@wikipedia
A ratio between compressible fluid volumetric flowrate and incompressible fluid volumetric flowrate through the ideal orifice:
| LaTeX Math Block |
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\epsilon = \frac{q_{\rm compressible}}{q_{\rm incompressible}} |
where
| LaTeX Math Block |
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| anchor | q_ideal |
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| alignment | left |
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q_{\rm incompressible} = \frac{\pi d^2}{4} \cdot \sqrt{\frac{2 \cdot \Delta p}{\rho \cdot (1-\beta^4)}} |
and
| pressure drop on the choke, | LaTeX Math Inline |
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| body | \Delta p = p_{in} - p_{out} |
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|
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| orifice narrowing ratio |
| orifice diameter |
| pipe diameter |
For incompressible fluids (water and most types of oil) the expansion factor is
.
For compressible fluids (condensate, steam and gases) the expansion factor is
.
The most popular engineering correlation covering various tapping arrangements is given by ISO5167:
| LaTeX Math Block |
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| anchor | \epsilon |
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| alignment | left |
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\epsilon = 1 - (0.41 + 0.35 \, \beta^4) \cdot \frac{\Delta p}{\kappa \cdot p_{out}} |
where
See also
Physics / Fluid Dynamics / Pipe Flow Dynamics / Pipe Flow Simulation (PFS) / Pipeline Choke @model
[ Orifice Plate Discharge Coefficient ]
Pipeline Engineering / Pipeline / Choke
