Fluid flow and heat transfer model for high-speed rotating heat pipes

A new complete model has been developed to predict the performance of high-speed rotating heat pipes with centrifugal accelerations up to 10 000 g. The flow and heat transfer in the condenser is modeled using a conventional modified Nusselt film condensation approach. The heat transfer in the evaporator has previously been modeled using a modified Nusselt film evaporation approach. It was found, however, that natural convection in the liquid film becomes more significant at higher accelerations and larger fluid loadings. A simplified evaporation model including the mixed convection is developed and coupled with the film condensation model. The predictions of the model are in reasonable agreement with existing experimental data. The effects of working fluid loading, rotational speed, and pipe geometry on the heat pipe performance are reported here.