Evaluation of some assumptions used in multizone airflow network models

Multizone airflow network models assume that in a zone air temperature and contaminant concentrations are uniform, and air momentum effects are neglected. These assumptions could cause errors for airflow with strong buoyancy, large contaminant concentration gradient, or strong momentum. This study has found the correlations of the errors and some dimensionless air parameters. The assumption of uniform air temperature is acceptable when the dimensionless temperature gradient is smaller than 0.03. The assumption of uniform contaminant concentration is valid if the corresponding Archimedes number for the source zone is greater than 400. The assumption of neglecting air momentum effect is reasonable when the jet momentum effect is dissipated before reaching an opening in downstream.

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