Conveying angle

Campbell et al. and Yamamuro et al. assume a form for (or F ) and then determine the solids conveying angle (p. Hyun and Spalding calculated q> using a force balance and two torque balances. Campbell and Dontula and Yamamuro et al. did not use a torque balance in their analysis. The following is a list of assumptions from all the models discussed. Additional assumptions will be added as needed. Assumptions that do not have keys were used by all authors ... 

The sohds conveying angle 0 is zero for stationary solids (u = 0) and increases with increasing flow rate or throughput (increasing u). Neglecting the impact of cross-channel modification in friction, a force balance on the plug allows us to determine a relation akin to Eq. (21-135) for compaction in a channel, or... 

FIG. 21-145 The unwound screw channel, illustrating the barrel moving at a velocity V and at a angle 6 with respect to the down channel direction x. The barrel slides over the solids at a relative velocity V, resulting in a frictional shear stress along the wall of and a solids conveying angle of 0. 

If curvature is taken into account the expression for the solids conveying angle can be written as ... 

Figure 7.11 Solids conveying angle vs. channel depth calculated with Eqs. 7.52 and 7.53...

This is the case when the helix angle on the barrel cp equals the solids conveying angle of the solid bed in the screw channel 0s. Thus, the effective velocity difference and the frictional heat generation is minimized when ... 

This angle 0 is essentially the same angle as the solids conveying angle discussed in Section 7.2.2. If the polymer melt behaves as a Newtonian fluid, Eq. 7.87 becomes ... 

Eq. 12.1 shows us that in order to be able to estimate the solids conveying rate we must be able to calculate 6 the solids conveying angle. 

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