Airflow through large vertical openings in multizone modelling

In multizone models used to predict thermal comportment of buildings and inside air quality, representation of the airflow through large vertical openings is very important. Both physical representativeness and numerical stability of the large opening model are essential for a successful multizone modelling.
The widely used, Bernoulli equation based model is compared to a new proposition. In the new model the large opening space is divided into two parts, and the horizontal pressure gradient is assumed constant over each part. The resulting expression of the mass flow is numerically simpler and more stable for the practical implementation. A very good agreement is found between the physical comportment of the new model and the usual, hydrostatic pressure based model. The transient comportment of both models is validated using published experimental results of a two-cell test facility.