Experimental research on the launching system of auxiliary charge with filter cartridge structure

A launching system with a filter cartridge structure was proposed to improve the muzzle velocity of the projectile.The combustion chamber of the launching system is divided into two fixed chambers,one is located in the breech chamber,and the other is arranged in the barrel.The breech chamber charge was ignited first,and the charges in the auxiliary chambers were ignited by the high-temperature,highpressure combustible gas trailing the projectile.In this way,the combustible gas in the auxiliary chambers could compensate for the pressure drop caused by the movement of the projectile.The proposed device features the advantage of launching a projectile with high muzzle velocity without exceeding the maximum pressure in the chamber.In order to obtain some internal ballistic characteristics of the launch system,some critical structure,such as the length of the filter cartridge auxiliary charge,the combustion degree of the propellant in the chamber,and the length of the barrel,are discussed.The experimental results show that with the increased auxiliary charge length,a pressure plateau or even a secondary peak pressure can be formed,which is less than the peak pressure.The projectile velocity increased by 23.57%,14.64%,and 7.65%when the diaphragm thickness was 0 mm,1 mm,and2 mm,respectively.The muzzle velocity of the projectile can be increased by 13.42%by increasing the length of the barrel.Under the same charge condition,with the increase of barrel length,the energy utilization rate of propellant increases by 28.64%.

Temperature influences of the recoil characteristics for aluminum honeycomb buffer in the tether-net launcher

Fluctuations in outer space's temperature would affect the spacecraft's regular operation.This paper aims to study the temperature influences of the aluminum honeycomb buffer in the tether-net launcher.Firstly,a buffer structure was designed to attenuate the pyroshock generated by the pyrotechnic device.Secondly,the mechanical properties of aluminum honeycomb at different temperatures were obtained through quasi-static compression experiments.Then,the internal ballistic responses of the launcher were gained by the closed bomb tests and the equivalent classical interior ballistic model.Finally,the recoil performance of the launcher with aluminum honeycomb buffer at different temperatures was studied.It is revealed that the aluminum honeycomb crushing force gradually decreases with the temperature increases.The peak pressure,burning rate coefficient and velocity increase while the peak time decreases with the temperature increase for the interior ballistics.For the launcher recoil responses,the average launch recoil decreases if the aluminum honeycomb doesn't enter the dense stage.The impact acceleration,projectile velocity and displacement increase as the temperature increase.The paper spotlights the temperature's influence on the recoil characteristics of the aluminum honeycomb buffer,which provides a new idea for buffering technology of pyrotechnic devices in a complex space environment.

Modeling and simulation of bullet-barrel interaction process for the damaged gun barrel

In this paper,the influences of bore damage on the bullet-barrel interaction process and the mechanism of how bore damage results in the end of a machine gun barrel’s service life were studied,which had seldom been paid attention to in the past several decades.A novel finite element mesh generation method for the damaged barrel and a new transient coupled thermo-mechanical finite element(FE)model,which were based on the damage data obtained through barrel life tests,were developed to simulate the interior ballistics process of a coupled bullet-barrel system.Additionally,user subroutine VUAMP was developed in the FE model in order to take the bullet base pressure brought by propellant gas into account.Good consistency between the simulation results and the experimental results verified the preciseness of the proposed mesh generation method and the FE model.The simulation results show that the increase of bullet’s initial disturbance at the muzzle and the variation of its surface morphology caused by bore damage are primarily responsible for the life end of this 12.7 mm machine gun barrel.

Application of Two-dimensional Viscous CE/SE Method in Calculation of Two-phase Detonation

The method of two-dimensional viscous space-time conservation element and solution element (CE/SE) can be used to calculate the gas-liquid two-phase interior flow field in pulse detonation engine (PDE). In this paper, the evolution of the detonation wave and the distribution of its physical parameters were analyzed. The numerical results show that the change of axial velocity of gas is the same as that of detonation pressure. The larger the liquid droplet radius is, the longer the time to get stable detonation wave is. The calculated results coincide with the experimented results better.

Determination of Pressure Profile During Closed-Vessel Test Through CFD Simulation

Two-phase flow modeling of solid propellants has great potential for simulating and predicting the ballistic parameters in closed vessel tests as well as in guns. This paper presents a numerical model describing the combustion of a solid propellant in a closed chamber and takes into account what happens in such twophase,unsteady,reactive-flow systems. The governing equations are derived in the form of coupled,non-linear axisymmetric partial differential equations. The governing equations with customized parameters are implemented into Ansys Fluent 14. 5. The presented solutions predict the pressure profile inside the closed chamber. The results show that the present code adequately predicts the pressure-time history. The numerical results are in agreement with the experimental results. Some discussions are given regarding the effect of the grain shape and the sensitivity of these predictions to the initial pressure of the solid propellant bed. The study demonstrates the capability of using the present model implemented into Fluent,to simulate the combustion of solid propellants in a closed vessel and,eventually,the interior ballistic process in guns.

基于组件的弹射内弹道建模技术

根据弹射器的结构特点以及经典零维内弹道假设,建立了内弹道仿真的数学模型,同时按弹射器的功能特性人为将全系统割分多个标准组件模块,并分别对各组件模块的物理特性构建了独立的分析仿真模型;最后在Matlab/Simu Link平台上搭建了基于标准组件的弹射系统集成仿真模型,并对某系统进行了仿真计算,计算结果与试验结果基本相符。

A Study on Criteria for Barrel Lifetime

Several criteria for barrel lifetime were summarized and discussed. Based on large amount of test data,the advantages and disadvantages of the criteria were analyzed and the requirements for the easy and practical criterion were put forward. Then,a new criterion based on the radical wear at the start points of the barrel lands was proposed. The close interrelationship between the radical wear and interior ballistic characteristics was illuminated theoretically and experimentally. The research results show the great value of this criterion to solve the problem of barrel lifetime.

Modeling and Experimental Investigation of Propulsion Device of the Following KE Penetrator of Tandem Warheads

A propulsion device of following kinetic energy （KE） penetrator of tandem warheads due to shear ring mode is designed. An interior ballistics model is set up with the hypothesis of instantaneous shearing action. The influence of different factors on the interior ballistic characteristics of propulsion device is discussed. The relations between the initial velocity of the following KE penetrator and chamber pressure with time and travel are obtained. The theoretical model is verified through experimental results and can be used as a reference for tandem warheads design.

Modeling and Simulation of Aerial Dispersion on Piston Dispersal Mechanism

For the aerial dispersing interior ballistic process and submunition exterior ballistic initial conditions of cluster munition with piston maximum travel limit, a novel model is established, and the numerical simulation is performed. The piston maximum travel limit and the effect of reaction force on carrier body are researched using the internal ballistic model. Guide tube, cluster munition rotating and submunition assembly are analyzed using the submunition initial external ballistic model. The computational results are consistent with the practical process and the experimental data, and prove the rationality of this model. The theoretical methods are presented for the construction design and dispersion analysis of piston dispersal mechanism.

可燃药筒装药膛内现象的分析

本文对两种不同工艺的可燃药筒燃气生成规律、可燃药筒装药膛内的燃烧规律及压力波的产生进行了分析与比较.所得结论可供带可燃药筒的装药设计参考.