초록 ▼

A fan system, such as a turbofan, marine propeller, or a cooling fan, includes a fan noise control system for reducing noise generated by the fan system. The noise control system may be configured to reduce either broadband noise, blade-passage noise, or both. In particular, the fan noise control sy

A fan system, such as a turbofan, marine propeller, or a cooling fan, includes a fan noise control system for reducing noise generated by the fan system. The noise control system may be configured to reduce either broadband noise, blade-passage noise, or both. In particular, the fan noise control system suitably includes a pre-swirl generator configured to provide a layer of fluid upstream from the fan blades. The layer swirls in the direction of the fan's rotation, reducing the angular velocity differential between the fan blades and the incident fluid. In addition, the fan noise control system may also include a fluid seal generator configured to create a fluid barrier between the fan blade tips and the interior surface of the fluid flow channel. The fluid seal inhibits leakage flow between the fan blade tips and the interior surface as well as the formation of blade vortices. By minimizing the blade wake and the blade tip vortices without adding solid surfaces, noise tends to diminish.

대표청구항 ▼

[ What is claimed is:] [1.]1. A fan noise control system for controlling noise generated by a fan having an upstream direction, a downstream direction, and an interior surface defining a fluid flow channel, said fan noise control system comprising:a pre-swirl generator configured to reduce fan noise

[ What is claimed is:] [1.]1. A fan noise control system for controlling noise generated by a fan having an upstream direction, a downstream direction, and an interior surface defining a fluid flow channel, said fan noise control system comprising:a pre-swirl generator configured to reduce fan noise by providing a layer of rotating fluid upstream of the fan, wherein the pressure of said layer of rotating fluid is substantially uniform at every angle in a plane parallel to the lane of rotation of said fan, wherein said layer of rotating fluid follows said interior surface in accordance with the Coanda effect.