Effect of Particle Morphology and Surface Wettability on Performance of Porous Wick and Loop Heat Pipe

doi:10.3901/JME.2020.14.173

Abstract

Abstract: Two kinds of loop heat pipe (LHP) porous wick with different structures are sintered by spherical copper powder and the branch copper powder witch particle size is 63.5 μm and 66.0 μm. The wettability of the porous wick is improved by chemical oxidation with H₂O₂. The effects of particle morphology and wettability on the porous wick liquid absorption and LHP heat transfer performance are analyzed. The results show that the working fluid has a fast climbing rate in the porous wick of branch particles. When the porous wick is hydrophilic, the suction time for distilled water climbing to 18.0 cm in the branch porous wick is about 85.0 s less than that of the spherical porous wick, and the total liquid absorption mass is larger, which is 2.0 times larger than that of the spherical porous wick. The surface layer of the porous wick has nano-scale structure oxidized by H₂O₂, which enhances the hydrophilicity of the porous wick and improves the liquid absorption performance. Compared with spherical particle capillary LHP, branch particle capillary LHP operates at a lower temperature. When the heating power is 280 W, the operating temperature decreases by 7.6 ℃.

Key words: porous wick, particle morphology, pumping performance, porosity, wettability, heat transfer

CLC Number:

TK142

GUO Hao, JI Xianbing, XU Jinliang. Effect of Particle Morphology and Surface Wettability on Performance of Porous Wick and Loop Heat Pipe[J]. Journal of Mechanical Engineering, 2020, 56(14): 173-179.

References

[1] JOUHARA H, ALMAHMOUD S, CHAUHAN A, et al. Experimental and theoretical investigation of a flat heat pipe heat exchanger for waste heat recovery in the steel industry[J]. Energy, 2017, 141:1928-1939.
[2] MA H T, DU N, ZHANG Z Y, et al. Assessment of the optimum operation conditions on a heat pipe heat exch-anger for waste heat recovery in steel industry[J]. Rene-wable and Sustainable Energy Reviews, 2017, 79:50-60.
[3] REMELI M F, DATE A, SINGH B, et al. Passive power generation and heat recovery from waste heat[J]. Advanced Materials Research, 2015, 1113:789-794.
[4] ZHOU G H, LI J, LV L C. An ultra-thin miniature loop heat pipe cooler for mobile electronics[J]. Applied Thermal Engineering, 2016, 109:514-523.
[5] 汤勇, 唐恒, 万珍平, 等. 超薄微热管的研究现状及发展趋势[J]. 机械工程学报, 2017, 53(20):131-144. TANG Yong, TANG Heng, WAN Zhenping, et al, Deve-lopment status and perspective trend of ultra-thin micro heat pipe[J]. Journal of Mechanical Engineering, 2017, 53(20):131-144.
[6] BUFFONE C, COULLOUX J, ALONSO B, et al. Capillary pressure in graphene oxide nanoporous mem-branes for enhanced heat transport in loop heat pipes for aeronautics[J]. Experimental Thermal and Fluid Science, 2016, 78:147-152.
[7] TANG Y. An essay on the cohesion of fluids[J]. Philosophical Transactions of the Royal Society of London, 1805, 95:65-87.
[8] ELVA M, RENÉ R. The pool boiling heat transfer enhancement from experiments with binary mixtures and porous heating covers[J]. Experimental Thermal and Fluid Science, 2006, 30(3):185-192.
[9] CHI S W. Heat pipe theory and practice[M]. Delaware:Hemisphere Publishing Corporation, 1976.
[10] LI H, WANG X G, LIU Z S, et al. Experimental investigation on the sintered wick of the anti-gravity loop-shaped heat pipe[J]. Experimental Thermal and Fluid Science, 2015, 68:689-696.
[11] XU J Y, ZHANG L, XU H. Performance of LHPs with a novel design evaporator[J]. International Journal of Heat and Mass Transfer, 2012, 55(23-24):7005-7014.
[12] NORTH M T, SARRAF D B, ROSENFELD J H, et al. High heat flux loop heat pipes[C]//Proceedings of the Sixth European Symposium on Space Environmental Control Systems, January 26-30, Albuquerque. The Netherlands, 1997:371-376.
[13] SEMENIC T, CATTON I. Experimental study of biporous wicks for high heat flux applications[J]. Inter-national Journal of Heat and Mass Transfer, 2009, 52(21-22):5113-5121.
[14] SINGH R, AKBARZADEH A, MOCHIZUKI M. Effect of wick characteristics on the thermal performance of the miniature loop heat pipe[J]. Journal of Heat Transfer, 2009, 131(8):082601.
[15] WANG X L, WEI J J, DENG Y P, et al. Enhancement of loop heat pipe performance with the application of micro/nano hybrid structures[J]. International Journal of Heat and Mass Transfer, 2018, 127:1248-1263.
[16] TANG H, TANG Y, YUAN W, et al. Fabrication and capillary characterization of axially micro-grooved wicks for aluminium flat-plate heat pipes[J]. Applied Thermal Engineering, 2018, 129:907-915.
[17] LI J W, ZOU Y, CHENG L. Experimental study on capillary pumping performance of porous wicks for loop heat pipe[J]. Experimental Thermal and Fluid Science, 2010, 34(8):1403-1408.
[18] CHAMARTHY P, DE BOCK H P J, RUSS B, et al. Novel fluorescent visualization method to characterize transport properties in micro/nano heat pipe wick structures[C]//Proceedings of ASME InterPACK, July 19-23, 2009, San Francisco, California, 2009:419-425.
[19] TANG Y, DENG D X, LU L S, et al. Experimental investigation on capillary force of composite wick structure by IR thermal imaging camera[J]. Experimental Thermal and Fluid Science, 2010, 34(2):190-196.
[20] HUANG G H, YUAN W, TANG Y, et al. Enhanced capillary performance in axially grooved aluminium wicks by alkaline corrosion treatment[J]. Experimental Thermal and Fluid Science, 2017, 82:212-221.
[21] HOLLEY B, FAGHRI A. Permeability and effective pore radius measurements for heat pipe and fuel cellapp-lications[J]. Applied Thermal Engineering, 2006, 26(4):448-462.
[22] THARAYIL T, ASIRVATHAM LG, RAVINDRAN V, et al. Effect of filling ratio on the performance of a novel miniature loop heat pipe having different diameter transport lines[J]. Applied Thermal Engineering, 2016, 106:588-600.
[23] 徐计元, 邹勇. 环路热管毛细结构的研究进展[J]. 中国电机工程学报, 2013, 33(8):65-73. XU Jiyuan, ZOU Yong. Research and development of capillary structure in loop heat pipe[J]. Proceedings of the CSEE, 2013, 33(8):65-73.
[24] JI X B, WANG Y, XU J L, et al. Experimental study of heat transfer and start-up of loop heat pipe with multiscale porous wicks[J]. Applied Thermal Engineering, 2017, 117:782-798.