Flow maldistribution in multichanneled microdevices with in-line manifolds

This paper deals with the analyses of fluid flow distribution in a microfluidic device with in-line manifolds. The analysis was performed using commercially available microfluidic simulation software called CoventorWare™. The number of channels in the microfluidic device considered for this study was kept at ten due to limitations on the number of nodes and computational time. Channels with only square profile were analyzed for flow rates varying between 1 to 60 ml/min. The length of the channels was maintained at 1.5 cm for all simulations. The fluid flow distribution characteristics for different channel widths/depths (200, 100, and 75 μm) were investigated. It was observed that the flow rate decreased from the central channels to the outer channels. The flow per channel was symmetric about the geometric centre of the microdevice. The uniformity in flow was accessed using the root mean square value of flow per channel and it decreased with decrease in channel width/depth for a specific flow rate. The difference in the flow rate through the channels increased with increase in total flow rate. Similarly, the spacing between the channels was varied (300, 200, and 100 μm) for a microdevice with channel width/depth of 100 μm and its corresponding flow characteristics were studied for flow rate ranging between 1 ml/min and 60 ml/min. Finally, the length of each manifold was varied between 2500 μm and 1000 μm for understanding the effect of manifold length on flow distribution. The standard deviation of flow per channel did not show much variation with changes in spacing and manifold length. In addition each design of the manifolds was analyzed on the basis of pressure and flow rate as well as velocity profile in each of the channels.