Computational analysis of the thermal performance of rarefied air flow in V‐shaped microchannels

In this study, a computational fluid analysis of a slip flow developing thermally and hydrodynamically in a triangular microchannel has been considered. The wall of the channel is preserved at a fixed temperature. Temperature jump and velocity slip boundary conditions are imposed on the surfaces. The microchannel is constructed from seven triangular‐shaped channels and the angle of the microchannel ( θ ) is varied from 0° to 40°. Simulations are carried out for 1 ≤ Re ≤ 8 , 0 ≤ Kn ≤ 0.1 , and the air is used as a working fluid with variable physical properties. The simulation results show that the triangular microchannel can improve heat transfer as compared with plain microchannels. An optimal θ of 20° is found to provide the best heat transfer at moderate frictional losses. Finally, correlations for the average Nusselt number and the average friction coefficient among all parameters are proposed as follows: Nu ̅ = 4.015 Re 0.0255 Kn − 0.1( sin θ )− 0.0479 ,C f ̅ = 3.71 Re − 1.218Kn − 0.296( sin θ )− 0.495 .