Controlling microchannel gas flow rates through time-modulated pressure pulsation

Abstract

In this paper, the proposition of obtaining controlled time-periodic mass flow rates of gases through axial pressure pulsations in circular microchannels, within the slip flow regime, is critically investigated. Various types of controlling waveforms are studied through the superposition of time-harmonic solutions corresponding to sinusoidal pulsations, as weighted by the pertinent Fourier coefficients and smoothened by appropriate discontinuity-handling functions. These studies effectively explore the extent to which various input parameters concerned with the slip flowboundary condition can influence the mass flow rate controlling mechanism, with variations in the applied pulsation frequency. Based on these considerations, a signature map is also constructed, which identifies the precise flowcontrolling parameters as a single valued function of the operating frequency. This generalized map may not only turn out to be useful for developing a fundamental understanding on the effect of frequency variations on mass flow rate controlled gas microflows but can also provide valuable insights into the design of improved microactuators and micropumps.