Study of self-rewetting fluid applied to loop heat pipe with PTFE wick

Abstract

It’s the first using self-rewetting fluid with PTFE wick structure applied to Loop Heat Pipe System. PTFE wick structure has low thermal conductivity, low sintering temperature thus low cost and high anti-oxidation production for long term using which can also overcome heat leakage when operating. It effectively improves the performance of traditional metal wick structure. However, with the hydrophobic of PTFE material, we can’t directly use water as working fluid. Therefore, this paper adds butanol in water to form self-rewetting fluid which not only easily goes through PTFE wick structure but spontaneously supplements the heating surface, making system operates successfully.After testing the surface tension and heat-transfer performances of LHP system, it shows that LHP system begins to work by adding 3wt% butanol aqueous solution. It has the maximum heat capacity of 400W, the minimum thermal resistance 0.32°C/W and heat flux 20W/cm2 when increasing to 6wt% butanol aqueous solution. It’s also the first point making LHP system operate successfully. Compared to the water-nickel system, butanol-PTFE system halving the total thermal resistance, heat flux increases over 50%, and the lower operating temperature and pressure, thus it can have higher stability and security.