Numerical Simulations of Misalignment Effects in Microfluidic Interconnects

Abstract

AbstractNumerical simulations were performed to see the effect of geometrical misalignment in pressure driven flows. Geometric misalignment effects on flow characteristics arising in three types of interconnection methods a) end-to-end interconnection, b) channel overlap when chips are stacked on top of each other, and c) the misalignment occurring due to the offset between the external tubing and the reservoir were investigated. For the case of end-to-end interconnection, the effect of misalignment was investigated for 0, 13, 50, 58, and 75% reduction in the available flow area at the location of geometrical misalignment. In the interconnection through channel overlap, various possible misalignment configurations were simulated by maintaining the same amount of misalignment (75% flow area reduction) for all the configurations. The effect of misalignment in a Tube-in-Reservoir interconnection was investigated by positioning the tube at an offset of 164μm from the reservoir center. All the results were evaluated in terms of the equivalent length of a straight pipe. The effect of reynolds number (Re) was also taken into account by performing additional simulations of aforementioned cases at reynolds numbers ranging from 0.075 to 75. The results are interpreted in terms of equivalent length (Le) as a function of Re and misalignment area ratio (A1:A2), where A1 is the original cross-sectional area of the channel and A2 is the available flow area at mismatch location. Equivalent length calculations revealed that the effect of misalignment in tube-in-reservoir interconnection method was the most insignificant when compared to the other two methods of interconnection