Sensitivity of a Micro-scale Pump Flow Rate to Actuation Frequency Change

A three-dimensional computational fluid dynamics simulation for a micro-scale pump has been performed to investigate the sensitivity of the flow rate to frequency change during pump and supply phases. Applying dynamic mesh under different diaphragm actuation frequencies ( 8, 50, 100, 200, and 500 Hz ) and sinusoidal oscillation amplitude of 6.0 µm the results showed that at frequency f ≥ 100 Hz the flow separation has been formed in the diffuser direction for both supply and pump phases. At low frequency f ≤ 50 Hz there is no flow separation in the diffuser or the nozzle direction. The large recirculation zone is created at the dif-fuser bottom wall side. The flow separation was found to be frequency and direction dependent for the micro-diffuser half angle of 5o . The net flow rate increased linearly with the frequency while the net flow per cycle was less sensitive to the change of the frequency.