CFD Studies on Pressure Drop for Low Reynolds Fluid Flows Across Orifice in Similarly Shaped Microchannel

Microfluidic devices have great potential in the fields of automation and miniaturization for handling and analysis of fluids. In the present work, study on single-phase flow across orifice in similar shaped microchannel (circular) was carried out under isothermal conditions. CFD Studies were carried out using ANSYS CFX 14.0, varying the fluid velocity (\( U_{m} \)) and orifice contraction ratio (\( \gamma_{do} = d/D \)). Pressure drop characteristics of low Reynolds number Newtonian (water) and non-Newtonian (1.5 % CMC solution, human blood with 45 % haemoglobin and human blood with 70 % haemoglobin) fluids across orifice in circular (\( D \) = 400 µm) were investigated. Simulations were carried out for predicting the orifice pressure drop characteristics for various values of orifice contraction ratio.