Permeability measurement and analysis for the porous wick in cryogenic loop heat pipe

The porous wick in a cryogenic loop heat pipe is a porous structure sintered by stainless steel powder which provides impetus for the working fluid circulation. Permeability is an important parameter of the porous wick and affects the pressure drop of the working fluid flowing through the porous wick. This article presents an experimental system for measuring permeability based on Darcy's law. The experiments are performed at room temperature with ethanol as the working fluid, while high-pressure N₂ equipment is used to press on the working fluid and accelerate the fluid flow. A series of data of mass flow under different pressure are obtained in the experiment from which the permeability could be figured out. The article analyzes the relationship between driving pressure and permeability in the laminar flow region and gets a reliable permeability value.