Low-pressure gas flow properties of sintered stainless steel microporous media

The gas flows through the low permeable porous media are of great interest, especially in vacuum technology for filtering, separation processes, protection, and flow control. They can combine a high mass rate level rarefaction. transient experimental technique, developed previously measurements microchannels [Rojas Cardenas et al., Phys. Fluids 23, 031702 (2011)], is generalized to obtain permeability conductance directly from pressure variation measurements. present methodology, allowing step by data verification, leads higher accuracy than similar commonly used method such as “pulse-decay” techniques [W. F. Brace R. J. Martin, Int. Rock Mech. Min. Sci. 5, 415–426 (1968)]. measured fitted according exponential function with relaxation time single fitting parameter. sintered stainless steel microporous medium different gases. By using methodology proposed Johansson al. [Int. Heat Mass Transfer 142, 118412 (2019)], characteristic pore size sample was determined be equal 1.5 micrometers. It found that free molecular constant achieved at below 30 mbar helium. This property makes this kind particularly suitable leak element taking advantage constancy regime, example, calibration ionization gauges or spectrometers [Yoshida Measurement 45(10), 2452–2455 (2012)].