Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
| Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende Überarbeitung | ||
| en:grundlagenhandbuch:aufschmelzberechnung [2026/09/04 08:36] – [Phenomenology] paal | en:grundlagenhandbuch:aufschmelzberechnung [2026/09/04 09:40] (aktuell) – [Temperature of the Solids at the Location of the First Melt] paal | ||
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| Zeile 2: | Zeile 2: | ||
| ===== Phenomenology===== | ===== Phenomenology===== | ||
| - | The feed material is held in underneath the hopper opening by the screw-elements and is transported in the screws as a solid in the direction of the screw-tips. Through contact with the heated cylinder wall, the particles in the proximity of the cylinder wall begin to sinter and melt on until finally a broad standing connected | + | The feed material is held in underneath the hopper opening by the screw-elements and is transported in the screws as a solid in the direction of the screw-tips. Through contact with the heated cylinder wall, the particles in the proximity of the cylinder wall begin to sinter and melt on until finally a continuous |
| - | Through the formation of the molten film, the friction conditions in the mesh area and in the solid tailback change behind the intermeshing area. Through this process, the forced conveying of solids in a intermeshing region breaks down, and material is forced through the nip region. As a result of the 3-dimensional speed profile in the intermeshing area, an intensive mixture of the materials occurs. If the proportion of ready-fused materials is sufficient, a dispersion from the existing granules is formed from the solid phase and from the existing viscous phase polymer melt. | + | Through the formation of the molten film, the friction conditions in the mesh area and in the solid tailback change behind the intermeshing area. Through this process, the forced conveying of solids in an intermeshing region breaks down, and material is forced through the nip region. As a result of the 3-dimensional speed profile in the intermeshing area, an intensive mixture of the materials occurs. If the proportion of ready-fused materials is sufficient, a dispersion from the existing granules is formed from the solid phase and from the existing viscous phase polymer melt. |
| - | If the melted share for a completely formed dispersion is not yet sufficient an agglomeration of granule particles occurs. These are then further fused through the dissipation of the already existing melt, and through heat conduction of the surrounding walls. Also the agglomerates | + | If the melted share for a completely formed dispersion is not yet sufficient an agglomeration of granule particles occurs. These are then further fused through the dissipation of the already existing melt, and through heat conduction of the surrounding walls. Also the agglomerates |
| - | After the achievement of this condition, the further melting of the not yet molten Polymer particles can only be successful through the heat conduction from the hot melt to the solid granule particles. This is because the granule particles no longer have direct contact with the heated cylinder walls, i.e. they are longer | + | After the achievement of this condition, the further melting of the not yet molten Polymer particles can only be successful through the heat conduction from the hot melt to the solid granule particles. This is because the granule particles no longer have direct contact with the heated cylinder walls, i.e. they no longer |
| - | A condition for the described melting behavior is a sufficiently long solids-conveying section. | + | A condition for the described melting behavior is a sufficiently long solids-conveying section. |
| If the available length of conveying section to the molten film over the solid tail-back does not suffice, so the forced conveying of the solids remains up to the location where the first filling with melt took place. Principally, | If the available length of conveying section to the molten film over the solid tail-back does not suffice, so the forced conveying of the solids remains up to the location where the first filling with melt took place. Principally, | ||
| Zeile 102: | Zeile 102: | ||
| The coupling of the energy theorem and kinetics gives the differential calculus for the spherically symmetric temperature field. | The coupling of the energy theorem and kinetics gives the differential calculus for the spherically symmetric temperature field. | ||
| - | $$\frac{\partial \theta}{\partial \tau} = \frac{1 | + | $$\frac{\partial\theta}{\partial\tau} = \frac{1}{\xi^2}\frac{\partial}{\partial\xi}\left(\xi^2\frac{\partial\theta}{\partial\xi}\right)\tag{12}$$ |
| - | whereby these standardization' | + | whereby these standardizations: |
| $$\theta = \frac{T - T_0}{T_0 - T_U} ; \tau = \frac{at}{r_0^2} ; \xi = \frac{r}{r_0} \tag{13}$$ | $$\theta = \frac{T - T_0}{T_0 - T_U} ; \tau = \frac{at}{r_0^2} ; \xi = \frac{r}{r_0} \tag{13}$$ | ||
| Zeile 118: | Zeile 118: | ||
| and the boundary conditions | and the boundary conditions | ||
| - | $$\left(\frac{1}{Bi} \frac{\partial \theta}{\partial \xi} + \theta\right)_{\xi=1} = \begin{cases}1 \text{ | + | $$\left(\frac{1}{Bi} \frac{\partial \theta}{\partial \xi} + \theta\right)_{\xi=1} = \begin{cases}1 \text{ |
| as a solution of the average caloric temperature of the particle: | as a solution of the average caloric temperature of the particle: | ||