Flow through curved conduit

Fluid Flow Through Rough Horizontal Conduit, 381 Fluid Flow Through Curved Conduit, 384... 

The flow through a helical coil is uniquely different from that through a straight pipe due to the secondary flow pattern induced by the imbalance in the radial direction between the outwards-directed centrifugal force and the inwards-directed pressure force acting on the fluid. Reviews by Berger et al. [34], Nandakumar and Masliyah [36], and Ito [40] summarize recent studies of curve pipe flows. Ali reported the pressure drop performance of different types of coiled tubes [41]. The literature review attempted here is not broad or deep, but focuses mainly on the pressure drop of fluid flow through horizontal conduits and curved pipes. 

We usually want to determine the total flow rate (Q) through the conduit rather than the velocity at a point. This can be done by using Eq. (10-1) or Eq. (10-2) if the local velocity is measured at a sufficient number of radial points across the conduit to enable accurate evaluation of the integral. For example, the integral in Eq. (10-2) could be evaluated by plotting the measured v(r) values as v(r) vs. r2, or as rv(r) vs. r [in accordance with either the first or second form of Eq. (10-2), respectively], and the area under the curve from r = 0 to r = R could be determined numerically. 

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