Analysis Of Fluid-structure Interaction On Ultra-high Velocity Metal Jet Penetrating Target With SPH Method

Reservoir rock strength with the increase of well depth,and complexity increase,perforating operation difficulty increases,the need to use high penetration and the damage of low charge perforation,the current charge means of optimization design of grid method mainly physical experiment and numerical simulation is given priority to,the high cost,long period,large risk,not easy to achieve,the numerical simulation problem such as mesh distortion,grid penetration,Resulting in simulation distortion.In this paper,based on the advantages of SPH meshless particle method to simulate explosion impact problem,an initial uniform particle method which can stably transmit detonation wave is proposed and verified.The calculation accuracy is improved by 1.6%and 2.6% respectively,which can simulate perforation penetration problem with high precision.The SPH method and virtual source point method were combined to efficiently analyze the maximum depth of jet penetration into the target plate,and the simulation time of a single penetration example was shortened to about 20 min on average.The influence of the shell parameters on the penetration performance of shaped charge charges was investigated.Compared with the perforation ejection energy of 1.43 mm casing and no casing,the jet energy increased from50.8k J to 68.7k J,the peak value of jet energy of 5.43 mm casing was 88.4k J,and the energy decreased to 84.6k J when the wall thickness of 6.43 mm was 6.43 mm.Increase the thickness of the shell can enhance the ratio of explosion energy is converted into a jet overall,but the shell thickness can increase the detonation scatter the pieces of energy consumption,leading to the jet energy is reduced,compared with no shell and shell with fixed constraint,jet hit a target time consumption decreased by 2%,hit a target speed increased by 58%,reduce failure material scatter Angle from 75 ° to the 33 °,The maximum penetration depth increased from 11.34 cm to 30.47 cm.Using Python and Open CV self-programming,the damage of jet parameters to the target plate was identified,and the damage ratio was quantified.The damage ratio of the free boundary target is 9.35% lower than that of the fixed boundary target.When the density of the jet increases,the damage ratio of the target plate increases.When the jet density does not penetrate the target plate,the damage ratio is only 10.8% and 15.9%.When the density increases enough to penetrate the target plate,the damage ratio increases to 55.0% and 64.7%.The influence of increasing jet diameter on the damage of target plate is only increased between 1mm and 2mm.When the jet velocity is 2000m/s and 3000m/s,it fails to penetrate the target plate,and the damage ratio of the target plate is 45%-55%.For the other schemes of 4000-8000m/s,the jet forming energy penetrates the target plate,and the damage ratio of the target plate decreases to 0-5%.It can be seen that the density and velocity of the jet are the main factors affecting the damage of the target plate.Under the premise that the jet can penetrate,the damage degree of the target plate increases with the increase of the density and decreases with the increase of the velocity.The research results provide a reference for the optimization design of low damage and high penetration charge,and provide reference for the study of SPH method to simulate the penetration of shaped charge into target.