Research on Liquid Flow Pulsation Reduction in Microchannel of Pneumatic Microfluidic Chip Based on Membrane Microvalve

The unsteady and discontinuous liquid flow in the microchannel affects the efficiency of sample mixing, molecular detection, target acquisition, and biochemical reaction. In this work, an active method of reducing the flow pulsation in the microchannel of a pneumatic microfluidic chip is proposed by using an on-chip membrane microvalve as a valve chamber damping hole or a valve chamber accumulator. The structure, working principle, and multi-physical model of the reducing element of reducing the flow pulsation in a microchannel are presented. When the flow pulsation in the microchannel is sinusoidal, square wave, or pulse, the simulation effect of flow pulsation reduction is given when the membrane valve has different permutations and combinations. The experimental results show that the inlet flow of the reducing element is a square wave pulsation with an amplitude of 0.1 mL/s and a period of 2 s, the outlet flow of the reducing element is assisted by 0.017 and the fluctuation frequency is accompanied by a decrease. The test data and simulation results verify the rationality of the flow reduction element in the membrane valve microchannel, the correctness of the theoretical model, and the practicability of the specific application, which provides a higher precision automatic control technology for the microfluidic chip with high integration and complex reaction function.