Orifice plate flow rate calculator

flow rate measurement calculator

online since 2005

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Calculation setup
Pressures
Flow rates and velocities
Orifice dimensions and coefficients
Fluid properties

Calculator description

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Also, read about calculation procedures, what you have to know for the calculations and what limitations apply.

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Issues and answers

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issues and answers

Description

p1 - pressure on the inlet
Absolute pressure in front of the orifice
p2 - pressure on the outlet
Absolute pressure after the orifice
Δp - pressure drop
Pressure difference between pipe start and pipe end
Δω - pressure loss
That can't be recovered after the orifice
D1 - diameter of tube
Internal pipe diameter
D2 - orifice diameter
Diameter of orifice
e - expansion factor
Coefficient used for compressible flow calculation
C - coefficient of discharge
Coefficient used for orifice plate based on ISO 5167
ReD - upstream Reynolds number
Reynolds number calculated in front of the orifice
K - resistance coefficient
That you can use in pipeline calculation, as orifice is creating local pressure losses in the pipeline
q1 - volumetric flow rate
Fluid flow rate in terms of units of volume per unit of time on the inlet conditions
q - standard flow
Flow rate at standard conditions. Used only if the selected fluid is gas.
ṁ - mass flow rate
Fluid flow rate in terms of units of mass per unit of time
V1 - upstream velocity
Flow velocity in front of the orifice where flow diameter is D1
T1 - upstream temperature
Fluid temperature for gas density calculation based on the ideal gas state equation
ρ1 - upstream density
Fluid density in the front of orifice in terms of mass per unit of volume
R - gas constant
Gas constant in terms of energy per unit of mass and temperature, for gas density calculation using ideal gas state equation
κ - isentropic coefficient
Specific heat ratio
ν - kinematic viscosity
Result of fluid particles colliding to each other and moving at different velocities in terms of area per square unit of time
μ - dynamic viscosity
Result of fluid particles colliding to each other and moving at different velocities in terms of mass per square unit of distance and time

Calculation setup

Select orifice type based on the measuring taps placement
Corner taps
When measuring taps are placed in the orifice corners
Flange taps
When measuring taps are placed in the orifice flanges
D - D/2
When measuring taps are placed in front and after the orifice on given distance
Select value to input. You should enter selected one. The other one will be calculated
p2
pressure downstream from the orifice
Δp
measured pressure difference in front and after the orifice
Select value to input. You should enter selected one. The other one will be calculated
ν
kinematic viscosity
μ
dynamic viscosity
Select value to input. Available only if gas is selected. You should enter selected one. The other one will be calculated
T1
upstream temperature.
ρ1
upstream density.
Select fluid type
Gas
for compressible flow where ideal gas state equation is applicable
Liquid
for incompressible flow of liquids
Application of ISO 5167 constraints
ISO constraints
Deselect if you don't want to check if the orifice and the flow conditions are within the limits of the ISO standard.

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