Velocity correction factor

Step 6 Note the velocity given by this line as 16.5 ft/s, then proceed to the insert on the right, and read upward from 600 psig to 200 psig to find the velocity correction factor as 0.41. 

OL velocity correction factor (unitless) or thermal diffusivity (area/time)... 

Wadell (Wl, W2) proposed that the sphericity ij/, defined in Chapter 2, could be used to correlate drag on irregular particles. The appropriate dimension for definition of Re and is then the diameter of the sphere with the same volume as the particle. Figure 6.14 shows velocity correction factors calculated on this basis (G5). This approach has found widespread acceptance, although there is experimental evidence that terminal velocity does not correlate well with sphericity (B8, S8). 

Heywood gave drag curves for various values of k (H3), and tabulated the velocity correction factor (H2). Figure 6.15 shows plotted from Heywood s table. There is empirical evidence for the validity of this approach (Dl). As with sphericity, comparison for specific shapes is informative. For oblate spheroids (for which Ja is the equatorial diameter) and Re < 100,... 

Fig. 9.5 Terminal Reynolds number and velocity correction factor for rigid spheres on the axis of circular ducts.

Here is the interfacial-velocity correction factor for kxi- We recommend the film model... 

To assess the physical deviation between the average of products and the product of averages a momentum velocity correction factor can be defined by Cm = vz) / v1)a- By use of the Hagen-Poiseuille law (1.353) and the power law velocity profile (1.354) it follows that at steady state Cm has a value of about 0.95 for turbulent flow and 0.75 for laminar flow [55]. In practice a value of 1 is used in turbulent flow so that v1)a is simply replaced by the averaged bulk velocity vz) - On the other hand, for laminar flows a correction factor is needed. For more precise calculations a simplified (not averaged ) 2D model is often considered for ideal axisymmetric pipe flows [52, 69]. 

Again, to assess the physical deviation between the average of products and the product of averages a kinetic-energy velocity correction factor can be defined by a/ vz) - By use of the Hagen-Poiseuille law... 

The term (i )j /(2i , ) can be replaced by viJli, where a is the kinetic-energy velocity correction factor and is equal to ilJ(v ), . The term a has been evaluated for various flows in pipes and is y for laminar flow and close to 1.0 for turbulent flow. (See Section 2-7D.) Hence, Eq. (2.7-9) becomes... 

EXAMPLE 2.8-1. Momentum Velocity Correction Factor p for Laminar Flow... 

The momentum velocity correction factor P is defined as follows for flow in one direction where the subscript x is dropped. 

Kinetic-Energy Velocity Correction Factor for Turbulent Flow. Derive the equa-... 

Recurrence coefficient for the family of Jacobi polynomials Kinetic-energy velocity correction factor (—)... 

Dukler no slip liquid volume fiiaction, see Eq. (15a). vapor superficial velocity correction factor see Eq. (13). liquid superficial velocity correction factor see Eq. (14), a dimensionless corielatbg factor, see Eq. (16b). 

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