Unterschiede

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--- en:grundlagenhandbuch:entgasungsoberflaechenberechnung [2026/02/09 20:51] – [Model for calculating the free surface] neelest
+++ en:grundlagenhandbuch:entgasungsoberflaechenberechnung [2026/08/03 13:36] (aktuell) – [Degassing efficiency of the process] paal
@@ Zeile 1: / Zeile 1: @@
 ====== Calculation of the degassing surface======
-===== Material degradation and degassing =====
+==== Material degradation and degassing ====
   * Thermal (oxidative, mechanical)
@@ Zeile 27: / Zeile 27: @@
 Decisive for a successful degassing are the applied vacuum and the surface of the melt in the screw channel.
-===== Model for calculating the free surface =====
+==== Model for calculating the free surface ====
 The free surface is composed of the melt pool and melt film, which are constantly renewed by the continuous rotation of the screws.
@@ Zeile 105: / Zeile 105: @@
 ===== Degassing efficiency of the process =====
-The degassing efficiency is evaluated with the degassing reference parameter of Schuler (Equation 1. In this case taken place the determination for wetting and non-wetting polymer.
+The degassing performance can be calculated using the following equation:
-$$\frac{c_{Start} - c_{End}}{c_{Start} - c_{Gleichgewicht}} = \frac{\left(\frac{A_{POOL}}{t_{POOL}} + \frac{A_{FILM}}{t_{FILM}} + \frac{A_{GRUND}}{t_{GRUND}}\right)}{\dot{m}} \tag{Equation 1}$$
+$$\eta^* = \frac{c_{Start} - c_{End}}{c_{Start} - c_{Equilibrium}} = 2\rho\sqrt{ \frac{ D }{ \pi } } \frac{\left(\frac{A_{POOL}}{\sqrt{t_{POOL}}} + \frac{A_{FILM}}{\sqrt{t_{FILM}}} + \frac{A_{GROUND}}{\sqrt{t_{GROUND}}}\right)}{\dot{m}} \tag{8}$$
 After transposing of the equation can be the end concentration of low molecular component determined. Thereby is it possible to take a statement about the degassing efficiency.
+The degassing efficiency is evaluated with the degassing reference parameter of Schuler (Equation 9).
-For wetting polymer is the Equation 2and for non-wetting polymer is the Equation 3 used.
+$$\frac{c_{Start} - c_{End}}{c_{Start} - c_{Equilibrium}} \sim \frac{\left(\frac{A_{POOL}}{\sqrt{t_{POOL}}} + \frac{A_{FILM}}{\sqrt{t_{FILM}}} + \frac{A_{GROUND}}{\sqrt{t_{GROUND}}}\right)}{\dot{m}} \tag{9}$$
-$$EK_{Benetzend} = \frac{\left(\frac{A_{POOL}}{t_{POOL}} + \frac{A_{FILM}}{t_{FILM}} + \frac{A_{GRUND}}{t_{GRUND}}\right)}{\dot{m}} \tag{Equation 2}$$
+In this case taken place the determination for wetting and non-wetting polymer. For wetting polymer is the Equation 10 and for non-wetting polymer is the Equation 11 used.
-$$EK_{Nicht-Benetzend} = \frac{\left(\frac{A_{POOL}}{t_{POOL}} + \frac{A_{FILM}}{t_{FILM}}\right)}{\dot{m}} \tag{Equation 3}$$
+$$EK_{Wetting} = \frac{\left(\frac{A_{POOL}}{\sqrt{t_{POOL}}} + \frac{A_{FILM}}{\sqrt{t_{FILM}}} + \frac{A_{GROUND}}{\sqrt{t_{GROUND}}}\right)}{\dot{m}} \tag{10}$$
+$$EK_{Non-Wetting} = \frac{\left(\frac{A_{POOL}}{\sqrt{t_{POOL}}} + \frac{A_{FILM}}{\sqrt{t_{FILM}}}\right)}{\dot{m}} \tag{11}$$
 The difference between both equation is that the surface area und renewal time at screw root is neglected, because in non-wetting case are not melt at screw root available.