The concentrations of indoor pollutants should be maintained below recommended values at all occupied locations at any time. A design method based on minimal air change rates may not be satisfactory, since the ventilation effectiveness is determined not only by the nominal air exchange rate but also many other factors, such as the airflow pattern the space, location of contaminant sources, and properties of the contaminants. It is the objective of the present study to investigate numerically the effect of airflow patterns due to the various factors of ventilation effectiveness.
The measurements reported in this paper were carried out in a mock up of an office room, ventilated by a commercial supply air terminal consisting of 84 nozzles (characteristic dimension SqRoot of As = 0.0975 m). The test room configuration was identical to the one used within the IEA Annex 20 work. Results from isothermal supply is reported. A constant-temperature hot-film anemometer with fast dynamic response was used torecord the instantaneous velocities.
The influence of the Reynolds number on low speed flow (essentially incompressible flow) is discussed. A first set of literature is reviewed to identify effects of low Reynolds number on flows in rooms. Methods of incorporating low-Reynolds-number effects in existing turbulence models are surveyed.