ESDU TN 10013:2011

This Technical Note discusses the studies conducted by ESDU for
the CFD validation of the predictions for pressure loss, discharge
coefficient and flow characteristics in square-edged orifice
plates. These studies used the validation data from the literature
reviewed in ESDU TN 07007.

The purpose of this work was to generate validated CFD
predictions for:

• square-edged and knife-edged orifice plates, free of burrs and
other contaminants,

• circular, concentric orifices in circular pipes with identical
upstream and downstream cross-sectional areas,

• fully-developed flow conditions upstream and downstream of the
orifice,

•swirl-free, steady flow conditions with no cross-flow upstream
or downstream of the orifice plate and flow normal to the orifice
plate,

• laminar, transitional and turbulent flow regimes,

• single-phase, Newtonian liquids and gases in incompressible
flow (Mach number = 0.3 at the vena contracta plane).

The CFD validation studies covered the following geometrical
configurations and pipe Reynolds numbers:

• orifice to pipe diameter ratios: 0.3 = ß = 0.7; orifice
thickness to diameter ratios: 0.01 = t/d = 5.0.

• pipe Reynolds number: 10 = Re_D =
10⁵.

Based on the comparisons of the ESDU CFD predictions with the
experimental data in the literature, best practice guidelines are
provided for the modelling of the flow characteristics and pressure
loss in square-edge orifice plates.