Permeability of a Screen Wick

Abstract

The permeability of a screen wick is a significant factor that governs the performance of heat pipe. The modified Blake-Kozeney equation indicates that the permeability of the screen wick is subject to the porosity of the screen wick. However, the porosity of the screen wick is usually unknown because of the structural complexity of the screen wick especially in the operating condition. Several conceivable parameters such as inter-wire clearance, inter-layer clearance, number of layers, etc. affect the porosity of the screen wick. Nevertheless, Marcus equation does not include these parameters. To include these significant perameters, the present study employs a geometric model in which the shape of the woven structure of the screen wick is represented by piecewise arcs and clearance exists between layers. Based on this model the equation for the permeability of the screen wick is derived. Numerical calculations are performed and experimental measurements are conducted for validation.