Annex60.Airflow.Multizone.Orifice

# .Annex60.Airflow.Multizone.Orifice

Orifice

## Information

This model describes the mass flow rate and pressure difference relation of an orifice in the form

        V_flow = k * dp^m,

where `k` is a variable and `m` a parameter. For turbulent flow, set `m=1/2` and for laminar flow, set `m=1`. Large openings are characterized by values close to `0.5`, while values near `0.65` have been found for small crack-like openings (Dols and Walton, 2002).

#### References

- W. Stuart Dols and George N. Walton, CONTAMW 2.0 User Manual, Multizone Airflow and Contaminant Transport Analysis Software, Building and Fire Research Laboratory, National Institute of Standards and Technology, Tech. Report NISTIR 6921, November, 2002.

## Revisions

- October 8, 2013 by Michael Wetter:
  Changed the parameter `useConstantDensity` to `useDefaultProperties` to use consistent names within this package. A conversion script can be used to update this parameter.
- December 6, 2011 by Michael Wetter:
  Replaced `rho` with `rho_nominal` because `rho` is computed in an `equation` section and not in the `initial equation` section.
- July 20, 2010 by Michael Wetter:
  Migrated model to Modelica 3.1 and integrated it into the Buildings library.
- February 4, 2005 by Michael Wetter:
  Released first version.

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