The piezoelectric valve-less pump: Series and parallel connections

The piezoelectric valve-less pump is an attractive device to be used as a micropump for low flow rates. In these pumps, the nozzle/diffuser elements that have a preferential flow direction replace conventional valves, to direct the flow from the inlet to the outlet. This work is a study on the performance of such pumps when several of them (up to four) are combined for use in series and/or parallel arrangement. Two basic pumping configurations are considered: (a) pumping of fluid from low pressure to a higher pressure in an open circuit and (b) pumping of fluid in a closed circuit through a flow resistance. The performance analysis procedure developed is simple and quick and allows studying a wide range of operational conditions. Such an analysis is difficult to conduct using elaborate computational fluid dynamics (CFD) approach. The performance characteristics of the different combinations is reported and critically evaluated.