Sintered Nickel Powder Wicks for Flat Vertical Heat Pipes

Energies

Geir Hansen¹  Erling Næss¹  Kolbeinn Kristjansson¹ 

关键词: wick;    sintering;    pore former;    rate-of-rise;    heat pipe;   

DOI  :  10.3390/en8042337

来源: mdpi

【 摘 要 】

The fabrication and performance of wicks for flat heat pipe applications produced by sintering a filamentary nickel powder has been investigated. Tape casting was used as an intermediate step in the wick production process. Thermogravimetric analysis was used to study the burn-off of the organic binder used and to study the oxidation and reduction processes of the nickel. The wicks produced were flat, rectangular and intended for liquid transport in the upwards vertical direction. Rate-of-rise experiments using heptane were used to test the flow characteristics of the wicks. The wick porosities were measured using isopropanol. The heat transfer limitation constituted by the vapour static pressure and the capillary pressure was discussed. The influence on wick performance by using pore former in the manufacturing was studied. When P_cap/P_sat > 1, the use of a pore former to increase the wick permeability will always improve the wick performance. When P_cap/P_sat < 1, it was shown that if the effective pore radius and the permeability increase with an equal percentage the overall influence on the wick capacity is negative. A criterion for a successful pore former introduction is proposed and the concept of a pore former evaluation plot is presented.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.