Capillary performance analysis of copper powder-fiber composite wick for ultra-thin heat pipe

• Published in: Heat and mass transfer 2021-06, Vol.57 (6), p.949-960
• Main Authors: Niu, Junyi, Xie, Ning, Gao, Xuenong, Fang, Yutang, Zhang, Zhengguo
• Format: Article
• Language: English
• Subjects: Copper; Engineering; Engineering Thermodynamics; Fiber composites; Heat and Mass Transfer; Heat pipes; Hydrophilicity; Industrial Chemistry/Chemical Engineering; Original; Particle size; Permeability; Sensitivity analysis; Sintering (powder metallurgy); Thermodynamics; Wicks
• ISSN: 0947-7411; 1432-1181
• DOI: 10.1007/s00231-020-02989-5

Excellent ultra-thin heat pipes (UTHP) require a wick with high capillary force (ΔP c ) and a good permeability performance (K). In this work, a copper powder-fiber composite wick was fabricated by sintering of the copper powder and fiber mixture. Effects of the copper powder particle size, copper powder volume ratio, as well as the super-hydrophilic treatment were investigated, and the results indicate that the copper powder volume ratio is the most significant factor by orthogonal experiments. Moreover, sensitivity analysis shows that super-hydrophilic treatment contributes the lower capillary force and higher permeability, except when copper powder particle size is high to 80 mesh and powder ratio is low to 20%. Interestingly, the overall capillary performance (ΔP c ·K) of the super-hydrophilic treated wicks is significantly improved. Besides, for the super-hydrophilic treated wicks, both the smaller copper powder particle size and volume ratio contribute the higher permeability and better comprehensive performance, even though a worse capillary force.