Numerical study on the performance of Tesla type microvalve in a valveless micropump in the range of low frequencies

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In this study, the performance of Tesla-type microvalves, used in micropumps for low frequency driving force, is examined. Three-dimensional and unsteady numerical analysis of fluid flow inside a valveless reciprocating micropump in the range of low working frequencies is carried out. Reciprocating movement of flow actuator provides the actuation and pumping of the working fluid. Ferrofluidic valveless micropump is one practical sample of this kind of micropumps that operate in the range of low working frequencies. To model the reciprocating movement of flow actuator, two time varying functions that includes sinusoidal and step excitation are employed. Also, the performance of nozzle-diffuser valve for the same range of frequencies is examined and its performance is compared with the Tesla valve. The simulation results of the ferrofluidic valveless micropump with the nozzle-diffuser valve show good agreement with the experimental data and linear relation between head and flow rate in micropump is confirmed. Performance curve, the flow rate versus head, is obtained for different working frequencies. The simulations show that the micropump with Tesla type valve in comparison to micropump with nozzle–diffuser type valve has lower maximum flow rate for all range of operating frequencies. However, it has higher maximum head at high operating frequencies. These results show the weakness of the Tesla type valve in low working frequencies and Reynolds numbers.