Performance evaluation of multi-stage open-loop impedance pump

Background: Impedance pump is a simple valveless pumping mechanism, which transports fluid through the mismatch of impedance in the system. Mismatch in impedance occurs when an asymmetrical periodic excitation is exerted on the elastic tube. Periodic asymmetrical excitation will then produce a unidirectional flow. Considering a multi-stage system with a single and constant power source, it is well expected that there would be pumping limitation to which the enhancement can reach. Methods: A multi-stage open-loop impedance pump is developed in the current work. The current work experimentally analyzes and evaluates the pumping performance of a multi-stage open-loop impedance pump, with emphasis on the flow rates induced and pumping limitation. Analyses of flow rates, pressure head and excitation frequencies are performed in its non-dimensional form. Results: Taking a single-stage system as benchmark, enhancement of 35 and 33.3% is shown in the flow rate and pressure head respectively for a two-stage system. Enhancement of 110 and 60% is shown in flow rate and pressure head of a three-stage system in comparison to the single-stage system. For four-stage system, however, only 27 and 46.7% increments are demonstrated in the flow rate and pressure head, respectively. Conclusions: The implementation of multi-stage system with single constant power input is demonstrated to be limited only to the three-stage system where the declined pumping performance is exhibited in a four-stage system.