Abstract The separation of different kind of plastic particles is required in the process of waste recycling. For the separation, drum processes with liquid can be used. The separation is based on the principle that particles either sink or float in a liquid depending on their densities. In this study, this process is numerically analysed for the separation of polyethylene terephthalate (PET) from polypropylene (PP) particles. The discrete element method coupled with the smoothed particle hydrodynamics method (DEM-SPH) is used for modelling purposes. The employment of the SPH for the modelling of the liquid exploits the strong side of this meshless method, namely, the relative ease in modelling large movements of the fluid with free surfaces and moving boundaries. This theoretical model is presented, and verification tests are performed, where a dam-break problem is considered as an example. Simulations of the plastic particle separation in the rotating drum are performed thereafter. The influences of the different operational and design parameters, such as the rotational velocity, feed rate, and number of lifters on the resultant purity of the plastic are estimated. It is expected that, in the future, the performed analysis will allow the numerical optimisation of drum separation processes.

中文翻译：

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使用耦合 DEM-SPH 方法进行湿塑料颗粒分离的数值分析

摘要 在废物回收过程中，需要对不同种类的塑料颗粒进行分离。对于分离，可以使用带有液体的鼓式工艺。分离是基于粒子根据其密度在液体中下沉或漂浮的原理。在本研究中，对该过程进行了数值分析，以从聚丙烯 (PP) 颗粒中分离聚对苯二甲酸乙二醇酯 (PET)。离散元方法与平滑粒子流体动力学方法 (DEM-SPH) 结合用于建模。使用 SPH 进行液体建模利用了这种无网格方法的优势，即相对容易模拟具有自由表面和移动边界的流体的大运动。提出了这个理论模型，并进行了验证测试，其中以溃坝问题为例。此后进行转鼓中塑料颗粒分离的模拟。估计了不同的操作和设计参数，如旋转速度、进料速度和提升器数量对塑料合成纯度的影响。预计在未来，所进行的分析将允许对鼓分离过程进行数值优化。