Numerical Simulation And Security Analysis Of Interior Ballistic Of A Cannon With Hybrid Charge

For improving the muzzle kinetic energy of armor pieror, a new generation of large caliber cannon usually adopts high energy propellant and dense mixed charge structure. It challenges for the firing safety, propellant burning will produce significant safety accident under the condition of low temperature especially. Numerical simulation and experimental research is studied for interior ballistic safety engineering design, based on a certain type of tank guns of penetrator mixed charging.According to the artillery fire and charge structure, double one-dimensional two-phase flow interior ballistic mathematical model is established, including center ignition tube and kinds of powder, (granular, rod and tube gunpowder) mixed charging. Combination of propellant ignition and combustion process, ballistic parameters are simulated, the center ignition tube ignition gas pressure, velocity and other parameters of the distribution and change rule are given and the parameters distribution and change characteristics of gas phase and powder particle are analyzed under mixed charging.Based on the combustion mechanism of powder particles, powder burning chemical reaction process are analyzed. Solid powder combustion is simplified for solid phase thermal decomposition and chemical reaction between the propellant gas, the complex chemical reactions of double-base powder are incorporated into the initial decomposition reaction, reduction reaction of NO2, reduction reaction of NO and water-gas reaction. Mathematical model of the quasi steady-state combustion of gunpowder is set up by the chemical fluid dynamics theory.Based on the quasi steady state combustion mathematical model of powder particles, the CFD software Fluent is adopted to simulate simple shape gunpowder combustion process, getting the process of combustion and decomposition of powder particles, the surface pressure distribution of particles is given. According to the distribution of powder particles combustion surface parameters and change law analysis, the surface parameter variation characteristics of particle is given, providing the basis to analyze the stress of the powder particles and the micro combustion mechanism.Test device is designed for studying the powder particle broken. Breakage characteristics of powder particles is studying under low temperature.The crushing mechanism of powder particles are analyzed,pointing out that the powder particles broken inevitability in a certain velocity condition. Combination of powder particle breakage experimental results, by setting different powder particle breakage condition, the interior ballistic process is simulated, according to the result of calculation analysis of the effect on ballistic parameters.Large caliber antitank penetrator interior ballistic process with complicated charge structure is studied through theoretical analysis, numerical simulation and experimental research, the results of the study provide technical basis for ballistic charge security design.