Study of a capillary force driven passive valve for a microfluidic package

A capillary force driven passive valve is designed and studied with different valve dimensions to understand the threshold pressure of the valve. A capillary force driven valve has been formed by creating a smaller cross-section compared to the normal fluidic channel. CFD-ACE+, an advanced CFD & multiphysics software is used to conduct simulation to design and study the threshold pressure of the capillary driven passive valves. Circular channels are fabricated on PDMS (poly-dimethylsiloxane) substrate by casting method. The testing set up is based on a hydrostatic design. The simulation, experimental and theoretical results are compared by keeping the larger channel constant, while varying the smaller channels. Studies on the change in the threshold pressure are done with respect to the geometric ratio of the large channel/small channel, keeping the dimension of the large channel constant.