Couette striation thickness

Predicting the Striation Thickness in a Couette Flow System — Shear Thinning Model... 

Figure 6.48 Striation thickness reduction as a function of number of revolutions in a Couette device.

FIGURE 6.11 Effect of shear strain on striation thickness of particles of the minor component represented by simple geometries, in a plane Couette flow (PCF). 

Example 6.7. Striation Thickness in Rotational Couette Flow (RCF)... 

Consider a rotational Couette geometry with the inside cylinder rotating, as shown in Figure 6.13a, and with the minor component represented by a black line. The position of the black line at time t = 0 shows the feedport of the system. After the inner cylinder starts rotating, the black line transforms into a spiral. Calculate the striation thickness as a function of the total number of revolutions of the inner cylinder and the geometry of the system. 

FIGURE 6.14 Striation thickness reduction function in rotational Couette flow (RCF) for various ratios of the outside to the inside radius. Newtonian and power-law fluids do not exhibit any significant difference. 

We finally return to the solution of Design Problem V (Fig. 6.31). The flow in the die is helical in nature that is, it consists of an axial PoiseuiUe flow and a drag Couette rotational flow due to the rotation of the mandrel. The analysis of the striation thickness of each layer will be based on simple geometrical and kinematical arguments, and it will be shown that the two approaches give the same results. For Newtonian fluids, the axial and angular flow fields are independent and given in Tables 2.7 and Example 6.7, respectively. 

A.12 Rotational Couette Flow for a Power-Law Fluid. Prove that, for a rotational Couette geometry with the inside cylinder rotating, the striation thickness scales inversely proportional to the shear... 

B.7 Striation Thickness in RCF with Both Cylinders Rotating. A power-law fluid is sheared in a rotational Couette geometry with both cylinders rotating. Prove that the ratio of the striation thickness reduction of this case to the case described in Example 6.7 (only inside cylinder rotating) is equal to (A. -p 1) , where A is the ratio of the angular velocities of the inside cylinder to the outside cylinder. 

B.8 Striation Thickness in Axial Annular Couette Geometry. Calculate the striation thickness reduction function for flow in axial annular Couette geometry and for a power-law fluid. 

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