MODELING FAN AND PERFORATED VENTILATION DUCTS FOR AIRFLOW BALANCE POINT
A model was developed to select the most effective fan for a perforated ventilation duct, based on the optimum 
air distribution pattern in the room. The model was formulated in two parts: (1) to predict the airflow performance of 
perforated ventilation ducts and to evaluate the outlet air discharge; (2) to determine the balance point between the fan 
and the duct by assuming their effective outlet areas to be equal. The experiment validated the first part and tested the 
hypothesis involved in the second part. When compared with the experimental results obtained from three wooden 
perforated ventilation ducts with aperture ratios of 0.5, 1.0, and 1.5, the model predicted the outlet airflow along the full 
length of a perforated duct operated under turbulent flow with a maximum error of 9%. The assumption of a common 
effective outlet area was valid and the model was extended to determine the balance point operation between the fan and 
the perforated duct.