A Method for Calculating a Ventilation Bypass Factor

Abstract

The ventilation bypass factor (marked as S) is a simple and straightforward indicator describing the fraction of the supply air that bypasses the occupied zone of a ventilated room. Except for some special circumstances, this factor is very difficult to estimate quantitatively. In this article, a method for calculating S by computational fluid dynamics tools is proposed. Fine particles with small inertia that can be regarded as moving integrally with air are released at the air supply inlet to represent the air path lines. S is calculated by stating the trajectories of the particles that enters/bypasses the occupied zone. A ventilation situation is modelled numerically to demonstrate the detailed procedure of the method. This new method makes it possible to estimate quantitatively the ventilation bypass factor and use it as a guide for ventilation design.

Keywords

Bypass factor Particle tracking CFD Ventilation effectiveness

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