| The high-temperature and high-pressure high-speed jets will perforate the perforation gun and the casing,in addition,the perforating fluid strongly fluctuate to form pressure pulastion under the action of shock waves.The safety of the perforation casing strength is affected by the pressure pulastion.However,the dynamic response mechanism of the casing under the pressure pulastion and the strength safety of the casing are still to be studied in depth.The parameters of the detonation products of elemental explosives will be determined by the equilibrium constant method.Explosive capacity calculation formula will be pushed down according to the detonation theory and the Michell-Lesson equation.The paper will revise Berthelot's maximum explosion value analysis scheme with the maximum level of explosive heat realization.The paper will calculate the average specific heat capacity of detonation products,and establishe the formula for calculating the explosion temperature of oxygen-containing coefficients.Detonation velocity and detonation pressure will be solved by Kamelet method and maximum discharge energy principle.For the mixed high-energy explosives containing aluminum,taking into account the influence of molar ratio of aluminum to oxygen and charge density,a new analytical method for the explosion heat,detonation velocity and detonation pressure will be constructed based on the volume-weighted method and the Kameret method.The LS-DYNA software will be used to establish three-dimensional finite element models of perforating bullets,perforating guns,and casings.The ALE algorithm will be used to realize large deformation simulation and fluid-solid coupling during jet formation and penetration,and the analysis of jet formation and penetration shots will be performed.Considering the interaction between the perforating bullets,the energy conversion and distribution law of the perforating system,the variation law of the jet velocity,and the variation law of the casing and the perforating gun stress will be analyzed.According to the energy conversion and distribution law of the perforation system,the energy of the percussive bomb shock wave and the detonation product will be determined.Based on the continuity of the shock wave propagation at the phase transition interface and the Tait equation,the formula for calculating the initial shock pressure will be deduced.Considering the complex boundary of the casing and the influence of the explosion distance,this paper will be establishe the expression of the shock wave propagation law and obtain the theoretical analysis method of the direct shock wave.According to the principle of shock wave reflection,an approximate graphical method for solving the parameters of perforation fluid and casing interface and a theoretical analysis method for reflected pressure waves will be established in this paper.Applying the principle of direct wave and reflection wave superposition,a theoretical analysis method for pressure pulsation law will be established.Workbench software will be used to establish a three-dimensional finite element model of the perforation section casing.The transient dynamic response of the casing under the perforation pressure fluctuation will be analyzed to obtain the dynamic stress distribution and change law of the casing in the perforation section.This paper will be analyze the strength and safety of non-perforated casing and perforated casing respectively,and compare the strength and safety of perforated casing under the action of dynamic and static pressure.Through research,this article will establish a new method for the analysis of detonation parameters of single explosives to improve the calculation accuracy,construct a new analysis method for explosive detonation and detonation pressure of mixed high-energy explosives containing aluminum,realize the formation of shaped-energy jets and fluid-solid coupling and dynamic simulation in the process of penetrate perforating guns and casing.Theoretical analysis method of the pulsation law of the shaped perforation will be established and analyze the strength safety of the perforation section casing under the dynamic and static pressure.The related research results can provide reference for the formation of the shaped perforation pressure pulsation and the safety analysis of the perforation section casing strength. |
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