Measurements of the Mean Flow Velocity and Velocity Fluctuations at the Exit of an FC Centrifugal Fan Rotor

Abstract

The flow from a small forward curved fan rotor was studied to provide guidance for fan design. The single width fan had a 0.23 m rotor containing 48 blades. It is typical of the centrifugal fans used in small air-conditioning units. Visualization techniques and hot wire measurements showed the rotor flow to be highly turbulent and strongly three-dimensional. The inlet flow was found to fill only 3/4 of the blade span. The shroud end of the rotor was an inactive or separated region. A jet-wake pattern occurred at the blade exit in the active flow region. The inlet flow separated at the leading edge of the blade suction surface. Design changes are offered to improve the performance of FC fans.