Experimental and numerical studies on the performance of a polydimethylsiloxane valveless micropump

A low cost, simply structured micropump, which is actuated by piezoelectric discs, was fabricated using polydimethylsiloxane. As a flow-rectifying element, diffusers were used instead of passive check valves. To evaluate the performance of a micropump, the deflection of a diaphragm and the flowrate of a pump were measured experimentally for various applied voltages. The deflection of a glass diaphragm was measured using an atomic force microscope. It increased linearly (up to 0.4 μm) with the voltage (up to 150 V) when square voltage waves were applied across a piezoelectric disc. The flowrate of a micropump increased with the applied voltage and decreased with the backpressure. The maximum flowrate was 32.9 μl/min and the shut off pressure was 173 Pa when 150 V square wave voltages were applied at 300 Hz. The micropump was numerically modelled based on the experimentally measured diaphragm deflection-flowrate relationships, and the flow fields were analysed using a numerical method. The calculated flowrates were compared with the experimental measurements, and the results showed that the performance of a micropump could be predicted accurately using a computational model.