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en:berechnungen:nutbuchsenberechnung [2025/07/03 13:36] – cschallen:berechnungen:nutbuchsenberechnung [2026/05/27 09:59] (aktuell) – [Case differentiation] flbr
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   *  **Case 2a**: The pellet diameter is smaller than the groove depth (incl. screw clearance), there is frictional flow over the entire channel depth; there is no conveying in the grooves themselves. In addition to the purely analytical calculation of conveying case 2a, it is also possible to carry out a numerically corrected calculation. In this case, the analytically determined conveying angle is multiplied by a correction factor based on extensive numerical simulations using the Discrete Element Method (DEM). The following parameters were varied in these simulations: Pellet diameter, friction coefficients, barrel diameter, flight depth, flight pitch, groove angle, screw peripheral speed and back pressure at the end of the grooved bush. For conveying case 2a, the flight depth, flight pitch, groove angle and circumferential speed have proven to be particularly relevant influencing factors on the correction factor and have therefore been implemented. In the varied practice-relevant areas of the test plan, it was found that the conventional analytical calculation predominantly overestimates the throughput because the assumed block flow cannot always be maintained in the DEM simulations. Instead, there is partial sliding of granulate layers, which is taken into account by the ‘numerically corrected’ option.   *  **Case 2a**: The pellet diameter is smaller than the groove depth (incl. screw clearance), there is frictional flow over the entire channel depth; there is no conveying in the grooves themselves. In addition to the purely analytical calculation of conveying case 2a, it is also possible to carry out a numerically corrected calculation. In this case, the analytically determined conveying angle is multiplied by a correction factor based on extensive numerical simulations using the Discrete Element Method (DEM). The following parameters were varied in these simulations: Pellet diameter, friction coefficients, barrel diameter, flight depth, flight pitch, groove angle, screw peripheral speed and back pressure at the end of the grooved bush. For conveying case 2a, the flight depth, flight pitch, groove angle and circumferential speed have proven to be particularly relevant influencing factors on the correction factor and have therefore been implemented. In the varied practice-relevant areas of the test plan, it was found that the conventional analytical calculation predominantly overestimates the throughput because the assumed block flow cannot always be maintained in the DEM simulations. Instead, there is partial sliding of granulate layers, which is taken into account by the ‘numerically corrected’ option.
  
-  *   **Case 2b**: The pellet diameter is much smaller than the groove depth (incl. screw clearance); there is frictional flow over the entire channel depth, whereby there is no conveying in the grooves themselves and a calculation is only possible empirically+  *   **Case 2b**: The pellet diameter is much smaller (all pellet diameters smaller than 1 mm) than the groove depth (incl. screw clearance); there is frictional flow over the entire channel depth, whereby there is no conveying in the grooves themselves and a calculation is only possible empirically
  
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