Research On The Interior Ballistic Performance Of Variable Burning Rate Sheet Propellant For Mortar

The variable burning rate propellant,as a highly incremental propellant,can effectively solve the problem of matching the energy release of the propellant with the growth rate of the space behind the bomb.At present,the application of this high-increasing charge technology to large-caliber weapons is still in the research stage.In order to realize the application of variable burning rate propellant in mortars,this paper uses theoretical analysis,numerical simulation and experimental research to develop a flake with good combustion incremental properties that matches the internal ballistic performance of the mortar.Propellant.The main research contents and results are as follows:According to the flaky variable burning rate propellant shape structure and combustion physical model,combined with the unique interior ballistic characteristics of the mortar,a suitable interior ballistic model is selected.Mortars have the characteristics of low propellant loading density,low chamber pressure and low initial velocity.Classical internal ballistics theory can better describe the internal ballistic cycle in this situation.Therefore,the classic internal ballistic theory model is chosen to establish Numerical calculation model of interior ballistics adapted to the propellant.And establish the corresponding internal ballistic program of the flake variable burning rate propellant through python language.A program written by python is used to analyze the influence of the charge type parameters on the internal ballistic performance of the sheet-shaped variable burning rate propellant.The simulation results show that:(1)Adjusting the type parameters of the variable burning rate propellant can better improve its internal ballistic performance,meet the internal ballistic performance requirements of this type of mortar,and have a wide range of applicability.(2)In the performance parameters of the propellant,the outer gunpowder power,the inner and outer burning rate ratio,and the thickness of the tablet have a good adjustment effect on its internal ballistic performance,which can effectively reduce the maximum pressure in the chamber and the initial pressure rise rate.According to the preparation process of variable burning rate propellant,the required flake-shaped variable burning rate propellant sample is prepared,and its combustion performance is studied through the closed explosive experiment.This type of mortar was chosen as the experimental platform for internal ballistic experiments,and the internal ballistic performance of the variable burning rate propellant and the fire generated during the launch process were tested and evaluated.The results are as follows:(1)The sheet-shaped variable-burning rate propellant can burn stably at high temperature,low temperature and normal temperature.The arc thickness,length and charge of the sheet-shaped variable-burning rate propellant can meet the requirements of this type of mortar.The results of the interior ballistic test are consistent with the simulation results.(2)Compared with standard propellants,flaky variable burning rate propellants can effectively reduce the flame area produced in the process of launching,and the reduction rate is as high as 98.0%.Through internal ballistic performance theoretical calculation and experimental research,the determined shape and charge parameters of the sheet-shaped variable burning rate propellant meet the internal ballistic indicators of this caliber mortar,and effectively reduce the muzzle flame bad shooting phenomenon.