GOALI: Optimum Design of Extrusion Dies using the Estimated Elongational Viscosity of Polymers

这个与工业界学术联络的资助机会（GOALI）项目涉及聚合物加工中的两个重要问题。通过开发一种间接测量高分子材料伸长粘度的新方法，将重点研究如何加强对加工过程的控制。此外，优化聚合物挤出模具通道几何形状的努力将根据延长粘度对模具中聚合物流动的影响进行研究。在本项目中，将通过寻找Sarkar-Gupta伸长粘度模型中四个参数的最优值来确定伸长粘度的应变速率依赖性，从而使有限元模拟预测的压力损失与毛细管或狭缝流变仪的相应实验数据之间的差异最小化。该优化模型将在本项目中开发，预计将提供比使用现有软件包获得的设计更好的模具设计，这些软件包不考虑聚合物的伸长粘度。尽管该建议涉及挤压模具的优化，但该研究的成功完成将为包括拉伸粘度对其他聚合物加工技术的设备设计的影响开辟道路，这些技术涉及拉伸主导的流动，如吹塑和纤维纺丝。本项目开发的软件将用于高级课程，以教育学生在聚合物加工中拉长粘度的重要性。在接下来的三年里，一名研究生将每年花一个月的时间在陶氏化学公司进行各种实验，从而从该项目中获得额外的教育效益。

This Grant Opportunity for Academic Liaison with Industry (GOALI) project deals with two important issues in polymer processing. Research will be focused on enhancing the control of the processing through the development a new methods for indirect measurement of the elongational viscosity of the polymeric material. In addition, efforts to optimize die channel geometry for polymer extrusion will be investigated in terms of the effects of elongational viscosity on the polymer flow in the die. In this project, strain-rate dependence of elongational viscosity will be determined by finding the optimal values of the four parameters in the Sarkar-Gupta elongational viscosity model such that the difference between the pressure loss predicted by a finite element simulation and the corresponding experimental data from a capillary or slit rheometer is minimized.The optimization model, which will be developed in this project, is expected to provide much better die design than the design obtained by using currently available software packages, which do not account for the elongational viscosity of a polymer. Even though this proposal involves optimization of extrusion dies, a successful completion of the proposed research will open the avenues for including the effect of elongational viscosity on design of the equipment for other polymer processing techniques involving elongation-dominated flows such as blow molding and fiber spinning. The software developed in this project will be used in a senior-level course to educate the students on importance of elongational viscosity in polymer processing. For the next three years, a graduate student will spend one month per year at The Dow Chemical Co. to conduct various experiments resulting in additional educational benefit from the project.