NUMERICAL STUDY ON THE PERFORMANCE CHARACTERISTICS OF CYLINDRICAL HEAT PIPES WITH DIFFERING WICK TYPE

In the current study, the performance of a high temperature, cylindrical heat pipe under various operating conditions is investigated numerically. To find the appropriate geometrical and working parameters of the heat pipe, a two-dimensional axisymmetric model is developed to describe the vapor and liquid flows and heat transfers in the vapor core, the wick, and the wall regions. Sodium and stainless steel are selected as the working fluid, the wick material, and the container material. The compressibility of the vapor and viscous dissipation are taken into account. In the wick region, the Darcy Brinkman Forchheimer model is applied to simulate the liquid sodium characteristics. The effect of wick type, heat input, and operating temperature are studied on the overall performance of the heat pipe as well as vapor and liquid pressure drops. Screen wick, sintered powder wick and felt wick are selected. The results showed that, for the selected wick types, the sintered powder wick resulted in the largest liquid pressure drop and the felt wick resulted in the lowest thermal resistance. In addition, the influence of operating temperature on thermal resistance diminishes with increasing temperature.