FLOW IN SLOWLY VARYING MICROCHANNELS OF RECTANGULAR CROSS-SECTION

Laminar fully developed flow in streamwise-periodic microchannels of rectangular cross-section has been studied in this work. Based on the lubrication approximation, an analytical approach is proposed for the frictional flow resistance. Using the analytical model developed for straight channels of arbitrary cross-section, compact models are developed for linear and sinusoidal wall shapes. The models are then examined with two asymptotic two-dimensional flows of: (a) very narrow and (b) very tall channels and compared with the available experimental and numerical data in the literature. An independent numerical study is also performed to evaluate the proposed models for the three-dimensional flow case. Effects of the channel aspect ratio and deviation factor on the pressure drop are also investigated. Results for the three-simensional flow show that the proposed compact models capture the trend of the numerical data with good accuracy.