Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
| Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende Überarbeitung | ||
| en:berechnungen:leistung_und_schubspannungen [2024/10/17 20:11] – [Power and wall shear stress] neelest | en:berechnungen:leistung_und_schubspannungen [2026/09/17 12:46] (aktuell) – gelöscht - Externe Bearbeitung (Unbekanntes Datum) 127.0.0.1 | ||
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| - | ======Power and wall shear stress====== | ||
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| - | The same conditions have to be filled for the calculation of the power and wall shear | ||
| - | stress as for the calculation of the melting profile. | ||
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| - | **Realization of the theoretical principles** | ||
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| - | In the power calculation a distinction is drawn between the incipient fusing and the | ||
| - | melting section. In the incipient fusing section, i. e. from the start of the first heating | ||
| - | section through to the point of melt pool formation, the power can be established via | ||
| - | an average melt layer thickness, assuming a pure drag flow in the melt film. The | ||
| - | power conversion in the pure solids section between the hopper and the first heating | ||
| - | section is neglected, since no pressure has built up till then and the frictional forces of | ||
| - | the solids at the barrel wall are negligibly small compared to the frictional forces of | ||
| - | the melt film. | ||
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| - | The calculation for the other sections results in an addition of the wall shear stresses | ||
| - | at the barrel. Similar to the calculation of the pressure throughput approximation | ||
| - | equations are used, which are based on numeric examinations. A distinction is drawn | ||
| - | between the melting section, where high wall shear stresses in the melt film occur | ||
| - | and the pure melt conveying. | ||
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| - | The overall drive power required (without transmission losses) and the overall torque | ||
| - | is calculated from the local power requirement. | ||
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| - | The heating/ | ||
| - | pool. The temperature gradient at the barrel wall is established for both sections and | ||
| - | from this the necessary heating/ | ||
| - | balance. The power at each single calculation point is added up for the heating | ||
| - | section in question. The heating/ | ||
| - | flow between the band heater and the melt, but not for any heat losses (of any type) | ||
| - | towards the outside. | ||
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| - | ===Further topics=== | ||
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