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Terms used inflow measurement

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Field Instrumentation

Terms used inflow measurement
Density
It is defined as mass of a unit volume of that fluid. Its units are g/cm3, Kg/m3, g/l.
Relative density (Specific gravity)
It is ratio of two densities. It is the ratio between the density of a certain liquid and the density of water or it is the ratio between the density of a certain gas and the density of air. It is a unitless number.
Compressibility
It is the ability of a substance to decrease in volume when pressure is applied.
Viscosity Viscosity of a fluid is defined as its resistance to flow. It is affected by the temperature. In metric system its unit is poise (1 dyne-s/cm2); while in English system its unit is lb-s/ft2.
Laminar flow
It is a smooth, layered flow. Laminar flow pattern in a pipe looks like the concentric rings. The flow lines are called streamlines. An object that disrupts the flow pattern only slightly is said to be streamlined.
Turbulent flow
It is rough and irregular. It is made up of many small currents, swirling and weaving in all direction, forming miniature whirlpools called eddy currents. It causes considerable frictional resistance to fluid flow. An object placed inflow path creating turbulence is called blunt object.
Bernoulli Effect
It states that as the fluid velocity increases, the pressure on the walls decreases. This inverse relationship between fluid velocity and the pressure of containments is called Bernoulli Effect. It can be expressed as,
V= K (ΔP/D) The square root relationship between the flow velocity and the pressure differential causes a nonlinear output in many flow meters. Head pressure of any liquid is calculated by, P = DH

53 Field Instrumentation GEN Rev) The liquid’s weight density in lb/ft3 divided by 144 in gives pressure in psi at bottom of a cubic foot of that liquid.

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