Orifices

Orifices for speed control

Symbol orifices

Symbol orifices

In contrast to the throttle, the ratio of length L compared to flow diameter d is small.
Guide value: L / d <1.5

swirls at an hydraulic orifice

swirls at an hydraulic orifice

Advantage of the orifice is that the viscous fluid friction is very low and thus the flow rate hardly depends on the viscosity. Disadvantage are the swirls especially at the exit point of the aperture.

Pressure drop measured at an orifice

Pressure drop measured at an orifice