Steady Drag-induced Flow in Straight Channels

9 STEADY DRAG-INDUCED FLOW IN STRAIGHT CHANNELS 

Next we can proceed with the force balance on the differential element shown in Fig. 4.16. We first concentrate on making a down-channel force balance, neglecting the cross-channel component of the forces 

Hence the ratio of forces, which by dividing by the cross-sectional area also equals the ratio of axial stresses, which we shall refer to as pressures, become a function of the flow rate via the angle 4 determined by Eq. 4.9-1. This implies that, for a given inlet pressure P0, a fixed outlet pressure determines the flow rate, or conversely, a given flow rate determines the magnitude of outlet pressure the device can generate. The lower the flow rate, the higher the pressure rise. 

The previously described solids conveying mechanism represents, in essence, the conveying of solids in SSEs, although a realistic conveying model for the latter is somewhat more complicated because, as Chapter 9 explains, the channel is curved. 

Drag-induced flow in a rectangular channel, as in Fig. 4.15, neglecting cross-channel forces, resulted in Eq. 4.9-3. We now consider the effect of these forces on the conveying mechanism. 

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Steady Drag-induced Flow in Straight Channels, 162... 

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