Principle and experimental verification of valve-less pump

In order to meet the demands of transmitting mixed micro-fluidics and micro-fluid media in the fields of biology, chemistry, medicine, aviation, etc., a compositedrag-reducing fluid and avalve-less pump that integrates fluid mixing and pumping was proposed.It enabled simultaneous vortex inducing and mixing by using a bluff body. A new interpretation and expression of flow resistance was established based on fluid flow theory. Aresistance analysis of the vortex-inducing composite bluff body was carried out by a comparative method of pressure around the wake flow and a fluid unit momentum analysis, which revealed the essential mechanisms of the composite bluff body-causing valve and pump. The structure of a traditional valve-less pump was modified, and swirl mixing was realized while the pump-back flow was reduced by introducing a shunt ring and a composite bluff body group. A pump prototype was developed, and the pump flow and fluid mixing tests were carried out at a driving frequency of 11 Hz and avoltage of 180 V. The instantaneous flow rate reached 40.1 ml/min and the fluid was well mixed by the motions of the fluid vortex. These tests verify that the new type of pump can mix and transmit fluidsbetter than other types. It improves the structure and function of the valve-less pump, and at the same time, lays a foundation for the useof valve-less pumps in the field of micro-fluid transmission. © 2019, Science Press. All right reserved.