Numerical Simulation Of Combustion Gas Flow Field Inside Perforations Of Stick Propellant With Narrow Channels

In propellant charge technology,stick gun propellants with narrow channels are widely used in order to increase the propellant packing density and to maintain progressive burning,but followed by severe erosive burning.Airflow effect is the main reason for the occurrence of erosive combustion.Therefore,it is important to study the gas flow inside perforations of stick gun propellant with narrow channels.The flow model of combustion gas inside the perforation of stick gun propellant with narrow channels was established using reasonable simplifying assumptions in this paper.The numerical simulation of flow process of combustion gas inside the perforation was carried out by solver in FLUENT software.The influence of the three factors on the gas flow distribution and the erosion combustion of the stick gun propellant was analyzed by using the single factor method,which changed the ratio of the length to diameter of the propellant,the initial temperature and the pressure gap between the perforation and outside the perforation respectively.The results show that the flow velocity of combustion gas in the radial direction decreases gradually and the pressure increases from hole center to hole wall;In the axial direction,the velocity decreases and the pressure increases first,then the shock waves are suddenly formed in a certain position and transmitted along the axial direction with time,and tend to be stable eventually.The results also show that the larger the ratio of the length to diameter of the propellant,the smaller the position of the initial velocity fluctuation of the combustion gas inside the perforation of the propellant,the more likely the erosion combustion occurs;The higher the initial temperature of propellant,the faster the burning rate increases,the more prone to erosion combustion;The larger the pressure gap between the perforation and outside the perforation,the greater the frequency of the pressure wave oscillation,the more likely to cause the erosion burning.