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Fluid Mechanics
Published in P.K. Jayasree, K Balan, V Rani, Practical Civil Engineering, 2021
P.K. Jayasree, K Balan, V Rani
The orifice meter (Figure 12.27) consists of a flat orifice plate with a circular hole drilled in it. There is a pressure tap upstream from the orifice plate and another just downstream. There are three recognized methods of placing the taps. The coefficient of the meter will depend upon the position of taps. The principle of the orifice meter is identical with that of the venturimeter. The reduction of the cross section of the flowing stream in passing through the orifice increases the velocity head at the expense of the pressure head, and the reduction in pressure between the taps is measured by a manometer. Bernoulli’s equation provides a basis for correlating the increase in velocity head with the decrease in pressure head.
Orifices
Published in Béla G. Lipták, Flow Measurement, 2020
W. H. Howe, J. B. Arant, B. G. Lipták, S. Rudbäck
Head-type flow measurement derives from Bernoulli’s Theorem which states that in a flowing stream, the sum of the pressure head, the velocity head, and the elevation head at one point is equal to their sum at another point in the direction of flow plus the loss due to friction between the two points. Velocity head is defined as the vertical distance through which a liquid would fall to attain a given velocity. Pressure head is the vertical distance which a column of the flowing liquid would rise in an open-ended tube as a result of the static pressure.
Processing Principles
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
Pressure head is important primarily in the pumping of liquids. It is computed using ΔPH=m(P2−P1)ρ
Protection of river downstream of hydropower plant
Published in Journal of Applied Water Engineering and Research, 2019
Narimantas Titas Ždankus, Saulius Vaikasas, Gintautas Sabas
Flow rate Q is expressed as the product of flow velocity v and cross-sectional area A. Hydrodynamic head H is expressed as the sum of elevation z, pressure head p/(ρg) and velocity head v2/(2g). The sum of elevation and pressure head characterises potential energy, while the velocity head characterizes kinetic energy of the flow. For open water flow of river, the sum of elevation and pressure head equals to depth of the flow h. Thus, hydrodynamic head may now be expressed in the form: