A Novel Mechanism Study Of A Synthetic Jet Piezoelectric Pump

Piezoelectric pumps can achieve precise control of flow rate by varying the drive voltage and drive frequency applied to the piezoelectric material,and are used in a wide range of precision equipment,such as precision drug delivery systems,active heat dissipation in electronics,etc.Valveless piezoelectric pumps are used in highly integrated precision equipment for their simplicity of construction and ease of miniaturisation.Currently researchers have designed several types of valveless piezoelectric pumps,such as special flow channel types,resistance fluid type,bionic types and synthetic jet types.Special flow channel type and resistance fluid type valveless piezoelectric pumps are prone to fluid pulsation during the suction and discharge cycle and their output flow rate is unstable.The bionic valveless piezoelectric pump can only be used in specific environments,which greatly limits the range of applications.Synthetic jet piezoelectric pumps have been extensively researched by scholars for their advantages of not requiring an additional gas source,having a discharge flow rate greater than the volume of the pump chamber and having a high output flow rate.This paper designed a novel synthetic jet piezoelectric pump based on the synthetic jet principle,contraction tube/expansion management theory and piezoelectric drive theory.The design is based on a tiled type layout and utilises double piezoelectric plates for actuation,which increases the pressure resistance of the pump and increases the volume change rate of the pump chamber.The conical design of the jet pipe is designed to increase the velocity of the jet in the jet chamber and thus allow more fluid to be coiled towards the outlet under strong shear forces.The outlet pipe was designed in the lower part of the pump body to enhance the output pressure and reduce pulsating flow conditions.The jet chamber was ctangular in design and the two inlet tubes were nged on either side of the strong jet to reduce the resistance to fluid suction.The initial parameters were selected to analyse the flow field inside the jet chamber of a novel synthetic jet piezoelectric pump.The main investigations were effect of frequency and amplitude on the flow field and the internal mechanism of the flow state inside the jet chamber.The simulation results showed that the flow velocity and the intensity of the vortex at the exit of the jet pipe increase with increasing amplitude,and that the direction of the jet gradually shifts when the amplitude were greater than 80 μm,resulting in a reduction in the flow at the exit.The flow rate tends to increase and then decrease as the frequency increases,with the flow rate at the outlet gradually decreasing when the drive frequency was greater than 70 Hz.Finally,a prototype has been built and a test system has been constructed.The test results showed that the flow rate of more than 22 ml/min has been achieved at a voltage of 175 V,a drive frequency of 65 Hz,a jet pipe angle(b)of 7°,a jet pipe diameter(a)of 1mm,Stroke length of jet(w)of 10 a mm and a jet chamber depth(L)of 4 mm,which effectively proved the reliability of the simulation analysis.The design and research of the novel synthetic jet piezoelectric pump effectively revealed the intrinsic mechanism of the synthetic jet piezoelectric pump with liquid as the medium and proved that the synthetic jet piezoelectric pump also had good output performance at low frequencies,thus improving the synthetic jet piezoelectric pump for the transport of liquid medium and laying a certain research foundation.