Simulation And Virtual Simulation Of Spherical Powder Preparation

Spherical flat powder was one of the propellant forms of various small arms and artillery.Its preparation process was to flatten spherical powder by using a flattening machine in the process of post-treatment.By studying the flow field characteristics of internal solution method and microfluidic method in spherical powder preparation methods,the spherical powder preparation system based on Unity 3D was developed.The specific work contents were as follows:Firstly,the experiment and numerical simulation of internal solution method were carried out.The Euler-Euler multiphase flow standard model and multiple reference frame model were used to numerically simulate the gas-water-nitrocotton/ethyl acetate solution three-phase flow field,and the influences of the dissolution ratio,rotation speed,surface tension and viscosity on pellet size,flow velocity and turbulent kinetic energy were analyzed.The simulation results showed that the increase of rotational speed was conducive to the formation of strong circulating vortex basin in the nitrocotton/ethyl acetate solution near the blade,which promoted the mixing of the solution with water and reduced the size of pellet formation.At the same time,the solution viscosity,interphase interaction force and pellet size decreased with the increase of the solution-cotton ratio.Grey relational analysis was introduced,and the results showed that the influencing factor of rotational speed was 0.31085,and the influencing factors of cotton dissolution ratio,surface tension and viscosity were all 0.1532.Then,the microfluidic experiment and two-phase flow field numerical simulation were carried out to simulate and analyze the fracture process of nitrocotton/ethyl acetate droplets and the influencing factors.The simulation results showed that the neck fracture of nitrocotton/ethyl acetate solution moved away from the fork with the increase of the ratio of dissolved cotton.The droplet length was proportional to the ratio of dissolved cotton and inversely proportional to the two-phase flow rate(flow rate at the inlet of continuous phase/flow rate at the inlet of dispersed phase).The pressure and flow rate detection lines were established at the fracture site,and it was further found that the droplet fracture was mainly affected by pressure and surface tension,while the shear force had little effect.Grey correlation analysis was carried out on the simulation results.The analysis results showed that the influence factors of cotton dissolution ratio and surface tension were 0.1201,and the influence factors of two-phase flow velocity were0.0941.Finally,a virtual simulation system for spherical drug preparation was established.The basic development route of the system from preliminary preparation,three-dimensional modeling optimization,scene construction,virtual simulation to testing was determined,and the functional framework of the system was established.