Discharge coefficients for

The discharge coefficient for the screen C with aperture D, is given as a function of screen R nolds number Re = D,(V/d) /[L in Fig. 6-16 for plain square-mesfi screens, Ot = 0.14 to 0.79. This cui ve fits most of the data within 20 percent. In the laminar flow region, Re < 20, the discharge coefficient can be computed from... 

Discharge coefficients for critical flow nozzles are, in general, the same as those for subsonic nozzles. See Grace and Lapple, Trans. Am. Soc. Mech. Fug., 73, 639-647 (1951) and Szaniszlo, ]. Eug. Power, 97, 521-526 (1975). Arnberg, Britton, and Seidl [J. Fluids Eug., 96, 111-123 (1974)] present discharge-coefficient correlations for circular-arc venturi meters at critical flow. For the calciilation of the flow of natural gas through nozzles under critical-flow conditions, see Johnson,/. Ba.sic Eng., 92, 580-589 (1970). 

Measurements by Harris and MagnaU [Trans. Jn.st. Chem. Eng. (London), 50, 61-68 (1972)] with a venturi (p = 0.62) and orifices wiSi radius taps (P = 0.60-0.75) indicate that the discharge coefficient for nonnewtonian fluids, in the range Nr (generalized Reynolds number) 3500 to 100,000, is approximately the same as for newtonian fluids at the same Reynolds number. 

FIG. 14-30 Discharge coefficients for gas flow, sieve plates. [Liebson, Kelley, and Bullington, Pet. Refiner, 36(3), 288 (1957).]... 

Cj = discharge coefficient for nozzles and orifices hL = differential static head or pres.sure loss across... 

Figure 2-18. Flow coefficient C for square edged orifices. By permission, Crane Co. [3], Technical Paper 410 Engineering Div. (1976) and Fluid Meters, Their Theory and Application Part 1, 6th Ed., 1971, American Society of Mechanical Engineers and, Tuve, G. L. and Sprenkle, R. E., Orifice Discharge Coefficients for Viscous Liquids, Instruments Nov. 1933, p. 201.

Figure 2-39. Discharge coefficients for liquid flow. By permission, Cameron Hydraulic Data, Ingersoll-Rand Co., Washington, N.J., 1979.

Discharge coefficient for orifice and nozzles Diameter correction factor, vacuum flow. Figure 2-43 Diameter correction factor, v acuum flow. Figure 2-4.3... 

Cq = discharge coefficient for sharp-edged orifice = 0.61 for Reynolds Number > 30,000 and not sonic... 

At = total tower cross-sections, area, ft-Cq = vapor discharge coefficient for dry tray g = acceleration of gratdty, 32.2 ft/sec hj, = head loss due to vapor flow through perforations, in. liquid... 

Figure 8-129. Discharge coefficients for vapor flow, sieve trays. Used by permission, Smith, B. O., Design of Equilibrium Stage Processes, Chapter 15, by J. R. Fair, McGraw-Hill Book Co. (1963) data from I. Liebson, R. E. Kelley, and L. A. Bullington, Petroleum Refiner, V. 36 (2), Feb. (1957) p. 127 V. 36 (3), (1957) pg. 288, all rights reserved.

In subcritical flow the discharge coefficient is affected by the velocity of approach as well as the type of choke and the ratio of choke diameter to pipe diameter. Discharge coefficients for subcritical flow are given in Figure 2-24 as a function of the diameter ratio and the upstream Reynolds number. Since the flow rate is not initially known, it is expedient to assume C = 1, calculate Q, use this Q to calculate the Reynold s number, and then use the charts to find a better value of C. This cycle should be repeated until the value of C no longer changes. 

According to Miller (1983), for NReo > 4000 the discharge coefficient for the venturi, as well as for the nozzle and orifice, can be described as a function of NReD and fi by the general equation... 

Figure 10-8 Orifice discharge coefficient for square-edged orifice and flange, corner, or radius type (From Miller, 1983.)...

Cg control valve discharge coefficient for gas flow, L4tT1,2/M]... 

More details on discharge coefficients for these types of liquid discharges are provided elsewhere.3... 

Equations are also available for orifices7 and for changes in pipe sizes.8 The 2-K method also represents liquid discharge through holes. From the 2-K method an expression for the discharge coefficient for liquid discharge through a hole can be determined. The result is... 

The simplified ERM is very convenient in that all the properties can be evaluated at the stagnation conditions in the reactor. The method may be appropriate for relief sizing for vapour pressure systems when flow is to be via a safety valve. Discharge coefficients for two-phase flow through safety valves are discussed in 9.7.1. -... 

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