Patent ID: 6565323
Filing Date: 2003-05-20
Classification: F04D,Y10S

Abstract:
A propeller fan, the fan including a plurality of vanes, each vane fixed at a hub secured at a rotary axle, having a first vane length toward external radial direction thereof and circumferentially spaced out at a gap between the other vanes in said plurality of vanes, wherein each vane has a cross-sectional shape including a substantially flat surface at an external side of a leading edge thereof, and an external side of a trailing edge thereof is bent with a first vane radius of curvature (RC), wherein the radius of curvature (RC) satisfies a formula of RC=0.55&it;â€ƒ&it;to&it;â€ƒ&it;0.6RL=0.55&it;â€ƒ&it;to&it;â€ƒ&it;0.612&it;2&it;v&it;â€ƒ&it;R&it;â€ƒ&it;e&varpi;=0.55&it;â€ƒ&it;to&it;â€ƒ&it;0.612&it;2&it;v&it;â€ƒ&varpi;&it;U&it;â€ƒ&it;R&it;â€ƒLv=1.1&it;â€ƒ&it;to&it;â€ƒ&it;1.22&it;U&it;â€ƒ&it;RL&varpi;,where &ohgr; is angular velocity of the fan U is maximum rotating speed of the vane RL is the radial distance of the vane, and RL=12&it;2&it;v&it;â€ƒ&it;R&it;â€ƒ&it;eÏ‰,where &ngr; is coefficient of kinematic viscosity, Re is critical Reynolds number and &ohgr; is angular velocity of the fan.