A fast method for determining the flow conductance of gas microfluidic devices

This paper presents a fast method for determining the conductance of gas microfluidic devices with low flow rates and very small pressure drops starting from 30 Pa, corresponding to Re=0.3. This method is based on discharging a gas-pressurized chamber through the microfluidic device under test. The microfluidic device's conductance can be estimated as a function of inlet pressure and the Reynolds number of the flow by recording the upstream pressure during the discharging process and calculating the time derivative of the gas pressure. The pressurized chamber is considered as an isothermal chamber. Experimental results show that a sufficiently accurate isothermal discharging process up to an upstream-to-downstream pressure ratio of 0.8 can be achieved by immersing the chamber in a thermal bath. The method presented here is very fast, requiring only a few seconds for the acquisition procedure and computerized data processing.