摘要
为了掌握超临界二氧化碳(SC-CO_(2))塑化双基药在挤出计量段内的流动情况,了解流场内压力、流体速度、剪切速率、剪切黏度等参数的分布与变化情况,使用有限元法的CFD模拟软件Polyflow,对SC‐CO_(2)辅助双基药塑化挤出成型过程中物料在计量段的流动状态进行模拟研究。结果表明,流体压力和剪切黏度都随着工艺温度、注气流率和溶剂比的增大而减小,螺杆转速的提升导致剪切黏度降低,但流体压力却急剧增加。流体外壁面的压力逐级升高,截面处的压力呈现近似环状分布,由机筒内壁面向螺杆表面逐渐减小。截面处的剪切黏度形成以螺杆中心点为圆心的环带状高黏度区域,越贴近机筒内壁和螺杆表面区域的剪切黏度越小,且工艺参数改变不影响剪切黏度的分布规律。流体外壁面的剪切速率随螺杆转速加快而增大,且高剪切速率集中在螺纹处。截面处最大流体速度出现在螺纹附近,紧贴机筒内壁处的流体速度最小,随着远离机筒内壁和螺杆表面流体速度迅速增大,且越靠近螺杆表面及机筒内壁区域的速度梯度越大。
In order to understand the flow state of supercritical carbon dioxide(SC-CO_(2))-assisted double-base propellant within the metering section during extrusion,and to analyze the distribution and variations of parameters such as pressure,fluid veloci-ty,shear rate,and shear viscosity in the flow field,the CFD simulation software Polyflow was employed for simulating the flow state of the material in the metering section during SC-CO_(2)-assisted double-base propellant extrusion.The results show that both fluid pressure and shear viscosity decrease with increasing process temperature,gas injection rate,and solvent ratio.An increase in screw speed leads to a decrease in shear viscosity but a sharp increase in fluid pressure.The pressure on the outer wall of the fluid gradually increases in steps,with pressure at the cross-section exhibiting an approximately annular distribution,decreasing gradually from the inner wall of the barrel towards the screw surface.The shear viscosity at the cross-section forms a ring-shaped high-viscosity zone on the center of the screw.The closer the zone is to the inner wall of the barrel and the screw surface,the smaller the shear viscosity.Furthermore,changes in process parameters do not affect the distribution pattern of shear viscosity.The shear rate on the outer wall of the fluid increases with higher screw speed and concentrates at the thread.The maximum flu-id velocity at the cross-section occurs near the thread,while the fluid velocity close to the inner wall of the barrel is minimal.As one moves away from the inner wall of the barrel and the screw surface,fluid velocity rapidly increases,with a greater gradient observed in zones closer to the screw surface and the inner wall of the barrel.
作者
顾晗
应三九
胡启鹏
张合
GU Han;YING San-jiu;HU Qi-peng;ZHANG He(School of Chemistry and Chemical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《含能材料》
EI
CAS
CSCD
北大核心
2023年第12期1269-1278,共10页
Chinese Journal of Energetic Materials
基金
部委基础创新项目(2019年)。
