Numerical Simulation Research On Mixing And Safety Performance Of Energetic Material Conical Twin Screw

Energetic materials are widely used in the warhead loading and power source of aerospace,weaponry and equipment.Most energetic materials are composed of high energy density compounds and various additives.At the same time,a high-viscosity adhesive is added to uniformly bond the various components together.Due to the high viscosity characteristics of energetic materials,great viscous resistance will be produced during extrusion processing,which is not conducive to the uniform mixing of energetic materials.At the same time,energetic materials are sensitive to pressure,temperature and shear,and have high requirements for the safety performance of the extrusion equipment.Therefore,this paper is based on the finite element solution method of Polyflow non-isothermal problem,takes the extrusion section,transition body and the extruder head as the research object,and uses the safety mixing as the research purpose to simulate and analyze the field distribution in the flow channel.The main work of this paper is as follows:(1)According to the rheological properties of energetic materials,the Arrhenius Law model is used to correct the influence of temperature on the rheological properties of energetic materials.Design the screw extrusion section,transition body and extruder head structure,and establish the flow channel model corresponding to the above three parts.According to the characteristics of the runner structure,the mesh quality is optimized,and the meshing clearance of the screw and the clearance between the screw and the barrel are partially meshed to improve the accuracy of the simulation results.At the same time,a conical twin-screw SolidWorks modeling plug-in was designed to improve the efficiency of Polyflow’s pre-processing.(2)Based on the non-isothermal steady-state and transient simulations of Polyflow,the screw extrusion section with different thread width,groove depth,thread lead and radial clearance is simulated.According to the simulation results,the distribution of each field quantity in the flow field is analyzed,the cumulative residence time and the average reflux coefficient of the extrusion section are calculated,and the screw safety mixing evaluation system is established to optimize the structure parameters of the conical twin screw.The comprehensive evaluation results of the screw show that the safety performance of the flow field is high and the mixing effect is good in the W3 spiral edge width type,L34 lead type,H8 groove depth type,and G1 gap type.(3)According to the optimized structure parameters of the screw in the extrusion section,a simulation control group with different process parameters is designed.Based on the simulation results of the flow field under non-isothermal steady state and non-isothermal transient state,the safety evaluation coefficient and mixing coefficient of the flow field under different processes are calculated.Considering the safety performance and mixing effect of the conical twin screw,the process parameters are optimized.The comprehensive evaluation results of the process parameters show that when the process parameters are S2 or S6,the overall performance of safety and mixing is the best.