Study On Melt Heat Transfer Of Energetic Materials By Conical Twin-screw Plasticizing

Energetic materials are extremely important materials in the aerospace and military fields,and their processing and molding processes have been receiving a lot of attention from researchers.Due to the high thermal sensitivity,shear sensitivity,friction sensitivity,and impact sensitivity of energetic materials,it is very easy to generate hot spots during processing and molding due to high processing temperatures or improper processes,which can lead to thermal spontaneous combustion and spontaneous explosion.For this reason,researchers often try to study the process of energetic materials on the basis of experimental studies of polymers,simulation methods and theoretical studies as well.There is no specific agreed theory to describe the whole process of conical twin-screw processing of energetic materials.In this context,it is of great importance to investigate the melt heat transfer in the plasticization of energetic materials by conical twin-screws.In addition,the structure of the conical twin-screw and the installation gap have a significant influence on the melt heat transfer in the processing of energetic materials.The study of the effect of different process parameters and screw structure on viscous dissipation is important for the safe processing of energetic materials with conical twin screws.The following studies were carried out in this project:(1)Based on the melt heat transfer process of energy-containing materials processed by conical twin-screw plasticization,the mathematical model applicable to the processing of energy-containing materials by conical twin-screw is derived with reference to the melt models of singlescrew and anisotropic parallel twin-screw,taking into full consideration the characteristics of the inclination of the conical twin-screw and the viscosity of energy-containing materials with temperature,etc.,and the mathematical equations are used to study the influence of process parameters and screw structure and other factors on the total energy consumption required for the melt section and the effect of viscous heat dissipation,which provides some reference value for safe and green processing;(2)Using FLUENT software,the melt section of a conical twin-screw is simulated to investigate the melting process of energy-containing materials,the melting time,the melting position in order to calculate the percentage of viscous dissipation to the total enthalpy change;by changing the screw structure of the melt section,the influence of the screw groove depth,the thread guide and the screw groove depth on the melting process is investigated;(3)Based on POLYFLOW numerical simulation,the effect of changing the screw structure and radial clearance of the melt transfer section on the temperature,pressure and viscous dissipation was investigated by selecting the appropriate screw structure and adjusting the appropriate screw clearance.