we are using thermal liquid, hydraulic and pneumatic domain a lot, but face problems with the flow discharge coefficient Parameter all the time. Example: I would like to parameterize the "variable area pneumatic orifice" block like the "Constant Area Pneumatic Orifice (ISO 6358)" block, i.e. using Kv/Cv coefficient instead of flow discharge coefficient (Cd). Alternatively a conversion formula from cd to Kv/Cv would be helpful. Most formulas I found are incorrect or use specific gravity or effective orifice area and thus are not helpful.
You could use this one for liquids:
DN=inner pipe diameter
But this one won't work for gases, since pressure and density after the orifice is not known.
In the German/European market all valve datasheets only contain Kv values for gas and liquid valves.
(this concerns thermal liquid and hydraulic orifice blocks as well).
Thanks in advance for any advice