Square edge

Orifice Meters A square-edged or sliarp-edged orifice, as shown in Fig. 10-18, is a clean-cut square-edged hole with straight walls perpendicular to the flat upstream face of a thin plate placed crosswise of the channel. The stream issuing from such an orifice... 

FIG. 10-18 Square -edged or sharp-edged orifices. The plate at the orifice opening must not be thicker than one-thirtieth of the pipe diameter, one-eighth of the orifice diameter, or one-fourth of the distance from the pipe wall to the edge of the opening, (a ) Pipe-line orifice, (h ) Types of plates. 

FIG. 10-19 Coefficient of discharge for square-edged circular orifices for Nrs > 30,000 with the upstream tap located between one and two pipe diameters from the orifice plate [Spitzglass, Trans. Am. Soc. Mech. Eng., 44, 919 (1922).]... 

FIG. 10-20 Coefficient of discharge for square-edged circular orifices with comer taps. [Tuve and Sprenkle, Instruments, 6, 201 (J.933),]... 

Accuracy Square-edged orifices and venturi tubes have been so extensively studied and standardized that reproducibihties within 1 to 2 percent can be expected between standard meters when new and clean. This is therefore the order of reliabihty to be had, if one assumes (1) accurate measurement of meter differenfial, (2) selection of the coefficient of discharge from recommended published literature, (3) accurate knowledge of fluid density, (4) accurate measurement of critical meter dimensions, (5) smooth upstream face of orifice, and (6) proper location of the meter with respect to other flow-disturbing elements in the system. Care must also be taken to avoid even sh t corrosion or fouliug during use. 

Gas-Solid Mixtures Carlson, Frazier, and Engdahl [Trans. Am. Soc. Mech. Eng., 70, 65-79 (1948)] describe the use of a flow nozzle and a square-edged orifice in series for the measurement of both the gas rate and the solids rate in the flow of a finely divided solid-in-gas mixture. The nozzle differential is sensitive to the flow of both phases, whereas the orifice differential is not influenced by the sohds flow. 

As core and facesheet surface preparation became more environmentally durable, the need to fully enclose the core waned. The open square-edge de-... 

Fig. 31. Square-edge sandwich design. Reproduced by permission of the Boeing Company.

Square-edge stiffened panels are used extensively on current production aircraft such as the 737,757 and 767, primarily in the aft fuselage (unpressurized section). 

Fig. 32. Empennage leading edge. square-edge panel. Reproduced by peniiission of the Boeing Company.

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.

Coefficient entry or discharge) The ratio of aerodynamic (effective) area to the measured area of an opening. The value for a square-edged hole of 0.61 is used for most building openings. 

BE-ENTRANT tube SNARP- 306 ED SQUARE EDGED PE-ENTRANT TUBE SQUARE EDGED WELL BOUNDED... 

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

Square-edge orifice coefficients, calculation of, 11 659 Square planar... 

Coefficient C for a square-edged eccentric circular orifice (with opening tangent to pipe wall) varies from about 0.61 to 0.63 for [3 s from 0.3 to 0.5, respectively, and pipe Reynolds numbers > 10,000 for either vena-... 

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