It is of great importance to understand and predict Residence Time Distribution (RTD) during a singlescrew extrusion process for extruder design and operation optimization purposes. RTD depends on the extruder geometry, operating conditions, and material properties of non-Newtonian fluids. This paper presents the proper dimensionless parameters and RTD for the three-dimensional circulatory flow. These dimensionless parameters were expressed in terms of physical and geometrical parameters such as flow rate, pressure gradient along down channel direction, aspect ratio, helix angle, and power-law index. RTD computations and analysis were based on the finite element method. This dimensionless parameter study is found to be very useful for extruder designers to understand and to predict the RTD systematically.

中文翻译：

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单螺杆挤出过程中三维停留时间分布的无量纲分析

在单螺杆挤出过程中，了解和预测停留时间分布（RTD）对于挤出机设计和操作优化非常重要。RTD取决于挤出机的几何形状，运行条件​​以及非牛顿流体的材料特性。本文为三维循环流提供了合适的无量纲参数和RTD。这些无量纲参数用物理和几何参数表示，例如流速，沿向下通道方向的压力梯度，纵横比，螺旋角和幂律指数。RTD的计算和分析是基于有限元方法的。发现该无因次参数研究对于挤出机设计者系统地理解和预测RTD非常有用。