SC-CO2辅助高固含量发射药代料挤出加工的流变行为

Rheological Behavior of High Solid Content Propellant Substitutes in Extrusion Process Assisted with SC⁃CO2

为了改善高固含量发射药挤出加工时流变性能,采用超临界二氧化碳(SC-CO2)作为增塑剂辅助高固含量发射药代料醋酸纤维素/碳酸钙(CA/CaCO3)挤出加工,通过狭缝流变仪和幂律方程研究了CA/CaCO3和CA/CaCO3/SC-CO2溶液的在线流变行为,使用Polyflow软件模拟了CA/CaCO3/SC-CO2溶液的分散混合性能。结果表明,温度为50℃时,SC-CO2使CA/CaCO3溶液的稠度系数降低了26.00%,非牛顿指数增加了16.67%,降低了CA/CaCO3溶液在挤出过程的粘度和压力;随着加工温度的升高,CA/CaCO3/SC-CO2溶液的粘度降低;在低剪切速率下,CA/CaCO3/SC-CO2溶液的剪切粘度对温度的敏感性较高;根据模拟结果,温度为50℃时,CA/CaCO3/SC-CO2溶液经受最大剪切应力的最大概率密度比CA/CaCO3溶液增加了20.63%,SC-CO2的注入有利于CA/CaCO3溶液分散混合性能的提高。

In order to solve the problem of high viscosity of high solid content propellants,supercritical carbon dioxide(SC‐CO2)has been used as a plasticizer to improve its rheological behavior.The in‐line viscosity of the CA/CaCO3 solution was measured by a slit die rheometer during the extrusion process assisted with SC‐CO2,and the Power law was used to describe the rheological behavior of CA/CaCO3 and CA/CaCO3/SC‐CO2 solutions.Polyflow was utilized to model the dispersive mixing properties of the CA/CaCO3/SC‐CO2 solutions.Results show that with the presence of SC‐CO2,the viscosity and pressure of the CA/CaCO3 solution decreases significantly.And the viscosity coefficient of the CA/CaCO3 solution at 50℃decreases by 26.00%,while its non‐Newtonian index increases by approximately 16.67%.As the extrusion temperature increases,the viscosity of the CA/CaCO3/SC‐CO2 solution decreases,and its shear viscosity is less sensitive to temperature at higher shear rate.According to this simulation results,when the CA/CaCO3/SC‐CO2 solution is subjected to the maximum shear stress,the maximum probability density increases by 20.63%at 50℃,which confirms that SC‐CO2 improves the dispersion mixing properties of the CA/CaCO3 solution.