Three-dimensional numerical study of flow physics of single-phase laminar flow through diamond (diverging-converging) microchannel

Diamond microchannel is a non-uniform microchannel that has both diverging and converging flow passages of certain lengths. In this work, three-dimensional simulation and analysis of single-phase laminar fluid flow through diamond microchannel has been carried out for different geometrical and flow parameters. Water is taken as the working fluid. The pressure drop exhibits linear dependence on mass flow rate and varies inversely with inlet angle, width ratio, and hydraulic diameter, which is similar to a straight channel. A non-linear behavior is observed for microchannel with higher inlet angle and higher width ratio, which suggests flow transition because of the presence of recirculation and separation zones. The inlet angle and width ratio are identified as the critical parameters that characterize the flow. An appropriate length scale is defined to make the overall pressure drop of diamond microchannel same as an equivalent uniform microchannel. This characteristic length located at 1/7th of the total length of the microchannel from the inlet makes the pressure drop of microchannel independent of its geometric and flow parameters. The local flow behavior has been further analyzed with the help of pressure, velocity and shear stress profiles. These results are significant due to the relevance of diamond shape microchannel in the design of micromixers, microreactors, and micropumps.