Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
| Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende Überarbeitung | ||
| en:grundlagenhandbuch:drehmoment_und_antriebsleistung [2026/06/16 11:08] – [Total drive power] neelest | en:grundlagenhandbuch:drehmoment_und_antriebsleistung [2026/06/16 11:11] (aktuell) – [Enthalpy model with heat flow] neelest | ||
|---|---|---|---|
| Zeile 421: | Zeile 421: | ||
| The enthalpy model neglects the heat flow between the polymer and the barrel wall. While in larger industrial extruders the proportion of heating power to total power is small compared to the drive power, neglecting the heat flow can lead to significant errors, particularly in smaller laboratory extruders or processes with a large temperature difference between the melt and the barrel. | The enthalpy model neglects the heat flow between the polymer and the barrel wall. While in larger industrial extruders the proportion of heating power to total power is small compared to the drive power, neglecting the heat flow can lead to significant errors, particularly in smaller laboratory extruders or processes with a large temperature difference between the melt and the barrel. | ||
| - | To account for the heat flow, the heat transfer coefficient is calculated according to FIXME[TM00]. First, the Brinkmann number is calculated and then the Nusselt number is regressed from it. | + | To account for the heat flow, the heat transfer coefficient is calculated according to [[en: |
| $$Br=\frac{K*v_{0}^{n+1}}{\lambda*\Delta T*h^{n-1}}\tag{60}$$ | $$Br=\frac{K*v_{0}^{n+1}}{\lambda*\Delta T*h^{n-1}}\tag{60}$$ | ||
| Zeile 429: | Zeile 429: | ||
| The heat transfer coefficient can then be calculated using the thermal conductivity of the melt and the channel height: | The heat transfer coefficient can then be calculated using the thermal conductivity of the melt and the channel height: | ||
| - | $$α=fraq{Nu*λ}{h}\tag{62}$$ | + | $$\alpha=\frac{Nu*\lambda}{h}\tag{62}$$ |
| The heat flow is calculated as follows: | The heat flow is calculated as follows: | ||
| Zeile 459: | Zeile 459: | ||
| [TK78] Tadmor, Z.; Klein, I: Engineering Principles of Plasticating Extrusion, Robert E. Krieger Publishing Company, Huntington, New York, 1978 | [TK78] Tadmor, Z.; Klein, I: Engineering Principles of Plasticating Extrusion, Robert E. Krieger Publishing Company, Huntington, New York, 1978 | ||
| + | |||
| + | [TM00] Tenge, S.; Mewes, D.: “Experimental investigation of the energy balance for the metering zone of a twin screw extruder”; | ||