This information is part of the Modelica Standard Library maintained by the Modelica Association.

This component models a thick edged orifice with sharp corners in the overall flow regime for incompressible and single-phase fluid flow through an arbitrary shaped cross sectional area (square, circular, etc.) considering influence of surface roughness. It is expected that also compressible fluid flow can be handled up to about Ma = 0.3. It is assumed that neither mass nor energy is stored in this component. In the model basically a function is called to compute the mass flow rate as a function of pressure loss for a thick edged orifice. Also the inverse of this function is defined, and a tool might use this inverse function instead, in order to avoid the solution of a nonlinear equation.

The details of the model are described in the documentation of the underlying function.