Experimental study of impurity elements influence on heat transfer performance of high temperature sodium heat pipe

Abstract

This study investigates the heat transfer performance of capillary-driven high-temperature heat pipes filled with 29 g of sodium and doped with impurity elements. An experimental platform was designed to analyze the heat transfer characteristics of these heat pipes. We explored the effects of doping with five impurity elements—oxygen (O), hydrogen (H), magnesium (Mg), carbon (C), and argon (Ar)—on the thermal performance of the sodium heat pipes. The experimental results indicate that the standard heat pipe exhibits lower average temperature differences across the evaporator, adiabatic, and condenser sections compared to heat pipes doped with impurities. Overall, the standard heat pipe demonstrates superior isothermal performance. Relatively speaking, the ranking of heat transfer performance from high to low is as follows: standard > O > H > Mg > C > Ar. The presence of elemental impurities generally reduces the heat pipe’s service life, as well as its heat transfer and start-up characteristics. Non-condensable gases significantly affect the start-up characteristics of the heat pipe. Additionally, carbon reacts with iron, leading to carburization and reducing the heat pipe’s heat transfer performance. Overall, elemental impurities tend to impair both heat transfer and start-up performance, with the degree of impact varying depending on the type of impurity.