Fill degree is a key parameter impacting twin screw extruders' (TSEs) mixing performance and melting behavior. The conventional conveying model of partially filled fluid relies mainly on empirical methods. A nontwin screw geometry introduces a speed difference between the two intermeshing screws to change the conveying means, and this speed difference offers a challenge for establishing a new conveying model. A visualization prototype with a global transparent barrel was developed in this article with carboxymethylcellulose sodium solution used as working fluid. Fill length was measured under different outputs and screw rotation speeds in a nontwin screw channel versus a corresponding twin screw channel; thus, fill degree was obtained using the observed fill lengths and nontwin screw geometries. A new conveying model of partially filled fluid was proposed which isolated positive displacement flow as an independent factor, and visualization observations revealed that due to differences in screw flight width, the positive displacement flow in a nontwin screw channel is larger than that in a traditional twin‐screw channel. Results showed that dimensionless positive displacement conveying increased linearly with fill degree for a non‐TSE geometry while it was independent of fill degree for a TSE geometry. POLYM. ENG. SCI., 60:151–160, 2020. © 2019 Society of Plastics Engineers

中文翻译：

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部分填充非双螺杆挤出机中允许正排量的流体输送模型

填充度是影响双螺杆挤出机（TSE）混合性能和熔融行为的关键参数。常规的部分填充流体输送模型主要依靠经验方法。非双螺杆几何形状在两个相互啮合的螺杆之间引入了速度差以改变输送方式，并且这种速度差为建立新的输送模型提出了挑战。本文使用羧甲基纤维素钠溶液作为工作流体，开发了具有全局透明桶的可视化原型。在非双螺杆通道相对于相应的双螺杆通道中，在不同的输出和螺杆转速下测量填充长度。因此，使用观察到的填充长度和非双螺杆几何形状即可获得填充度。提出了一种新的部分填充流体输送模型，该模型将正排量流作为一个独立因素进行隔离，可视化观察表明，由于螺杆螺距的不同，非双螺旋通道中的正排量要大于传统双螺旋管中的正排量。螺丝通道。结果表明，对于非TSE几何形状，无量纲正位移输送随填充度线性增加，而与TSE几何形状的填充度无关。POLYM。ENG。SCI。，60：151–160，2020.©2019塑料工程师协会 非双螺杆通道的正排量流量要大于传统双螺杆通道的正排量流量。结果表明，对于非TSE几何形状，无量纲正位移输送随填充度线性增加，而与TSE几何形状的填充度无关。POLYM。ENG。SCI。，60：151–160，2020.©2019塑料工程师协会 非双螺杆通道的正排量流量要大于传统双螺杆通道的正排量流量。结果表明，对于非TSE几何形状，无量纲正位移输送随填充度线性增加，而与TSE几何形状的填充度无关。POLYM。ENG。SCI。，60：151–160，2020.©2019塑料工程师协会