Performance of compressed nickel foam wicks for flat vertical heat pipes

• Wicks for flat vertical heat pipes were produced from compressed nickel foam.
• Wicks of different degrees of compression were produced.
• Effective pore radius and permeability were determined by rate-of-rise using heptane.
• Porosity was determined using isopropanol.
• Wick performance was estimated for potassium as working fluid.

The fabrication and performance of wicks for vertical flat heat pipe applications produced by compression of nickel foams has been investigated. The permeabilities and the effective pore radii for the wicks were estimated from rate-of-rise experiments, using the model fluid heptane. The porosities of the wicks were measured using isopropanol. The results, which are new and of vital importance for optimum use of such wicks, show that the permeabilities and the effective pore radii are in the upper range for heat pipe use. The joining pressure required during the sintering of the wicks was determined, and it was discovered that the nickel foams turned hydrophilic during the sintering.