What is the coefficient of orifice meter?
�Orifice coefficient, generally, is 0.61 in case of flange taps and vena-contracta taps for NRe< 30,000. �In the process of calculating fluid velocity with a orifice meter, the velocity of approach is not included.
What is coefficient of contraction orifice?
The coefficient of contraction is defined as the ratio between the area of the jet at the vena contracta and the area of the orifice. The typical value may be taken as 0.611 for a sharp orifice (concentric with the flow channel). The smaller the value, the more effect the vena contracta has.
What is the working principle of orifice meter?
Basic Working Principle of an Orifice Meter The liquid or gas whose flow rate is to be determined is passed through the orifice plate. This creates a pressure drop across the orifice plate which varies with the flow rate, resulting in a differential pressure between the outlet and inlet segments.
Can coefficient of discharge be greater than 1?
In practice, the discharge coefficient cannot be greater than one. This is a fact. The error may be in compensating the values of the variables in the equation. Verifies units, values, and homogeneity of area values.
Why coefficient of discharge is calculated?
The discharge coefficient is the actual flow ratio with the theoretical flow and makes allowances for flow contractions and friction effects. The discharge coefficient is a function of the Reynolds number while the Reynolds number is a function of the flow rate calculated using the discharge coefficient value.
Can the coefficient of contraction be greater than 1?
Plug in a coefficient for energy losses through turbulence and you have your formula. But you can see indeed that your coefficient can never be greater than one, because that would mean that you end up with more energy than you started with.
What is a coefficient of contraction?
physics. : the ratio of the cross-sectional area of the first vena contracta to the area of the discharge aperture.
Can the coefficient of discharge be greater than 1?
How to calculate the orifice flow meter discharge coefficient?
The equation gives flow rate, Q, in terms of the measured pressure difference, P 1 – P 2, the density of the fluid, ρ, the ratio of orifice diameter to pipe diameter, β, the cross-sectional area of the orifice, A o, and the orifice discharge coefficient, C d.
When did the orifice flow meter come out?
ISO 5167, which came out in 1991, set three standard configurations for the pressure taps in an orifice flow meter. It also provided means to calculate the orifice discharge coefficient for any ratio of orifice diameter to pipe diameter if one of the standard pressure tap configurations is used.
Why is ISO 5167 used for orifice meter?
This provided greater flexibility for orifice meters, because orifice plates with different orifice diameters could be used in a given orifice meter, while still allowing accurate determination of the orifice discharge coefficient.
Which is better the orifice meter or the venturi meter?
High pressure and energy recovery makes the venturi meter suitable where only small pressure heads are available. A discharge coefficient cd = 0.975 can be indicated as standard, but the value varies noticeably at low values of the Reynolds number. The pressure recovery is much better for the venturi meter than for the orifice plate.