Optimization Design of Grooved Sodium Heat Pipe Based on NSGA Algorithm

Alkali metal sodium heat pipe has broad application prospects in hypersonic aircraft, micro nuclear reactor and utilization of solar energy because of its high operating temperature and great heat transfer performance. In this paper, according to the requirements of a heat pipe cooling space nuclear reactor project, a trapezoidal grooved sodium heat pipe is designed. Based on the genetic algorithm of NSGA-Ⅲ, the effects of different operating temperature, steam chamber diameter and groove number on the heat transfer limit of sodium heat pipe are studied, and the optimal solution of heat transfer capacity of sodium heat pipe under the service condition of heat pipe cooling space nuclear reactor is proposed. The study found that the capillary limit initially increased with temperature, then decreases. Within the working temperature range, both the entrainment limit and the condensation limit were likely to become the heat transfer limit of the designed heat pipe. At an operating temperature of 1256 K, with a vapor chamber diameter of 12.8 mm and 20 grooves, the heat transfer limit of the designed heat pipe was 4.56 kW.The designed trapezoidal grooved sodium heat pipe meets the requirements of Mach number and effective capillary radius.