scope:

ABSTRACT

Implementation of centrifugal fans into the built environment is common in industry today. Centrifugal fans are an efficient and economical option capable of producing the pressure and airflow required for modern building systems. This research uses computational fluid dynamics to investigate how fan performance is impacted by suction chamber intrusions and the proximity of the housing wall to the fan discharge. Current industry trends show the motor being moved further into the suction chamber of the fan. The proximity of the housing to the fan discharge influences the efficiency of the fluid flow. It is desirable to understand the impact both cases have on fan performance in order to balance manufacturing with a compact efficient design. Intrusions into the suction chamber and housing proximity both have clear design conditions that should be avoided. The depth of the suction chamber intrusion is seen to marginally affect the performance of the fan within the same operating zone until the motor-cap is inserted over 50% of the total depth of the suction chamber. Beyond this point a clear reduction of performance occurs as the minimum pressure is pushed outside the suction chamber. An optimal housing proximity of 135% of the fan diameter, for this system, achieves maximum total efficiency. Shrinking the housing below this value is detrimental to performance.