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en:grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders [2026/05/21 22:28] – [Free Cross Section and Average Channel Depth] neelesten: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)
  
-{{ :grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders:eingesetzte_schneckenelemente:en_sigma150_dlg_grundlagenhandbuch_geometriegroessen_000.svg?700%nolink |}}+{{ :en:grundlagenhandbuch:de_sigma150_dlg_grundlagenhandbuch_geometriegroessen_000.svg?nolink&700 |}}
  
 **Figure:** Modular setup of both screw and barre **Figure:** Modular setup of both screw and barre
Zeile 244: Zeile 244:
 with: with:
  
-$$A_{ABC} = \frac{\Omega}{4} \cdot a^2\tag{27}$$+$$A_{ABC} = \frac{\Omega}{4} \cdot a^2 \tag{27}$$
  
-$$A_{MB/C} = \left[\Omega + \frac{\pi}{2} - \alpha - \arcsin\left(\frac{R_a}{R_i} \cdot \cos(\alpha)\right)\right] \cdot \frac{R_i^2}{2}\tag{28}$$+$$A_{MB'C} = \left[\Omega + \frac{\pi}{2} - \alpha - \arcsin\left(\frac{R_a}{R_i} \cdot \cos(\alpha)\right)\right] \cdot \frac{R_i^2}{2} \tag{28}$$
  
-$$A_{MB/C/} = \frac{1}{2}\left\{\frac{a \cdot \sin(\Omega/2)}{\cos(\alpha \Omega)} \frac{R_i \cdot \cos\left[\alpha + \arcsin\left(\frac{R_a}{R_i} \cdot \cos(\alpha)\right)\right]}{\cos(\alpha)}\right\} \cdot R_a \cdot \cos(\alpha)\tag{29}$$ +$$A_{MB'C'} = \frac{1}{2}\left\{a \cdot \sin(\Omega/2) + R_i \cdot \cos\left[\alpha + \arcsin\left(\frac{R_a}{R_i} \cdot \cos(\alpha)\right)\right]\right\\cdot \frac{r - R_i \cdot \cos\left(\Omega + \phi + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right]\right)}{\cos(\alpha - \Omega)} R_a \cdot \cos(\alpha) \tag{29}$$
  
-$$A_{ABC/} = \frac{1}{2} \cdot \frac{a \cdot \sin(\Omega/2)}{\cos(\alpha - \Omega)} \cdot a \cdot \cos(-\alpha + \Omega/2)\tag{30}$$+$$A_{ABC'} = \frac{1}{2} \frac{a \cdot \sin(\Omega/2)}{\cos(\alpha - \Omega)} \cdot a \cdot \cos(-\alpha + \Omega/2) \tag{30}$$
  
-$$A_{ABC} = \frac{\Omega}{4} \cdot a^2 \tag{31}$$ +$$A_{B'B'B''} = \frac{1}{2}r^2 \sqrt{1 - \frac{\left[r - R_i \cdot \cos\left\{\Omega + \phi + \arcsin\left(\frac{R_a}{R_i} \cos(\alpha)\right)\right\}\right]^2}{(R_i + r)^2}}$$
- +
-$$A_{MB'C} = \left[\Omega + \frac{\pi}{2} - \alpha - \arcsin\left(\frac{R_a}{R_i} \cdot \cos(\alpha)\right)\right] \cdot \frac{R_i^2}{2} \tag{32}$$ +
- +
-$$A_{MB'C'} = \frac{1}{2}\left\{a \cdot \sin(\Omega/2) + R_i \cdot \cos\left[\alpha + \arcsin\left(\frac{R_a}{R_i} \cdot \cos(\alpha)\right)\right]\right\} \cdot \frac{r - R_i \cdot \cos\left(\Omega + \phi + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right]\right)}{\cos(\alpha - \Omega)} + R_a \cdot \cos(\alpha) \tag{33}$$ +
- +
-$$A_{ABC'} = \frac{1}{2} \frac{a \cdot \sin(\Omega/2)}{\cos(\alpha - \Omega)} \cdot a \cdot \cos(-\alpha + \Omega/2) \tag{34}$$ +
- +
-$$A_{B'B'B''} = \frac{1}{2}r^2 \sqrt{1 - \frac{\left[r - R_i \cdot \cos\left\{\Omega + \phi + \arcsin\left(\frac{R_a}{R_i} \cos(\alpha)\right)\right\}\right]^2}{(R_i + r)^2}} \tag{35}$$+
  
 $$- \frac{1}{2}R_i^2 \sin\left\{-\Omega - \phi - \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right] - \arccos \frac{r - R_i \cdot \cos\left(\Omega + \phi + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right]\right)}{R_i + r}\right\} +$$ $$- \frac{1}{2}R_i^2 \sin\left\{-\Omega - \phi - \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right] - \arccos \frac{r - R_i \cdot \cos\left(\Omega + \phi + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right]\right)}{R_i + r}\right\} +$$
Zeile 270: Zeile 262:
 $$- \frac{1}{2}r^2 \arccos \frac{r - R_i \cdot \cos(\phi + \Omega + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right])}{R_i + r}$$ $$- \frac{1}{2}r^2 \arccos \frac{r - R_i \cdot \cos(\phi + \Omega + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right])}{R_i + r}$$
  
-$$- \frac{1}{2}R_i^2 \left(-\phi - \Omega + \pi - \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right] - \arccos \frac{r - R_i \cdot \cos(\phi + \Omega + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right])}{R_i + r}\right)$$+$$- \frac{1}{2}R_i^2 \left(-\phi - \Omega + \pi - \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right] - \arccos \frac{r - R_i \cdot \cos(\phi + \Omega + \arcsin\left[\frac{R_a}{R_i} \cos(\alpha)\right])}{R_i + r}\right)\tag{31}$$ 
 Since the maximum channel depths of both the pushing flight element and the traditional conveying element are identical, we can calculate the average channel depth using the following equation: Since the maximum channel depths of both the pushing flight element and the traditional conveying element are identical, we can calculate the average channel depth using the following equation:
  
-$$\bar{h} = \frac{A_{free}}{b_{max}}\tag{9}$$+$$\bar{h} = \frac{A_{free}}{b_{max}}\tag{32}$$
  
 ==== Intermeshing Region of the Two Screws ==== ==== Intermeshing Region of the Two Screws ====
Zeile 285: Zeile 278:
 This area can be calculated according to Booy  [[en:grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders#references|[Boo78]]] using the following equation: This area can be calculated according to Booy  [[en:grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders#references|[Boo78]]] using the following equation:
  
-$$A_{zw} = \left(\frac{D_s}{2}\right)^2 \cdot \sin(\Omega) - \frac{A_{Fr}}{i} \cdot \left(1 - \frac{\phi \cdot i}{\pi}\right)\tag{10}$$+$$A_{zw} = \left(\frac{D_s}{2}\right)^2 \cdot \sin(\Omega) - \frac{A_{Fr}}{i} \cdot \left(1 - \frac{\phi \cdot i}{\pi}\right)\tag{33}$$
  
 ==== Shouldered Kneading Blocks ==== ==== Shouldered Kneading Blocks ====
Zeile 295: 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 303: 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.
  
-$$h_{groove} = 0.5 \cdot \left(\frac{\bar{h}}{\frac{1}{4} \cdot \pi - \Phi} \cdot \alpha - \frac{\Phi \cdot \bar{h}}{\frac{1}{4} \cdot \pi - \Phi} + s_R\right)\tag{13}$$+$$h_{groove} = 0.5 \cdot \left(\frac{\bar{h}}{\frac{1}{4} \cdot \pi - \Phi} \cdot \alpha - \frac{\Phi \cdot \bar{h}}{\frac{1}{4} \cdot \pi - \Phi} + s_R\right)\tag{36}$$
  
 {{ :en:grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders:en_sigma150_dlg_grundlagenhandbuch_geometriegroessen_016.svg?600%nolink |}} {{ :en:grundlagenhandbuch:geometriegroessen_des_gleichdrall-doppelschneckenextruders:en_sigma150_dlg_grundlagenhandbuch_geometriegroessen_016.svg?600%nolink |}}
Zeile 311: 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 321: 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 337: 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 $e$
  
-$$e = \frac{D_{a,3} - D_{i,3}}{2} \tag{Equation 3-15}$$+$$e = \frac{D_{a,3} - D_{i,3}}{2} \tag{42}$$
  
 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 359: 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: $$\angle AOB = \angle BOC = \angle COD = \Omega_3 = 60° \tag{44}$$
  
-Flank angle: $\phi_{k,3} = \phi_{g,3} = 0 \tag{Equation 3-18}$ +Flank angle: $$\phi_{k,3} = \phi_{g,3} = 0 \tag{45}$
  
-Outside radius: $R_{a,3} = \frac{D_{a,3}}{2} \tag{Equation 3-19}$+Outside radius: $$R_{a,3} = \frac{D_{a,3}}{2} \tag{46}$$
  
-Inside radius: $R_{i,3} = \frac{D_{i,3}}{2} = \left(a - \frac{D_{a,3}}{2}\right) \tag{Equation 3-20}$ +Inside radius: $$R_{i,3} = \frac{D_{i,3}}{2} = \left(a - \frac{D_{a,3}}{2}\right) \tag{47}$
  
 The coordinates of the points in the three-course standard profile can be calculated by these geometry sizes. Because the profile is symmetrical, only half the contour is selected as the calculation object. The coordinates of the points in the three-course standard profile can be calculated by these geometry sizes. Because the profile is symmetrical, only half the contour is selected as the calculation object.
  
-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,3}$$y_B = R_{a,3} \cdot \sin 60° = \frac{\sqrt{3}}{2}R_{a,3}$+B: $x_B = R_{a,3} \cdot \cos 60° = \frac{1}{2}R_{a,3}; y_B = R_{a,3} \cdot \sin 60° = \frac{\sqrt{3}}{2}R_{a,3}\tag{49}$
  
-C: $x_C = R_{i,3} \cdot \cos 120° = -\frac{1}{2}R_{i,3}$$y_C = R_{i,3} \cdot \sin 120° = \frac{\sqrt{3}}{2}R_{i,3}$+C: $x_C = R_{i,3} \cdot \cos 120° = -\frac{1}{2}R_{i,3}; y_C = R_{i,3} \cdot \sin 120° = \frac{\sqrt{3}}{2}R_{i,3}\tag{50}$
  
-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 393: 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 422: Zeile 415:
 These sections are characterized by the following dimensionless numbers: These sections are characterized by the following dimensionless numbers:
  
-$$k_1 = \frac{D_a}{D_z}\tag{23}$$ +$$k_1 = \frac{D_a}{D_z}\tag{54}$$ 
  
-$$k_2 = \frac{D_i}{D_a}\tag{24}$$+$$k_2 = \frac{D_i}{D_a}\tag{55}$$
  
-$$cl = \frac{a}{D_z/2}\tag{25}$$ +$$cl = \frac{a}{D_z/2}\tag{56}$$ 
  
 ==== Thoothed Mixing Elements ==== ==== Thoothed Mixing Elements ====