Research On A Double-outlet Valveless Piezoelectric Pump Based On Asymmetric Fluid Guiding Structure

Valveless piezoelectric pumps have high application prospects in fuel feed,biomedical,MEMS and other technical fields due to their simple structure,no mechanism wear,high pumping accuracy,no electromagnetic interference,and so on.This paper proposes a new valveless piezoelectric pump that suppresses the return of the valveless piezoelectric pump by weakening the energy of the returning liquid to achieve higher flow output.Through the analysis of the background and current situation of the valveless piezoelectric pump,it is found that the research focus of the new valveless pump is mostly to improve the flow resistance of the structure,and less to solve the existing backflow problem.From the piezoelectric effect and piezoelectric material,the vibration mode and resonance characteristics of the driving components of the piezoelectric pump are studied,and the theoretical formula of the volume change of the pump cavity caused by the piezoelectric vibrator is derived.It is proposed to suppress the backflow phenomenon of the valveless piezoelectric pump by weakening the energy of the returning liquid.Based on the fluid mechanics and the law of conservation of energy,the feasibility of the design idea is verified.An asymmetric flow guiding and double outlet structure for reducing the energy of the return liquid is proposed,and the principle of positively pumping the fluid and reverse suppressing the backflow of the structure is introduced.The overall structure of the new pump was designed by following the weakening of the overall energy of the returning liquid to suppress the backflow of the valveless piezoelectric pump.The structural parameter distance and tail distance which affect the output performance of the new structure are analyzed and studied,and the relationship between the parameter and the energy of the return liquid is derived by combining the fluid formula.The simulation analyzes and simulates the key components and flow field environment in the new structure,which directly reflects the effectiveness of the design,and combines the theory to speculate the selection range of important parameters of the structure.Several sets of test prototypes were developed,and a test platform was set up to test the output flow of the prototype.The results show that the test sample with different parameters shows a trend of changing with the energy of the return liquid in the outputflow.When the pipe spacing and the trailing distance are 8.2 mm and 2.0 mm respectively,that is,the energy of the returning liquid is weakened to the maximum,the output flow of the prototype pump can reach a maximum of 167.8 mL/min,which is in line with the simulation expectation of this parameter.The output flow levels of valveless piezoelectric pumps of different structural types in the field were counted.It is found that the double-outlet valveless piezoelectric pump based on the asymmetric flow guiding structure proposed in this paper has obvious advantages in the total output and the output of the unit drive area.The new valveless piezoelectric pump designed by the method of weakening the energy of the reflux liquid to suppress the reflux has a high output flow level,and the related research work of theory and simulation can effectively guide the design of the structure.