Experimental and computational study of gas flow delivered by a rectangular microchannels leak

The gas flowrate through a rectangular microchannels device has been investigated within a collaboration between the Istituto Nazionale di Ricerca Metrologica from Torino and the Institut Clément Ader (ICA) from the University of Toulouse. The microdevice was characterized with different gas species as He, N2, Ar, R12, CO2 and a mixture N2/H2 (95/5), in a wide range of pressure, to test its potential use as secondary gas flow standard in terms of ease of use and predictability of gas flowrate. The measurements of gas flowrates have been carried out in an inlet pressure range between 50 Pa and 100 kPa and with two different outlet conditions: vacuum (106 Pa up to a few Pa according to the setup) and atmospheric pressure. Furthermore the temperature coefficient has been determined from measurements in a temperature range from 15 C to 25 C. The primary standards of both laboratories were compared and a semi-analytical model was used to predict the molar gas flowrate through the rectangular microchannels in the slip flow and early transition regimes.