Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
| Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende Überarbeitung | ||
| en:grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders [2026/05/24 09:00] – [Free Cross Section and Average Channel Depth] neelest | en:grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders [2026/06/16 14:37] (aktuell) – [Geometry of Tightly Intermeshing, Co-rotating Twin Screw Extruders] deppe2 | ||
|---|---|---|---|
| Zeile 9: | Zeile 9: | ||
| * Modular setup of both screw and barrel (see figure) | * Modular setup of both screw and barrel (see figure) | ||
| - | {{ : | + | {{ :en: |
| **Figure:** Modular setup of both screw and barre | **Figure:** Modular setup of both screw and barre | ||
| Zeile 278: | Zeile 278: | ||
| This area can be calculated according to Booy [[en: | This area can be calculated according to Booy [[en: | ||
| - | $$A_{zw} = \left(\frac{D_s}{2}\right)^2 \cdot \sin(\Omega) - \frac{A_{Fr}}{i} \cdot \left(1 - \frac{\phi \cdot i}{\pi}\right)\tag{10}$$ | + | $$A_{zw} = \left(\frac{D_s}{2}\right)^2 \cdot \sin(\Omega) - \frac{A_{Fr}}{i} \cdot \left(1 - \frac{\phi \cdot i}{\pi}\right)\tag{33}$$ |
| ==== Shouldered Kneading Blocks ==== | ==== Shouldered Kneading Blocks ==== | ||
| Zeile 288: | Zeile 288: | ||
| The model for the traditional kneading blocks, is based on the replacement of the discrete geometry (kneading discs) with a continuous geometry. One can find grooves within flights of this assumed continuous geometry. These grooves are characterized by their height $h_{Nut}$, their length $l_{Nut}$ and their width $b_{Nut}$. The width is half the width of the discs of traditional kneading blocks ($b_{Kn}$). | The model for the traditional kneading blocks, is based on the replacement of the discrete geometry (kneading discs) with a continuous geometry. One can find grooves within flights of this assumed continuous geometry. These grooves are characterized by their height $h_{Nut}$, their length $l_{Nut}$ and their width $b_{Nut}$. The width is half the width of the discs of traditional kneading blocks ($b_{Kn}$). | ||
| - | $$b_{groove} = \frac{1}{2} \cdot b_{Kn} \tag{11}$$ | + | $$b_{groove} = \frac{1}{2} \cdot b_{Kn} \tag{34}$$ |
| - | $$l_{groove} = \frac{e}{\cos \varphi_s}\tag{12}$$ | + | $$l_{groove} = \frac{e}{\cos \varphi_s}\tag{35}$$ |
| The height of the groove results from the staggering angle. The staggering angle needs to be larger than the flight angle in order to form a groove. If the staggering angle is smaller than the flight angle then no groove can be calculated. | The height of the groove results from the staggering angle. The staggering angle needs to be larger than the flight angle in order to form a groove. If the staggering angle is smaller than the flight angle then no groove can be calculated. | ||
| Zeile 296: | Zeile 296: | ||
| For staggering $\Phi \leq \alpha \leq 45°$ we use a linear relationship between staggering angle and depth of the groove. After conducting experimental investigations we found that it is necessary to apply a factor of 0.5 to that relationship. | For staggering $\Phi \leq \alpha \leq 45°$ we use a linear relationship between staggering angle and depth of the groove. After conducting experimental investigations we found that it is necessary to apply a factor of 0.5 to that relationship. | ||
| - | $$h_{groove} = 0.5 \cdot \left(\frac{\bar{h}}{\frac{1}{4} \cdot \pi - \Phi} \cdot \alpha - \frac{\Phi \cdot \bar{h}}{\frac{1}{4} \cdot \pi - \Phi} + s_R\right)\tag{13}$$ | + | $$h_{groove} = 0.5 \cdot \left(\frac{\bar{h}}{\frac{1}{4} \cdot \pi - \Phi} \cdot \alpha - \frac{\Phi \cdot \bar{h}}{\frac{1}{4} \cdot \pi - \Phi} + s_R\right)\tag{36}$$ |
| {{ : | {{ : | ||
| Zeile 304: | Zeile 304: | ||
| The channel model for conveying shouldered kneading blocks is shown in the figure. We get the following equilibrium of flow rates within the control volume A-B-C: | The channel model for conveying shouldered kneading blocks is shown in the figure. We get the following equilibrium of flow rates within the control volume A-B-C: | ||
| - | $$\dot{V} = k \cdot \dot{V}_{channel} \pm \dot{V}_{gap} \pm l \cdot \dot{V}_{groove}\tag{14}$$ | + | $$\dot{V} = k \cdot \dot{V}_{channel} \pm \dot{V}_{gap} \pm l \cdot \dot{V}_{groove}\tag{37}$$ |
| Where $l$ is the number of grooves between the points A and B. The number of the grooves corresponds to the number of kneading discs per rotation, hence follows: | Where $l$ is the number of grooves between the points A and B. The number of the grooves corresponds to the number of kneading discs per rotation, hence follows: | ||
| - | $$l = \frac{b_{Kn}}{2 \cdot \pi} \cdot (2 \cdot \pi - \Omega) \cdot \cos \varphi_s\tag{15}$$ | + | $$l = \frac{b_{Kn}}{2 \cdot \pi} \cdot (2 \cdot \pi - \Omega) \cdot \cos \varphi_s\tag{38}$$ |
| With $b_{Kn}$ being the width of the kneading discs. | With $b_{Kn}$ being the width of the kneading discs. | ||
| Zeile 314: | Zeile 314: | ||
| The width of the flights $b_{Steg}$ is shortened by the total sum of all groove widths $l$. | The width of the flights $b_{Steg}$ is shortened by the total sum of all groove widths $l$. | ||
| - | $$b_{threads} = (2 \cdot \pi - \Omega) \cdot D_s \cdot \cos \varphi_s - l \cdot b_{groove}\tag{16}$$ | + | $$b_{threads} = (2 \cdot \pi - \Omega) \cdot D_s \cdot \cos \varphi_s - l \cdot b_{groove}\tag{39}$$ |
| ==== Eccentric Kneading Blocks ==== | ==== Eccentric Kneading Blocks ==== | ||
| Zeile 330: | Zeile 330: | ||
| Maximum diameter ratio of three-way profile ($i=3$) | Maximum diameter ratio of three-way profile ($i=3$) | ||
| - | $$D_{v,3} = D_{v,3,max} = \frac{1}{2 \cdot \cos\left(\frac{\pi}{2 \cdot 3}\right) - 1} = 1.366 \tag{Equation 3-13}$$ | + | $$D_{v,3} = D_{v,3,max} = \frac{1}{2 \cdot \cos\left(\frac{\pi}{2 \cdot 3}\right) - 1} = 1.366 \tag{40}$$ |
| Outer diameter of three-course profile | Outer diameter of three-course profile | ||
| - | $$D_{a,3} = \frac{2 \cdot a}{1 + D_{v,3}} \tag{Equation 3-14}$$ | + | $$D_{a,3} = \frac{2 \cdot a}{1 + D_{v,3}} \tag{41}$$ |
| Eccentricity $e$ | Eccentricity $e$ | ||
| - | $$e = \frac{D_{a, | + | $$e = \frac{D_{a, |
| Inside diameter of three-course profile | Inside diameter of three-course profile | ||
| - | $$D_{i,3} = 2 \cdot a - D_{a,3} \tag{Equation 3-16}$$ | + | $$D_{i,3} = 2 \cdot a - D_{a,3} \tag{43}$$ |
| Zeile 352: | Zeile 352: | ||
| This profile shows that the comb angles are zero. Therefore the flank angles of the standard profile are the same: | This profile shows that the comb angles are zero. Therefore the flank angles of the standard profile are the same: | ||
| - | Comb angle: $\angle AOB = \angle BOC = \angle COD = \Omega_3 = 60° \tag{Equation 3-17}$ | + | Comb angle: |
| - | Flank angle: $\phi_{k,3} = \phi_{g,3} = 0 \tag{Equation 3-18}$ | + | Flank angle: |
| - | Outside radius: $R_{a,3} = \frac{D_{a, | + | Outside radius: |
| - | Inside radius: $R_{i,3} = \frac{D_{i, | + | Inside radius: |
| The coordinates of the points in the three-course standard profile can be calculated by these geometry sizes. Because the profile is symmetrical, | The coordinates of the points in the three-course standard profile can be calculated by these geometry sizes. Because the profile is symmetrical, | ||
| - | A: $x_A = R_{i,3}$; $y_A = 0$ | + | A: $x_A = R_{i,3}; y_A = 0\tag{48}$ |
| - | B: $x_B = R_{a,3} \cdot \cos 60° = \frac{1}{2}R_{a, | + | B: $x_B = R_{a,3} \cdot \cos 60° = \frac{1}{2}R_{a, |
| - | C: $x_C = R_{i,3} \cdot \cos 120° = -\frac{1}{2}R_{i, | + | C: $x_C = R_{i,3} \cdot \cos 120° = -\frac{1}{2}R_{i, |
| - | D: $x_D = -R_{a,3}$; $y_D = 0$ | + | D: $x_D = -R_{a,3}; y_D = 0\tag{51}$ |
| ==== Screw Mixing Elements ==== | ==== Screw Mixing Elements ==== | ||
| Zeile 386: | Zeile 386: | ||
| From the control volume ABC we get the equilibrium of flow rates: | From the control volume ABC we get the equilibrium of flow rates: | ||
| - | $$\dot{V} = k \cdot \dot{V}_{channel} \pm \dot{V}_{gap} \pm l \cdot \dot{V}_{groove}\tag{21}$$ | + | $$\dot{V} = k \cdot \dot{V}_{channel} \pm \dot{V}_{gap} \pm l \cdot \dot{V}_{groove}\tag{52}$$ |
| Where $l$ is the number of grooves between the points A and B. $l$ is calculated using the following equation: | Where $l$ is the number of grooves between the points A and B. $l$ is calculated using the following equation: | ||
| - | $$l = \frac{l_{Nut}}{2\pi} \cdot (2\pi - \Omega) \cdot \cos \varphi_s\tag{22}$$ | + | $$l = \frac{l_{Nut}}{2\pi} \cdot (2\pi - \Omega) \cdot \cos \varphi_s\tag{53}$$ |
| ==== Blister Elements ==== | ==== Blister Elements ==== | ||
| Zeile 415: | Zeile 415: | ||
| These sections are characterized by the following dimensionless numbers: | These sections are characterized by the following dimensionless numbers: | ||
| - | $$k_1 = \frac{D_a}{D_z}\tag{23}$$ | + | $$k_1 = \frac{D_a}{D_z}\tag{54}$$ |
| - | $$k_2 = \frac{D_i}{D_a}\tag{24}$$ | + | $$k_2 = \frac{D_i}{D_a}\tag{55}$$ |
| - | $$cl = \frac{a}{D_z/ | + | $$cl = \frac{a}{D_z/ |
| ==== Thoothed Mixing Elements ==== | ==== Thoothed Mixing Elements ==== | ||