Noise Reduction of Pressure Type Fans for Automobile Air Conditioners

Abstract

Automotive air conditioners often employ a pusher-type condenser cooling system. Because the axial fan in such cooling systems is a major source of noise in the engine compartment, much effort has been directed to reducing the noise emitted by the fan. This paper clarifies the mechanism by which the fan of a pusher-type cooling system generates noise and presents ways to decrease the turbulent noise from it. Detailed studies of the flow around the fan were made using computer simulations and LDA (Laser Doppler Anemometer) measurements. A considerable reduction in the noise level of pusher-type cooling system has been achieved for different resistances without any deterioration in performance.