Performance comparison between planar and pyramidal microdiffuser for valveless micropump

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.The microdiffuser is the most important component of the valveless micropump and its design plays a role in the valveless micropump performance to direct the flow in a proper direction. A planar microdiffuser valveless micropump has been compared with a pyramidal microdiffuser valveless micropump using 3-D CFD simulations. Both planar and pyramidal microdiffuser has a throat hydraulic diameter of 0.6865mm and diffuser half angle of 6.65 degrees. The dynamic mesh was applied under different actuation frequency of the micropump diaphragm (8, 50, 100, 200, 500, 1000, and 2000Hz). The net flow rate and the rectification efficiency were calculated for the two valveless micropumps. The results showed that the pyramidal microdiffuser performance was better than the planar microdiffuser for frequency f ≥ 200Hz as the net flow rate generated by pyramidal microdiffuser was higher than that by planar microdiffuser. The highest net flow rate of 18.3μL/min was achieved by the pyramidal microdiffuser at rectification efficiency of 0.35% and actuation frequency of 2000Hz