Numerical study on the effect of the number of stages on the performance of Tesla microvalve and comparison with nozzle/diffuser microvalve

In this study، the effect of number of stages on Tesla microvalve performance has been studied. To do this، different layouts including one to four-stage microvalves are investigated numerically. The main criterion is used for evaluation of valves performance is diodicity. Two-dimensional and steady state computations of the fluid flow have been utilized that reveal a strong dependence of diodicity on Reynolds number and the pressure drop. The results showed that for the same flow condition، the diodicity average of the two-stage microvalve is approximately 1. 32 times of that of one-stage. Additional stages increase the complexity and they do not change the diodicity considerably. It is concluded that two-stage layout of Tesla type valve is the best option between the studied layouts. A two-stage layout of this valve in valveless micropump besides being compact، has the adaptability of the various functions. Also، the two-stage valve performance in three different sizes is compared with nozzle - diffuser type valve. Comparisons which are performed based on calculation of diodicity for applicable range of Reynolds numbers show that the diodicity is function of Reynolds number and is independent of the valve size. Also، the superiority of the Tesla type valve for higher Reynolds number and its weakness at lower Reynolds number are shown.