Particle Simulation for the Conveying Behavior of Granules in Grooved Bushing Extruders

该研究项目的目标是在数值模拟的基础上重新表述槽套区域内输送行为的数学描述。这使得能够在3D环境中检测进料部分中颗粒的复杂运动，从而提高了计算精度。以往的研究表明，用离散元方法可以很好地描述固体输送区的输送机理和能量过程行为。因此，该方法为该方法的应用提供了依据。在模拟中，工艺和材料参数在中心组合设计的帮助下改变，以及螺纹槽和沟槽中的几何参数。另外，通过改变沟槽角度来考虑轴向或螺旋加工的沟槽。在由数值模拟支持的验证研究之后，将执行物理边界的检测。因此，在具有光滑套管区的模拟情况下，可以看到，尽管背压导致颗粒积压，但第一个螺杆飞行可以部分填满。这会导致压力曲线移位，因此整个进料部分的压力不会再增加。在有凹槽的系统上，在足够高的转速下，预计会出现类似的情况。这也需要对现有计算模型进行新的表述。所获得的结果，将最终得到系统的验证。在这里，已经开发了一个测试平台，它将被调整到所需的沟槽衬套系统。通过现有的验证，可以对带槽衬套区域中的输送过程进行广泛的描述。

The goal of the proposed research project is to reformulate the mathematical description of the conveying behavior in grooved bushing zones based on numerical simulations. This enables the possibility to detect the complex movements of the granules in the feed section in a 3D environment and thus improves the calculation accuracy. In previous research projects, it was shown that both, the conveying mechanisms and the energetic process behavior in the solids conveying area, can be well represented using the Discrete Element Method. Therefore, this method provides the basis for this application. In the simulations, process and material parameters are varied with the aid of a centrally composed design as well as geometrical parameters in the screw channel and grooves. Also axially or spiral machined grooves are taken into account by varying the groove angle. Next to verification studies supported by numerical simulations, a detection of physical boundaries will be performed. Thus, in the case of simulations with a smooth bushing zone, it can be seen that, despite a particle backlog, caused by the backpressure, the first screw flights can be partially filled. This leads to a displaced pressure profile, so that the pressure does not increase anymore over the entire feed section. Analogies are expected at sufficiently high rotational speeds on grooved systems. This also requires a new formulation of existing calculation models. The results obtained, will finally be systematically validated. Here, a test stand has been developed which will be adjusted to the desired grooved bushing system. With an existing validation, an extensive description of the conveying processes in grooved bushing zones is possible.