锥形双螺杆加工含能材料熔融过程数值模拟

Numerical Simulation of Melting Process of Energetic Materials in Conical Twin-Screw Processing

螺杆挤出机是连续加工含能材料的一种重要设备,药料经过挤出机的加热和剪切作用能顺利熔融并进一步塑化。通过网格无关分析得出网格数量大于126万后,GCI(网格收敛指数)小于3%且最大压力变化幅度较小,确定采用网格数为1261205的网格进行模拟。首次使用FLUENT中的Solidification&Melting模型对锥形双螺杆挤出机加工含能材料的熔融过程进行模拟,得到熔融段熔体分数、流动速度和温度等参数;基于质量守恒定律模拟分析锥形双螺杆挤出机中药料熔融过程的压力变化。在此基础上,通过改变螺杆转速、机筒温度和螺杆温度,分析了工艺参数对熔融过程的影响;通过改变螺杆的槽深、导程和法向螺棱宽度,分析螺杆结构对熔融过程的影响。

The screw extruder was an important equipment for continuous processing of energetic materials.Energetic material could be smoothly melted and further plasticized by the heating and shearing of the extruder.The grid-independent analysis showed that when the number of grids was greater than 1.26 million,the GCI(Grid Convergence Index)was less than 3%,at the same time,the maximum pressure change was small.It was determined to use a grid with a grid number of 1261205 for simulation analysis.For the first time,the Solidification&Melting model in FLUENT was used to simulate the melting process of the conical twin-screw extruder in the process of processing energetic materials.Through the simulation,the results of the melt fraction,flow velocity and temperature in the melting section were obtained.The pressure change of energetic materials during the melting process of conical twin-screw was obtained based on the law of conservation of mass.On this basis,the influence of process parameters on the melting process was analyzed by changing the screw speed,the temperature of the barrel and the temperature of the screw.The influence of the screw structure on the melting process was analyzed by changing the screw groove depth,lead and normal flight width.