Numerical simulation and experimental study on valveless piezoelectric pump with triangular obstacles

A valve less piezoelectric pump with triangular obstacles is designed and manufactured, which uses piezoelectric vibrator as power source. The working principle and theoretical flow rate of the valveless piezoelectric pump are analyzed, and its flow rate expression is derived. The flow resistance characteristics of triangular obstacles are simulated by numerical simulation. Based on the mass fraction distribution of liquid water, the forward and reverse flow resistance of triangular obstacles and the influence of triangular obstacles on pumping capacity are analyzed. Finally, two groups of test prototypes of the valveless pump are made by using the engraving machine, and the flow measurement test is carried out. The experimental results show that the valveless piezoelectric pump with triangular obstacles can realize the valveless pumping function, and the pumping flow per unit time increases with the increase of triangular obstacles in the channel, and decreases with the increase of the distance between triangular obstacles and the channel. When the driving voltage is 140V and the driving frequency is 10Hz, the maximum output flow of the piezoelectric pump is 16.26ml/min.

The characters exploration of a piezoelectric pump with fishtail-shaped bluffbody

This paper focuses on a new structure in the valveless piezoelectric pump, which has a combination structure of the conical flow channel and two fishtail-shaped bluffbodies in the chamber of the pump. The fishtail-shaped bluffbody is inspired by the shape of the swimming fish to diminish the backflow and optimize the performance of the pump. The performance is studied by changing the shape and size of the inlet and outlet, the bluff bodies’ height and the space between two bluff bodies. The results show that the 3 mm × 3 mm square inlet, 3 mm diameter round outlet, 3 mm height of bluffbodies, 6.8 mm pitch of bluffbodies has a best performance in all 10 prototypes, which implements a maximum flow rate of 87.5 ml/min at 170 V 40 Hz with a noise of 42.6 dB. This study makes a preliminary investigation and theoretical explanation for the subsequent optimization of this structure, improved the performance of the valveless piezoelectric pump, broaden the thinking of the design for the bluffbody for better performance of the valveless piezoelectric pump.

Advances in Valveless Piezoelectric Pumps

Piezoelectric pump design is regarded as a hot research topic in the microfluidic field, and has been applied in liquid cooling, precision machinery and other relevant domains. The valveless piezoelectric pump becomes an important branch of the piezoelectric pump, because it successfully avoids the problem of “pump-lagging of valve” during the valve piezoelectric pump processing. This paper summarizes the development of valveless piezoelectric pumps, and introduces some different configurations of valveless piezoelectric pumps. The structure and material of all kinds of valveless piezoelectric pumps are elaborated in detail, and also the output performance of the pump is evaluated and analyzed with the variations in flow rate and output pressure as reference. By comparing the flow of different types of valveless piezoelectric pumps, the application of valveless piezoelectric pumps is also illustrated. The development tendency of the valveless piezoelectric pump is prospected from the perspective of structure design and machining methods, which is expected to provide novel ideas and guidance for future research.

Valveless Piezoelectric Pump with Reverse Diversion Channel

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.

Investigation on the Influence of Design Parameters of Streamline Flow Tubes on Pump Performance

Studies have shown that the valveless piezoelectric pump with streamline flow tubes (VPPSFTs) can increase the flow rate while reducing the vortex, which has a broad application prospect and conforms to the huge potential demand in the fields of medical treatment, sanitation, and health care. The flow runner of the VPPSFT was designed as two segments with a smooth transition between the hyperbola segment and the arc segment. However, the effect of the radius of the arc segment on pump performance is not clear. Therefore, three groups of VPPSFT with arc segments of different curvature radii were designed in this study, and the influence of curvature radius of arc segment on the pump performance was explored. On the basis of the theoretical analysis of fluid continuity and conservation of energy, the structure of VPPSFT was designed, the experimental test was carried out, and the finite element simulation software was used for numerical analysis. The results show that the output performance increases with the increase in the radius of the arc segment, and the maximum flow rate was 116.78 mL/min. The amplitude and the flow rate are almost the same trend as the frequency. This study improves the performance of the valveless piezoelectric pump and provides reference for the structure design of VPPSFT.

Design and Testing of a Valveless Piezoelectric Pump with Conical Vortex Diodes

The valveless piezoelectric pump delivers fluid based on the difference of flow resistance of internal tube. In this paper, a vortex diode with conical tangential tube is proposed, which possesses the great characteristic of reverse cut-off, and the analysis of the forward and reverse flow resistance of the conical vortex diode is verified by finite element analysis. Then, a valveless piezoelectric pump with conical vortex diodes as the internal channel is designed, and the prototype is manufactured. The results of the output performance experiment show that the maximum output flow rate of the valveless piezoelectric pump is 10.44 g/min at the drive frequency of 45Hz, and the maximum output pressure is 560 Pa at the drive frequency of 35Hz. The proposal of the valveless piezoelectric pump provides a good reference for more new types of valveless piezoelectric pumps.