Experimental study on an acetone-charged loop heat pipe with a nickel wick

Abstract

In order to push forward the commercial applications of loop heat pipe (LHP) especially in an environment where people are present, it is of great importance to explore alternative working fluids to substitute the commonly used anhydrous ammonia. In this work, an acetone-charged LHP with a nickel wick is developed and experimentally studied, mainly focusing on its startup and heat transport capability. Based on the experimental results and theoretical analysis, some important conclusions have been drawn, as summarized below: 1) The acetone-charged LHP with 2 mm inner diameter pipeline can successfully realize the startup, and reach a heat transport capability of 60W×0.5m; 2) When the inner diameter of the pipeline is increased from 2 to 4 mm, the LHP can start up with a much smaller heat load, i.e., 5 W, achieving a much lower steady-state operating temperature; 3) When the inner diameter of the pipeline is increased from 2 to 4 mm, the heat transport capability of the acetonecharged LHP can be increased from 60 to 100 W. 4) Adverse elevation affects greatly the heat transport capability of the acetone-charged LHP. With the adverse elevation increasing from 0 to 0.2 m, the heat transport capability is decreased from 100 to 60 W. The physical mechanisms responsible for the experimental results mentioned above have been analyzed and discussed. This work contributes to a better understanding on the operating performance and characteristics of the acetone-charged LHP, providing good design guidance and reference for its future applications.

The Pore Microstructure Evolution and Porous Properties of Large Capillary Pressure Wicks Sintered with Carbonyl Nickel Powder

“…For LHPs, the maximum pore diameter in wicks is vitally important because there is backflow of vapor from the evaporation zone to the compensation chamber through the pore with the largest diameter due to the inverse dependence of capillary pressure on pore diameter [ 9 ]. This kind of wick is usually characterized by a porosity of around 50% and a maximum pore diameter of about 1.0 μm [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Although this kind of wick is widely used and exhibits excellent performance, few studies have focused on the fabrication processes of this kind of wick, and its optimal sintering temperature is still unknown.…”