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--- en:grundlagenhandbuch:entgasungsoberflaechenberechnung [2026/02/09 20:42] – [Degassing Basic knowledge (Theory)] 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======
-===== Degassing Basic knowledge =====
+==== Material degradation and degassing ====
-Material degradation and degassing
   * Thermal (oxidative, mechanical)
   * Hydrolytic degradation
@@ Zeile 48: / Zeile 47: @@
 The surface (2) is the result of the multiplication of the height and the development of the channel, taking into account that no melt pool is formed in the contact zone.
-$$A_{Pool} = 2 \frac{\pi - \alpha_E}{\pi} \cdot \frac{2hL}{\sin \varphi} \tag{2}$$
+$$A_{Pool} = 2 \frac{\pi - \alpha_F}{\pi} \cdot \frac{2hL}{\sin \varphi} \tag{2}$$
 For the determination of the melt film, the difference of the shell surface of the eight-shaped housing (filled with melt) and comb surfaces of the screw is drawn up, thereby the surface of the film is determined (see equation 3).
-$$A_{Film} = 2 \frac{\pi - \alpha_E}{\pi} D_a \pi L \left(1 - \frac{2e}{t \cos \varphi}\right)(1 - \varepsilon) \tag{3}$$
+$$A_{Film} = 2 \frac{\pi - \alpha_F}{\pi} D_a \pi L \left(1 - \frac{2e}{t \cos \varphi}\right)(1 - \varepsilon) \tag{3}$$
 The surface renewal time is calculated by using Equation (4).
@@ Zeile 106: / 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.