| 摘要 |
A blade for a vehicle engine-cooling fan assembly. The blade combines a particular distribution of four, key, blade-design parameters-planform sweep, airfoil chord, maximum airfoil camber, and airfoil pitch angle-to achieve a fan assembly having high pumping, high efficiency, and low noise. Specifically, the blade has a planform with a forward sweep angle continuously increasing in absolute value along the span from the root to a maximum absolute value not exceeding about 15 degrees at the tip. The airfoil of the blade has a chord that continuously increases from the root to the tip, a maximum camber that continuously decreases from a value not greater than about 12% of chord at the root to a value not less than about 5% of chord at the tip, and a solidity not greater than about 1.1 at the root and not less than about 0.5 at the tip. The pitch angle of the airfoil of the blade defines three, separate regions: (a) a first region in which the pitch angle continuously decreases from the root, where the pitch angle has a value not exceeding about 120% of the tip pitch angle, to about the +E,fra 1/2+EE -span location; (b) a second region in which the pitch angle continuously increases from about the +E,fra 1/2+EE -span location, where the pitch angle has a value not less than about 80% of the tip pitch angle, to about the +E,fra 7/8+EE -span location; and (c) a third region in which the pitch angle continuously decreases from about the +E,fra 7/8+EE -span location, where the pitch angle has a value not exceeding about 105% of the tip pitch angle, to the tip.
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