Orifices and Nozzles

Gas impingement from slots, orifices, and nozzles at 10—100 m/s velocities is used for drying sheets, films, coatings (qv), and thin slabs, and as a secondary heat source on dmm dryers and paper (qv) machine cans. The general relationship for convection heat transfer is (13,14) ... 

TABLE 10-5 Locations of Orifices and Nozzles Relative to Pipe Fittings... 

P = ratio of small to large diameter orifices and nozzles and contractions or enlargements in pipes... 

For estimating purposes for liquid flow with tiscosity similar to water through orifices and nozzles, the following can be used [53] ... 

Figure 2-38C. Critical Pressure Ratio, r, for compressible flow through nozzles and venturi tubes. By permission, Crane Co., Technical Paper 410, 1957. Also see 1976 edition. See note at Figure 2-18 explaining details of data source for chart. Note P = psia p= ratio of small-to-large diameter in orifices and nozzles, and contractions or enlargements in pipes.

Flow coefficient for orifices and nozzles which equal the discharge coefficient corrected for velocity of approach = C / (1 - p" )V2... 

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

In this chapter consideration is given to the flow of gases through orifices and nozzles, and to flow in pipelines. It is found that, in all these cases, the flow may reach a limiting maximum value which is independent of the downstream pressure this is a phenomenon which does not arise with incompressible fluids. 

Among the devices used for the measurement of discharge are orifices and nozzles. Tubes are rarely so used but are included here because their theory is the same, and experiments upon tubes provide information as to entrance losses from reservoirs into pipelines. 

FIGURE 5.23 Expansion factor for square-edged orifice and nozzle or venturi meter (a) k= 1.3, (b) k= 1.4. (From Crane Co., Flow of Fluids through Valves, Fittings, and Pipe, Technical Manual 410, Crane Co., New York (1978).)... 

It may be a large dial micrometer with alarm setting for an axial movement of 0.4 millimeter and shutdown at 0.8 millimeter, or An oil pressure gauge connected to an oil leak-off device may also be used as an axial position indicator. The oil is supplied at say 500 kPa, flows through an orifice and leaks off through a nozzle. The pressure between the orifice and nozzle depends on the distance between the nozzle and shaft thrust collar the larger the distance the lower the... 

Orifices and nozzles, which bring about mixing and dispersion by causing a high degree of turbulence in the stream of the flowing liquids. 

This coefficient is not dimensionally homogeneous and is not equal to the discharge coefficient from orifices and nozzles. Although the flow coefficient was developed for control valves, a relationship is often established for other fittings in terms of the Tiffactor ... 

Lakshmana Rao, N.S. Shridharan, K. 1972. Orifice losses for laminar approach flow. ASCE Journal of Hydraulics Division, Vol.98, No.ll, (November), pp. 2015-2034 Lakshmana Rao, N.S., Srhidharan, K. Alvi, S.H. (1977). Critical Reynolds Number for orifice and nozzle flows in pipes. Journal of Hydraulic Research, International Association for Hydraulic Research, Vol. 15, No. 2, pp. 167-178 Ma, T. W. (1987). Stability, rheology and flaw in pipes, fittings and venturi meters of concentrated non-Newtonian suspensions. Unpublished PhD thesis. University of Illinois, Chicago... 

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