UNSTEADY GASEOUS FLOWS IN RECTANGULAR MICROCHANNELS - FREQUENCY-RESPONSE OF ONE OR 2 PNEUMATIC LINES CONNECTED IN SERIES

This paper represents an initial analysis of unsteady gaseous Bows in a rectangular microchannel under usual pressure and temperature condit ions. The effect of depth and aspect ratios of the cross-section is in vestigated. With most fluid-based mechanical microsystems of snail int ernal dimensions and subject to normal pressure and temperature condit ions, flow is rarefied with slip at the walls. This flow is then model ed by the Navier-Stokes equations combined with slip and temperature j ump conditions at the walls. These conditions are represented by Maxwe ll-Smoluchowski first order equations. By concentrating essentially on the pulsed sinusoidal regime, it is shown that the instantaneous flow rate amplitude, as well as the band pass of the microchannel are unde restimated when slip at the walls is not taken into account. The frequ ency response of two microchannels connected in series with different cross-sectional areas is also studied. Finally, the proposed model can serve as a tool giving information about the current feasibilities of pressure sensors for the measurement of the dynamic characteristics o f gaseous flows in microchannels. (C) Elsevier, Paris.