Pumping Power Performance and Frictional Resistance of Textured Microchannels in Gaseous Slip Flows

Abstract

The investigation of pressure drop characteristics along the microchannels with surface texturing is crucial to arrive at a desired structural size and performance of a microchannel. This study presents the comparison of flow friction and pumping power for two different Reynolds numbers (Re = 1.01 and 50.31) for rarefied gas flows in textured microchannels. The three-dimensional microchannel is computationally modeled with ratios of the height of texture to the height of the microchannel taken as 20, 40, and 60% and texture shapes as rectangular, circular, and triangular. All simulations are conducted in the slip flow regime for the Knudsen number ranging from 1.10 × 10 −3 to 2.07 × 10 −2 and tangential momentum accommodation coefficient (TMAC) ranging from 0.1 to 0.9. The time-and cost-effective Taguchi statistical analysis of the L18 orthogonal array is carried out to find the efficiency of the textured microchannels in terms of Poiseuille number and pumping power per unit mass flow rate. It is found that the height of texture is the most important control factor for efficiency, while the shape is the least important factor for both Reynolds numbers. The second most significant factor for Re = 50.31 is the Knudsen number and that for Re = 1.01 is the TMAC. The present numerical work can be applied for designing micropiping systems and diffusers with lower pumping power, lower frictional resistance, and higher efficiency.