An Experimental Study On The Mechanism Of Cavitation Jet In Gun Shrimp

With snapper claws as the research object,this paper studies the phenomenon of cavitation jets of snapper claws,tries to develop a bionic device for the process of closing the snapper claws and analyzes the cavitation jet mechanism of snapper and its influencing factors,which can provide reliable test data and technical support for the design of underwater non-explosive high-energy generating devices.This paper analyzes the attack mechanism of the living snapper claw,determines the main parameters of the attack test and designs the test system.The attack process,cavitation bubble process and pressure pulse characteristics of different snapper claws were analyzed.The three-dimensional model of the snapper claws was obtained by CT scanning to analyze the structure of the snapper claws.The surface and section microstructure and element composition of the snapper claws were observed and analyzed by FESEM.The modulus and hardness of the snapper claws surface were tested by nano-indentation apparatus.The key parameters of cavitation jet were extracted by CFD simulation to analyze structure characteristics.In this paper,the cavitation theory is expounded and the process of cavitation is studied by means of CAD model and CFD simulation,and the effects of different scale models,closing angle,closing angular velocity and groove at the exit of the pocket on cavitation performance of snapper claws are analyzed.The claws nozzle is simplified to be a two-dimensional nozzle model.The drainage structure of the nozzle is analyzed,and the influence of cavitation caused by different drainage boundary conditions is explored,so as to analyze the influence of wall size on cavitation.A bionic test device was developed by simulating the closing movement of the snapper claws in vivo,and its performance was tested.This paper discusses the design requirements of bionic testing device for snapper claws,puts forward the design scheme of bionic testing device for snapper claws,and sets up a bionic device for the closure process of snapper claws,high-speed photography module and underwater pressure testing module.The bionic device selects the impact cylinder to provide energy for the closure of the snapper claws,and drives the rapid closure of the snapper claws through impacting acceleration lever by the cylinder,thus reproducing the cavitation process of the snapper claws.Titanium alloy was selected to process the bionic claw by 3D printing,and the experimental base was designed.The rationality of the device was verified by Adams dynamic simulation.According to the CFD simulation results,different types of bionic clips were designed.Models of different pinch-shrinkage ratios and models with or without grooves at the exit of the pinch-chest cavity were obtained.Finally,the test process and data processing method of the imitation marlin snapper test system were introduced,and the device performance tests were performed.Bionic experiments were carried out to study the factors that influence cavitation performance of snapper claws.The cavitation performance produced by different shrinkage models,different closing angles and different closing angular velocities was experimentally studied.The influence of different factors on cavitation jet performance is obtained,which is consistent with the test results in vivo and CFD simulation.The influence of the groove at the exit of the cavity on the closed cavitation performance of the snapper trap is analyzed,which provides a test method for further research on the underwater non-explosive high-energy generator.