Target flowmeters measure flow by measuring the amount of force exerted by the flowing fluid on a target suspended in the flow stream. The force exerted on the target by the flow is proportional to the pressure drop across the target.
When flow medium flows through measure tube, the pressure will force on the target because of
the flow kinetic energy. It is known that the pressure value forcing on the target can be expressed as
F=CDAPU2 /2
where,
F — Pressure on the target
CD— Damp index
A — Area of the target on axial projection to measure the tube
P — Medium density
U — Mean velocity of the medium