Effect of the evaporator length on start-up performance of sodium-potassium alloy heat pipe

The start-up performance is an important indicator to measure the reliability of heat pipes. The factors, such as the operating angles, evaporator section and condenser section length, affect the start-up characteristic of the thermosiphon. In this study, impacts of the evaporator section and condenser section length on start-up characteristic of a sodium-potassium (Na-K) alloy heat pipe was experimentally investigated. Outside wall temperature distributions of the Na-K alloy heat pipe operating in different length of the evaporator section and condenser section were measured. The results showed that it is beneficial to a uniform temperature distribution to increase the evaporator section length. However, an axial temperature difference was still existed in the region of the liquid pool, placed in the bottom of the evaporator section. © 2016, Science Press. All right reserved.