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Nächste Überarbeitung		Vorhergehende Überarbeitung
en:berechnungen:feststofffoerderung [2025/01/13 18:40] – [Consideration of solids transport] neelesten:berechnungen:feststofffoerderung [2025/09/03 12:56] (aktuell) – [Application in REX] neelest
Zeile 23: Zeile 23:
 Based on the throughput calculation according to //Schneider//, which is not reproduced in detail here, the transition speed $N_ü$ is now calculated as follows: Based on the throughput calculation according to //Schneider//, which is not reproduced in detail here, the transition speed $N_ü$ is now calculated as follows:
  
-$N_ü = \frac{\dot m_{max}}{\rho_s*B*h*\pi*D}*\frac{sin(\alpha+\varphi)}{sin(\alpha)}$+$N_ü = \frac{\dot m_{max}}{\rho_s*A*\pi*D}*\frac{tan(\alpha)+tan(\varphi)}{tan(\alpha)*tan(\varphi)}$
  
-with the bulk density $\rho_s$, the channel width $B$, the channel depth $h$, the diameter $D$, the back pressure-dependent solids conveying angle according to //Schneider// $\alpha$ and the pitch angle $\varphi$.+with 
 + 
 +$A = \frac{\pi}{4}*(D^2-D_K^2)-\frac{i*e*h}{sin(\overline{\varphi})}$ 
 + 
 +with the bulk density $\rho_s$, the screw diameter $D$, the screw core diameter $D_K$, the cross-sectional area $A$, the flight width $e$, the number of flights $i$, the channel depth $h$, the back-pressure-dependent solid conveying angle according to //Schneider// $\alpha$, and the helix angle $\varphi$.
  
 <details><summary>Sources</summary> <details><summary>Sources</summary>
-  * Trippe, Jan Klaus: Extension of the modelling for throughput and performance calculation of solids conveying processes in single-screw extrusion, dissertation, University of Paderborn, 2018 +  * Trippe, Jan Klaus: Erweiterung der Modellierung zur Durchsatz- und Leistungsberechnung von Feststoffförderprozessen in der Einschneckenextrusion, Dissertation, Universität Paderborn, 2018 
-  * Schneider, K.: The conveying process in the feed zone of an extruder, dissertation, RWTH Aachen University, 1968+  * Schneider, K.: Der Fördervorgang in der Einzugszone eines Extruders, Dissertation, RWTH Aachen, 1968
 </details> </details>
  
Zeile 37: Zeile 41:
 If the calculation setting for the throughput ‘Coupling solids conveying’ is selected, the calculation in REX/PSI is performed as follows: If the calculation setting for the throughput ‘Coupling solids conveying’ is selected, the calculation in REX/PSI is performed as follows:
  
-Firstly, the melt-dominated throughput without solids conveying is calculated. From this, the pressure at the start of the first heating zone is calculated back from the screw tip and the known back pressure. The start of the first heating zone is assumed to be the location up to which there is pure solids conveying and therefore serves as the interface between melt conveying and solids conveying.\\\ +Firstly, the melt-dominated throughput without solids conveying is calculated. From this, the pressure at the [[en:berechnungen:aufschmelzverlauf|melt vortex formation]] is calculated back from the screw tip and the known back pressure. The melt vortex formation is assumed to be the location up to which there is pure solids conveying and therefore serves as the interface between melt conveying and solids conveying.\\ 
-Based on the known location and pressure at the start of the first heating zone, the solids conveying throughput can then be calculated. This can be higher or lower than the melt-dominated calculated throughput. +Based on the known location and pressure at the melt vortex formation, the solids conveying throughput can then be calculated. This can be higher or lower than the melt-dominated calculated throughput. 
-If the calculated throughput is lower, the pressure at the start of the first heating zone is recalculated with a reduced throughput from the tip of the leg. The back pressure of the solids conveying zone is therefore lower and the solids conveying throughput is therefore higher. \\ +If the calculated throughput is lower, the pressure at the melt vortex formation is recalculated with a reduced throughput from the tip of the leg. The back pressure of the solids conveying zone is therefore lower and the solids conveying throughput is therefore higher. \\ 
-The flow rate is now iterated until the pressure at the start of the first heating zone is reached, for which the melt-dominated flow rate and the solids conveying flow rate are identical.+The flow rate is now iterated until the pressure at the melt vortex formation is reached, for which the melt-dominated flow rate and the solids conveying flow rate are identical.
 \\ \\
 \\ \\
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 ===Further topics=== ===Further topics===
   * [[en:berechnungen:einfache_berechnung|]]   * [[en:berechnungen:einfache_berechnung|]]
 +  * [[en:berechnungen:prozess_iterieren]]
   * [[en:berechnungen:durchsatz|]]   * [[en:berechnungen:durchsatz|]]
   * [[en:berechnungen:druckverlauf|]]   * [[en:berechnungen:druckverlauf|]]
Zeile 60: Zeile 65:
   * [[en:berechnungen:temperaturverlauf|]]   * [[en:berechnungen:temperaturverlauf|]]
   * [[en:berechnungen:leistung_und_schubspannungen|]]   * [[en:berechnungen:leistung_und_schubspannungen|]]
 +  * [[en:berechnungen:schergeschwindigkeit]]
   * [[en:berechnungen:verweilzeit|]]   * [[en:berechnungen:verweilzeit|]]
   * [[en:berechnungen:verweilzeitverteilung|]]   * [[en:berechnungen:verweilzeitverteilung|]]