Propellant Extrusion Molding Simulation And Mold Design

Propellant is a source of energy for the launch of the artillery,and multi-perforated gun propellant is beneficial to improve the dynamic performance of the artillery.Extrusion molding is the main method for the production of propellant.The molding process and the mould directly influence the quality of the propellant.This thesis adopted the computer stimulation as its main method,and the single factor method and orthogonal test method were used to simulate the extrusion process.In order to improve the production process and the performance of the mould,the influence of the main parameters on the extrusion process was studied,and the mould was optimized.Firstly,the three-dimensional model of the propellant extrusion mould was established,and the simulation analysis was carried out.Based on the Fluid-solid Coupling Theory,the Workbench of the fluid-structure coupling module was used as the main tool to simulate the extrusion process.The influences of the parameters,such as compression ratio,shrinkage angle and length of the forming section on the flow of propellant and the deformation of the pin were discussed respectively.The laws of fluid flow and the deformation of the pin were summarized.And the range of the optimum structure parameters of the mould under the condition of single-factor was finally determined.Secondly,the method of orthogonal test was used to optimize the structure size of the extrusion mould.The maximum deformation of the pin,flow channel pressure drop and the outlet flow balance function of the three parameters were selected as the evaluating indexes of orthogonal test.By combining the evaluation standard with the actual production process,this thesis comparatively analyzed and selected the appropriate mould:compression ratio of 3.1,the contraction angle of 55 degrees and the shape of the length of 35mm.Finally,the new kind of mould and the old one were separately used to carry out the extrusion experiment.The Image-Pro_Plus₆.0 software was used to analyze the geometric shape of propellant.To study the distribution of the hole,the combustion experiments of the new mould processing and the old one were carried out in a closed vessel.The results show that the propellant made by the new mould was obviously higher than the original mould in terms of the uniformity of the distribution of the hole,compactness and the gradual burning.