Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
| Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende Überarbeitung | ||
| en:berechnungen:feststofffoerderung [2024/07/23 19:08] – neelest | en:berechnungen:feststofffoerderung [2025/09/03 12:56] (aktuell) – [Application in REX] neelest | ||
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| - | ======Solids conveying ====== | + | ====== Solids conveying ====== |
| - | Wichtig: Was ist der unterschied zur Seite [[berechnungen: | + | =====Consideration of solids transport===== |
| - | FIXME | + | In REX, //solids conveying// refers to the consideration of the pressure-throughput behaviour of pellet conveying in the feed area of a smooth tube extruder. \\ |
| - | + | When modelling the pressure set, not only the maximum (back pressure-dependent) throughput within the screw ($\dot m_{Schneider}$), but also the limited trickling behaviour ($\dot m_{max}$) is taken into account. The combination of these two models results in the back pressure-dependent throughput of the entire feed zone (red curve) considered in REX. | |
| - | ===== Solids conveying ===== | + | |
| - | + | ||
| - | In REX, ‘solids conveying’ refers to the consideration of the pressure-throughput behaviour of pellet conveying in the feed area of a smooth tube extruder. \\ | + | |
| - | When modelling the pressure set, not only the maximum (back pressure-dependent) throughput within the screw ($\dot m_{cutter}$), but also the limited trickling behaviour ($\dot m_{max}$) is taken into account. The combination of these two models results in the back pressure-dependent throughput of the entire feed zone (red curve) considered in REX. | + | |
| {{ : | {{ : | ||
| Zeile 27: | Zeile 23: | ||
| Based on the throughput calculation according to // | Based on the throughput calculation according to // | ||
| - | $N_ü = \frac{\dot m_{max}}{\rho_s*B*h*\pi*D}*\frac{sin(\alpha+\varphi)}{sin(\alpha)}$ | + | $N_ü = \frac{\dot m_{max}}{\rho_s*A*\pi*D}*\frac{tan(\alpha)+tan(\varphi)}{tan(\alpha)*tan(\varphi)}$ |
| - | with the bulk density $\rho_s$, the channel | + | 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 | ||
| < | < | ||
| - | * Trippe, Jan Klaus: | + | * Trippe, Jan Klaus: |
| - | * Schneider, K.: The conveying process | + | * Schneider, K.: Der Fördervorgang |
| </ | </ | ||
| Zeile 41: | 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: |
| - | 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 |
| - | 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 |
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| The warning message appears if the entry flow rate $m_{max}$ is less than 1.25 times the calculated flow rate. This is to warn of possible underfeeding. | The warning message appears if the entry flow rate $m_{max}$ is less than 1.25 times the calculated flow rate. This is to warn of possible underfeeding. | ||
| + | ===Further topics=== | ||
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