Secondary flow and its influences on the fluid flow and heat transfer in a radial rotating heat pipe

Previous experimental investigations have shown the potential of radial rotating heat pipes (RRHPs) as a heat removal device in various rotating machinery applications. Due to spatial limitations, the experimental investigations are typically limited to recording only the temperature of RRHPs operating under various conditions. However, for design and development purposes, the complicated fluid and heat flows in RRHPs need to be investigated carefully. Computational fluid dynamics (CFD) can help investigate that information in detail. In this study a CFD model has been built to simulate the two-phase flow within an RRHP, using a modified and validated solver based on OpenFOAM. The fluid flow in an RRHP under different rotational speeds and its consequences to heat transfer has been analysed. The results show that the secondary flow induced by the centrifugal and Coriolis force has significant impacts on the flow recirculation, phase distribution, and heat transfer in an RRHP. Moreover, the circumferential non-uniformity due to the secondary flow can be significant even at relatively low rotational speed, which is something worth noting for future studies.