In order to reduce backflow and improve output performance, a valveless piezoelectric pump with a reverse diversion channel was produced. The channel was designed based on the structure of the Tesla valve, which has no moving parts and can produce a high-pressure drop during reverse flow. Therefore, this special flowing channel can reduce the backflow of a valveless piezoelectric pump, which has the characteristic of one-way conduction. This work first revealed the relationship between the main structural parameters of the Tesla valve and the kinetic energy difference of liquid. Then, by using simulation software, the structure was verified to have the characteristics of effective suppression of the backflow of valveless piezoelectric pumps. Through setting multiple simulations, some important parameters that include the optimal height between the straight channels (H), the optimal angle (α) between the straight channel and the inclined channel, as well as the optimal radius (R) of the channel were confirmed. Finally, a series of prototypes were fabricated to test the output performance of this valveless piezoelectric pump. Comparing the experimental results, the optimal parameters of the Tesla valve were determined. The results suggest that when the parameters of the Tesla valve were H = 8 mm, α = 30°, and R = 3.4 mm, the output performance of this piezoelectric pump became best, which had a maximum flow rate of 79.26 mL/min with a piezoelectric actuator diameter of 35 mm, an applied voltage of 350 Vp-p, and a frequency of 28 Hz. The effect of this structure in reducing the return flow can be applied to fields such as agricultural irrigation.
Simulation of raindrop-shaped flow tube valveless piezoelectric pump
