Fig. 1. Schematic diagram of the sodium heat pipe and its mass migration phenomenon (color online) (a) Structure and operational principles of the sodium heat pipe, (b) Mass migration phenomenon in a sodium heat pipe under low-power conditions

Fig. 2. Schematic representation of the experimental platform and thermocouple arrangement (a) Mass migration test bench for the sodium heat pipe, (b) Arrangement of thermocouples on the pipe shell

Fig. 3. The temperature variation at each measurement point in the sodium heat pipe mass migration experiment (color online)

Fig. 4. Schematic representation of the boundary conditions and mesh structure of the sodium heat pipe

Fig. 5. The temporal variations of axial wall temperature distribution (color online) (a) Case 1, (b) Case 2

Fig. 6. The phase distribution of simulation results (color online) (a) Case 1, (b) Case 2

Fig. 7. Variations of temperature difference with time in the sodium heat pipe during the mass migration experiment (color online)