Automated design and optimisation of dynamic mixing and shear elements for single-screw extruder

单螺杆挤出机动态混合和剪切元件的自动化设计和优化

基本信息

批准号：
327074219
负责人：
Professorin Dr.-Ing. Stefanie Elgeti
金额：
--
依托单位：
Institut für Kunststoffverarbeitung (IKV) in Industrie und Handwerk an der RWTH Aachen
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/327074219?language=en
关键词：
Automated design optimisation dynamic mixing

项目摘要

Mixing and shear elements are increasingly used in single-screw extruders due to the demand for ever higher throughputs while maintaining plastics melt homogeneity. The task of mixing and shear elements is to disperse and distribute additives and fillers evenly in the plastics melt and homogenise the melt thermally. To date, the design of mixing elements is based on the experience of the designer. By contrast, a much more detailed insight into the mixing process can be achieved via three-dimensional simulations. However, available approaches for the computation of mixing operations in extruders often have great limitations and are generally used only for exemplary evaluation of individual mixing elements. Difficulties arise on the one hand in the choice of a suitable mixing index. On the other hand, the high effort in the numerical optimisation of mixing elements is an obstacle to the use of flow simulations in the design phase. So far, there is no software for the automated optimisation of mixing elements available.Against this background, it is the goal of this project to develop an optimisation framework that enables the automated simulative design and optimisation of mixing and shear elements in single-screw extruders. With this framework knowledge about the ideal mixing element geometry in dependence of the mixing task will be acquired. For this purpose, the existing in-house flow solver of the applicant CATS will be modified in order to enable the non-isothermal simulation of the mixing processes in the melt zone of the extruder. The modified solver will then be integrated into an optimisation routine. Meanwhile, the IKV will identify suitable boundary conditions for a realistic three-dimensional simulation of complex mixing elements using a comparison of simulation results and experimental reference data. In the next step, the IKV will simulatively compare different mixing indexes and identify those indexes that are particularly well suited for the design of mixing elements. These mixing indexes are combined into a single objective function in the optimisation framework. In addition, the IKV will simulatively analyse and characterise the cause-effect relationships between the mixing element geometry and the resulting flow conditions. This gain in knowledge will be incorporated into the optimisation framework and facilitate the identification of suitable mixing element sections that will be enabled for the optimisation. Following its successful implementation, the optimisation framework will be used by IKV and CATS in order to design and optimise a mixing element sequence, which is suitable for a very wide range of applications. Thedeveloped mixing element sequence will finally be manufactured and used for the practical validation of the optimisation framework.

由于在保持塑料熔体均匀性的同时需要更高的产量，混合和剪切元件越来越多地用于单螺杆挤出机。混合和剪切元件的任务是将添加剂和填料均匀地分散和分布在塑料熔体中，并对熔体进行热均化。迄今为止，混合元素的设计都是基于设计师的经验。相比之下，通过三维模拟可以更详细地了解混合过程。然而，用于计算挤出机中的混合操作的可用方法通常具有很大的局限性，并且通常仅用于单个混合元件的示例性评估。一方面，在选择合适的混合指数时出现困难。另一方面，混合元件数值优化的大量工作是在设计阶段使用流动模拟的障碍。迄今为止，还没有用于自动优化混合元件的软件。在此背景下，本项目的目标是开发一个优化框架，能够对单螺杆挤出机中的混合和剪切元件进行自动模拟设计和优化。通过该框架，将获得关于依赖于混合任务的理想混合元件几何形状的知识。为此，将对申请人 CATS 现有的内部流动求解器进行修改，以便能够对挤出机熔体区的混合过程进行非等温模拟。然后，修改后的求解器将被集成到优化例程中。同时，IKV 将通过比较模拟结果和实验参考数据来确定复杂混合元件的真实三维模拟的合适边界条件。下一步，IKV将模拟比较不同的混合指标，并找出那些特别适合混合元件设计的指标。这些混合指标在优化框架中组合成单个目标函数。此外，IKV 将模拟分析和表征混合元件几何形状与产生的流动条件之间的因果关系。这种知识获取将被纳入优化框架中，并有助于识别适合优化的混合元件部分。成功实施后，IKV 和 CATS 将使用该优化框架来设计和优化适合广泛应用的混合元件序列。开发的混合元件序列最终将被制造并用于优化框架的实际验证。