. κ-ω SST model was used as the turbulence model to capture the heat transfer behavior near and away from the surface. All runs showed a higher heat transfer rate per unit area than the no finned case. Increasing the number of fins reduces the heat transfer by 10 %, Applying this solution would cost more since more material is needed to decrease the gap between fins. When doubling the length of the fin, the heat transfer of the circular design was reduced by 1%, the pinned design by 5%, and the squared design by 30%. The addition of fins reduced the flow of heat to the cold end and kept the temperature near the cold end below 100°C. Increasing the roughness resulted in a small increase in heat flow. Comparing the laminar flow to the transitional flow, the transitional flow increases the heat transfer by 1000%. Keywords: Stirling engine, Fin efficiency, Turbulent flow, Convection, Heat transfer