High performance microfludic rectifier utilizing self-induced virtual valves in a sudden expansion channel with a block structure

This study proposed a high performance microfluidic rectifier utilizing self-induced virtual valves in a sudden expansion channel. An embedded block structure is used to enhance the formation of vortices at the sudden expansion channel. The effective hydraulic diameter of the microchannel is reduced due to the formation of the vortices and it hence increases the flow resistance of the microchannel. Flow rectification can be achieved without using any moving part. The developed flow rectifier is able to work at high pressure conditions which most MEMS devices using moving parts can't sustain. Numerical and experimental investigations are used to evaluate the performance of the microfluidic rectifier. Results show that the embedded block structure greatly enhances the performance of the rectifier. The calculated rectification performance indexes (diodicity, Di) reach as high as 1.5 and 1.76 for experimental and numerical results, respectively. The performance of the developed microfluidic rectifier beats the performance of other valveless rectifiers utilizing Tesla valves, simple nozzle/diffuser structures or cascaded nozzle/diffuser structures.