Sodium-Potassium Alloy Heat Pipe under Geyser Boiling Experimental Study: Heat Transfer Analysis

Abstract

In the geyser boiling mode, the working fluid state is divided into a boiling process and a quiet process, and the sodium-potassium (Na-K) alloy heat pipe can discontinuously transfer heat at each boiling. The overheating of the liquid working fluid at the bottom causes short-term boiling and forms slug bubble, the strong condensing ability quickly conducts heat from the evaporator section. And geyser boiling can occur before the working fluid forms continuous flow, so it transfers more heat at lower temperatures than natural convection cooling. In this study, the heat transfer process of a Na-K alloy heat pipe with forced convection cooling under different heating power was experimental studied. The geyser boiling mode can make the Na-K alloy heat pipe work below 650 °C and reduce the start-up time. In the process of geyser boiling, the heat transfer quantity was increased by the boiling frequency and the amount of vapor produced in a single boiling. The boiling temperature had no obvious change with the increased of heating power, and the condenser section temperature increased with the heating power.

Experimental investigation of pulsation behaviour and performance of pulsating heat pipe

“…The average temperature variation on the PHP surface (evaporator, adiabatic and condenser sections) in the flow direction at 30% FR and 0.0799 bar pressure is given in Figure 6. The average condenser temperature was increased with an increase in heat input, and similar temperature variation along the heat pipe surface (evaporator, adiabatic and condenser) is observed by Ahmad et al 2 and Zhang et al 24

Figure 6.Average temperature variation of PHP with varying heat input.

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