Design And Experimental Research On Bionic Pistol Shrimp Piezoelectric Jet Pump

Based on the movement characteristics of the pistol shrimp pincers and the advantages of piezoelectric stacks and flexible hinges,a new bionic pistol shrimp piezoelectric single nozzle jet pump with the characteristics of simple structure,stable operation and low noise is proposed.Through systematic design,optimization,and experimental research,the fluid injection and advancement of underwater mechanisms have been realized.The main research contents of this paper include the following aspects:First of all,the paper analyzes the traditional piezoelectric pump both at home and abroad and the movement mechanisms of the pistol shrimp pincers.Then,on the basis of the previous study of piezoelectric pump in the research group and the piezoelectric basic knowledge and the related theory of flexible hinge,a single nozzle jet pump with piezoelectric stack as driving source and flexible hinge as rotary center is designed.The related structural design of the single nozzle jet pump is studied according to the shape of the mobile end of pistol shrimp pincers.Using Workbench simulation analysis software to simulate the static simulation of flexible hinge lever amplification mechanism,so as to obtain the movement structure of the pistol shrimp pincers,the results show that: After an electrical signal is applied to the piezoelectric stack,the piezoelectric ceramic works by stretching the piezoelectric stack along its length.Because the output of the piezoelectric stack is displacement,so the force can be calculated according to the displacement.Through the simulation of the flexible hinge amplification mechanism,we found that when the minimum cross-sectional dimension of the flexible hinge is 1.5 mm,namely,1.5 mm,it meets the structural design needs.In addition,it meets the structural design requirements when the flexible hinge position is determined as the distance between the flexible hinge and the fixed bottom end of 10 mm,that is 10 mm.What’s more,as the piezoelectric stack input voltage increases,the output displacement also increases.Besides,after modal analysis of flexible hinge displacement amplification mechanism is carried out,we obtain its second-order mode is suitable as the best drive mode of jet pump.The experimental prototype of the jet pump is designed by analyzing the movement process of the pistol shrimp pincers and simulating its operation process in combination with its structure.Its thrust of the fluid jet is theoretically deduced and the pressure distribution in the pump chamber is analyzed and the dynamic model of the jet pump is established.Fluid-solid coupling simulation analysis of the pump body is carried out by using the fluid-solid coupling module in COMSOL simulation software,and the optimal simulation results are obtained when the thickness of the diaphragm is 1mm,the pump chamber height is 1mm,the pump chamber diameter is 1mm,the input displacement is 1mm and the input frequency is 60 Hz.Moreover,through the simulation analysis,the influence of pump chamber height,pump chamber diameter and other parameters on the outlet velocity of piezoelectric stack pump is obtained.Combining the simulation results,in order to verify the feasibility of the novel single nozzle jet pump by simulating the movement characteristics of the pistol shrimp pincers,a test platform is set up,and an experimental study of the jet pump prototype is conducted.The working performance of the jet pump is reflected by the measuring distance of the paraffin beads in the water.First of all,by testing the piezoelectric stack pump for basic performance,we conclude that the distance traveled by the paraffin beads increases with increasing voltage.When the maximum voltage of the multifunction signal generator is 100 V,the moving distance of bead is the farthest,up to 2mm.At the same time,changing the frequency of the stack pump input signal,and the movement distance of paraffin beads is farthest at the frequency is 60 Hz.Then the pump body structural parameters were optimized by jet pump test to analyze the influence of pump chamber height on the output performance.The experimental results shows that with the pump chamber height increases,the paraffin beads moving distance first increased and then decreased,and the movement distance of the paraffin beads reaches the maximum when the height of the pump chamber is 0.8 mm.When analyzing the diameter of the pump chamber,it can be judged that the moving distance of the paraffin beads gradually increases with the diameter of the pump chamber according to the experimental curve drawn.However,in the experiment of changing the thickness of the diaphragm,it was found that the movement distance of the paraffin beads is inversely proportional to the thickness of the diaphragm,and the pump chamber cannot vibrate when the thickness of the diaphragm is increased to a certain extent.The above experimental study preliminarily verifies the feasibility of using a piezoelectric stack drive and a flexible hinge amplification mechanism to implement a bionic pistol shrimp type single nozzle jet pump.