Experimental investigations of laminar, transitional and turbulent Gas flow in microchannels

This paper presents experimental results on flow characteristics of laminar, transitional and turbulent gas flows through microchannels. The experiments were performed for three microchannels etched into silicon wafers, capped with glass with hydraulic diameters of 69.48, 99.36 and 147.76 μm. The stagnation pressure was designated in such a way that the flow is laminar, transitional and turbulent with the outflow at atmosphere condition. The pressure was locally measured at seven locations along the channel length to determine local values of Mach number and friction factor from laminar to turbulent flow. The result shows f ⋅ Re is a function of Mach number and is higher than incompressible value due to the compressibility effect for laminar flow. The Darcy friction factor with flow acceleration loss is higher than the Fanning friction factor for both laminar and turbulent flow. The friction factors were also compared with empirical correlations in the literature and Moody's chart.