Symbolic regression models for predicting viscous dissipation of three-dimensional non-Newtonian flows in single-screw extruders
Symbolic regression models for predicting viscous dissipation of three-dimensional non-Newtonian flows in single-screw extruders
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DOI：
10.1016/j.jnnfm.2019.04.006
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发表时间：
2019-06-01
影响因子：
3.1
通讯作者：
Miethlinger, Juergen
中科院分区：
文献类型：
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作者：
Roland, Wolfgang;Marschik, Christian;Miethlinger, Juergen
单螺杆挤出机中非牛顿熔体流动的模拟通常需要数值方法。在这项研究中，我们分析了非牛顿流体在单螺杆挤出机的三维计量通道内充分发展的流动的粘性耗散。应用相似理论，我们确定了一组四个独立的无量纲影响参数，充分描述了所考虑的问题的基本物理：通道高宽比h/w，螺距比t/D-b，幂律指数n，和无量纲通道压力梯度Pi（p，z）。基于一个全面的数值参数设计研究，我们开发了两个广义符号回归模型预测无量纲粘性耗散-一个给定的压力梯度，另一个给定的吞吐量。作为三维建模方法的结果，我们的回归模型考虑了飞行侧翼、横向流动和非牛顿流体行为的影响。这些开发的模型的准确性得到了证明，通过使用一个独立的数据集的误差分析。这些模型可以快速、稳定和准确地预测粘性耗散，从而有助于挤出机螺杆的优化设计，而无需进行数值模拟。此外，它们适用于注塑机和预测所需的驱动功率。
Modeling the flow of non-Newtonian melts in single-screw extruders generally requires numerical methods. In this study, we analyze viscous dissipation for fully developed flow of non-Newtonian fluids within three-dimensional metering channels of single-screw extruders. Applying the theory of similarity we identified a set of four independent dimensionless influencing parameters that fully describe the underlying physics of the considered problem: the channel height-to-width ratio h/w, the screw-pitch ratio t/D-b, the power-law exponent n, and the dimensionless down-channel pressure gradient Pi(p, z). Based on a comprehensive numerical parametric design study we developed two generalized symbolic regression models predicting dimensionless viscous dissipation - one for given pressure gradient, and the other one for given throughput. As a result of the three-dimensional modeling approach our regression models take the effects of flight flanks, transverse flow, and non-Newtonian fluid behavior into account. The accuracy of these developed models was proven by means of an error analysis using an independent data set. These models allow fast, stable and accurate predictions of viscous dissipation, thus contributing to the optimal design of extruder screws without the need for numerical simulations. Furthermore they are applicable to injection molding machines and for predicting the required drive power.