The effect of the particle size distribution and packing structure on the permeability of sintered porous wicks

In this study, the effects of the particle size distribution and packing structure on the permeability of sintered porous wicks are investigated experimentally and analytically. The wicks with various particle size distributions are prepared by sieving the raw particles into various fractions and the permeabilities of the sintered wicks are measured using an experimental setup which minimizes the wall effect. The size distribution of the particles that constitute each wick is quantitatively measured and the distribution parameters are extracted from the result. Based on the estimated particle size distribution, an analytic model for predicting the permeability of sintered porous wicks is developed. Both experimental and analytical results suggest that the permeability of the sintered porous wicks quasi-linearly decreases as the range of the particle size distribution increases. The Blake-Kozeny's equation which implicitly neglects the effect of the particle size distribution is shown to overestimate the permeability by 40% when the nondimensional distribution range is 0.4. The present model is valid over the range of parameters typically found in heat transfer applications (90 μm < DSM < 350 μm, 0.1 < ΔD/DSM < 0.4). The effect of packing structure of sintered particles on the permeability is shown to be negligible.