Computational evaluation of thermal behavior of a wickless heat pipe under various conditions

Abstract

Different techniques were stated in the published literature for predicting the thermal performance of wickless heat pipe (WHP) but detailed modeling results such as flow visualization, and heat transfer features through the geyser boiling occurrences inside the WHP are limited. Hence, it would be valuable to possess a CFD simulation modeling for the WHP. A two-dimensional CFD model of the WHP in ANSYS-Fluent was developed with an in-house code (user-defined functions) to enhance the simulation of the WHP operation which cannot be visualized by experimental studies. Temperature profiles and thermal resistance along the WHP have been investigated under various operating conditions in terms of filling ratios, inclination angles, and heat added. The predicted CFD results are validated against the available experiments with a good agreement. Thermal resistance along the WHP was reduced by rising the heat added. The results showed that the impact of the filling ratios on the average temperature of the evaporator wall at relatively high heat added is more clear compare with low heat added. The results highlighted that the developed CFD model of the WHP can visualize various forms of the droplet, boiling and condensation regimes, and heat transfer at different operating conditions.