Study On Heat Transfer Performance In Three-phase Flow Gravity Heat Pipe

With its high thermal conductivity, heat flux variability, simple structure, high safety and reliability, gravity heat pipe has gradually attracted people's attention and been widely used in waste heat recovery, economizer, the cooling of electronic components, solar energy and spacecraft thermal control and other fields. For heat transfer enhancement of gravity heat pipe, many researches have been carried out, for example, adding ribs on the outside of the heat pipe and adding vertical grooves on the inside of the heat pipe and so on. The three-phase flow heat transfer enhancement technology for gravity heat pipe is presented and investigated in this paper.In this paper,the effects of operation parameters such as filling ratio, heating power and solid holdup on the heat transfer performance of two-phase flow and three-phase flow gravity heat pipes are studied. The research results indicate that the heat transfer coefficient of two-phase gravity heat pipe decreases with the decreasing of the filling ratio and increased with the increase of heat power. For the three-phase flow gravity heat pipe, the effects ofΦ2×3 mm resin,Φ3.15 mm andΦ2 mm polyformaldehyde(POM) on heat transfer are investigated. The results show that heat transfer enhancement effect of resin particle is better than the other two particles. Comparing with two-phase flow gravity heat pipe, the boiling heat transfer coefficient increased by 2.8% to 28.3%, condensation heat transfer coefficient increased by 0.7% to 26.9%. The two POM particles deteriorate heat transfer performance of the heat pipe at heating power less than 2000 W, and enhance heat transfer of the heat pipe at heating power up to 2000 W. The results also show the heat pipe working temperature is lower than the two-phase flow heat pipe with the addition of solid particles,. Therefore, the three-phase flow heat transfer enhancement technology for gravity heat pipe is feasible.