Noise and Performance of Automotive Cooling Fans 800031
It is important to know the noise and performance characteristics of different engine-cooling-fan designs when making a selection for a particular application. Convenient parameters such as specific diameter, specific speed, efficiency and sound-power-level coefficient relate the geometrical performance and noise characteristics of a fan to the aerodynamic requirements of the system. Fan characteristics expressed in these parameters show clearly: the relationship between efficiency and noise; the effect of various geometric variables on efficiency and noise; comparisons of noise, performance, and other characteristics between different fan designs in performing a given pumping task.
GM Research studies show that the peak efficiency and minimum noise operating points of a fan do not necessarily coincide. Therefore, the judicious use of both noise and performance characteristics is important in selecting the best fan design for a given application. These studies also show that decreasing tip clearance, decreasing pitch angle, and increasing chord at a given solidity will increase fan efficiency, while decreasing tip clearance, optimizing pitch angle, optimizing camber, and optimizing solidity will reduce fan noise.