Study of Gravity Effect on the Operating Characteristics of High-Temperature Bent Heat Pipes

Abstract As a high-efficiency heat transfer element, heat pipe can be well adapted to the application scenarios of high heat flow density and high safety requirements in the field of nuclear engineering. This paper carries out experiments on a high-temperature sodium heat pipe, and obtains its operating characteristics in the straight pipe state and the bending state respectively. And the operating conditions of the condenser section under different gravity effect was compared. The results show that in the startup process, the temperature difference between the entrance and exit of the bent section increases significantly due to the increase of flow resistance in the bent region. At the same time, even in the bending section of the exit has been started under the conditions of the bending of the temperature difference between the entrance and exit after bending still exists, when the heat pipe into the full start-up state, the temperature difference is gradually reduced to about 10 °C. After bending, the evaporation section to the condenser section of the temperature difference increases, the adiabatic section of the entrance and exit of the obvious temperature difference; and the heat pipe performance of the degree of loss is also related to the bending of the condenser section of the gravity of the orientation.