Ducted fan with inlet vanes and deswirl vanes

The present invention relates generally to air processing techniques, and in particular to a fan apparatus having improved output capacity.

Developments and operations of high density integrated circuits, high-power electronics, avionics, and advanced telecommunication equipment usually are associated with the generation of large amounts of heat. How to dissipate this heat quickly and effectively is an important concern. A widely used solution is air cooling with a fan apparatus. Conventional cooling fans typically run at relatively low rotational speeds, e.g., 15,000 RPM (rotations per minute) or lower. In order to drive up the rotational speeds, a ducted fan can be used to provide more air flow at high pressure while keeping the size of the ducted fan frame the same.

One conventional ducted fan configuration includes just a single set of stationary vanes (usually used as inlet guide vanes) followed by a single rotating impeller. The flow of air processed by such a conventional ducted fan is deficient in the flow\'s directional guidance and is lacking in output capacity in terms of pressure enhancement. Another configuration of a ducted fan is that an even-numbered rotating and stationary vane sets are alternatively grouped together. This configuration has been used in some traditional aircraft engine compressors. But, it is not suit for new small form-factor aircraft propulsion systems for UAV\'s (unmanned air vehicles).

Therefore, the prior art is lacking to meet the specific requirements mentioned above and beyond in terms of the particular constructional improvements of the invention described in detail hereinafter.

The nature of the improvements for a ducted fan with both inlet guide vanes and deswirl vanes is brought out more clearly in the detailed description hereinafter of an embodiment of the present invention.

Embodiments of the present invention relate generally to air processing techniques, and in particular to a fan apparatus that integrally combines a rotating impeller disposed between an upstream set of stationary inlet guide vanes and a downstream set of stationary deswirl vanes. Merely by way of example, such fan apparatus is constructed in a ducted housing with unique arrangements for the rotating impeller blades and upstream/downstream stationary vanes for enhancing fan performance at high rotational speeds. But it would be recognized that the invention has a much broader range of applicability.

In a specific embodiment, the present invention provides a fan apparatus. The fan apparatus includes a ducted housing with an axis of rotation including a first section and a second section. Additionally, the fan apparatus includes a first plurality of vanes being radially coupled within the first section and a second plurality of vanes being radially coupled within the second section. Moreover, the fan apparatus includes an impeller with a plurality of blades rotatably disposed within the ducted housing between the first plurality of vanes and the second plurality of vanes for rotary motion about the axis of rotation. With respect to the ducted housing, the first plurality of vanes are stationary in a first arrangement to guide an inflow of air towards the impeller. The plurality of blades are rotary in a second arrangement to have a rotational direction substantially opposite to the inflow of air guided by the first arrangement. The second plurality of vanes are stationary in a third arrangement to diffuse an outflow of air substantially along the axis of rotation.

In another specific embodiment, the present invention provides a ducted fan apparatus. The ducted fan apparatus includes a housing enclosing an interior volume from a first end section to a second end section along an axis of rotation. The ducted fan apparatus further includes a first plurality of vanes being radially connected a stationary center core with respective surface positions of the interior volume of space near the first end section. Additionally, the ducted fan apparatus includes a second plurality of vanes being radially connected a stationary central structure with respective surface positions of the interior volume of space near the second end section. Moreover, the ducted fan apparatus includes an impeller including a plurality of blades rotatably disposed between the first plurality of vanes and the second plurality of vanes within the interior volume of space for rotary motion about the axis of rotation. Accordingly, each of the first plurality of vanes is in airfoil shape arranged with a first inlet angle and a first exit angle associated with a first tangential direction relative to the axis of rotation. Each of the plurality of blades is in airfoil shape arranged with a second exit angle and a second inlet angle associated with a second tangential direction relative to the axis of rotation. Each of the second plurality of vanes is in airfoil shape arranged with a third inlet angle and a third exit angle relative to the axis of rotation. Furthermore, the first tangential direction is substantially opposite to the second tangential direction and the first inlet angle and the third exit angle each is substantially equal to zero.

In an alternate embodiment, the invention provides an apparatus for fluid flow processing application. The apparatus includes a ducted housing including a first section and a second section. The first section is mounted with the second section to share an axis of rotation. Additionally, the apparatus includes a fan unit disposed within the ducted housing. The fan unit consists of a first plurality of vanes, an impeller, and a second plurality of vanes. The first plurality of vanes are fixedly connected between the ducted housing and a stationary center core within the first section. The second plurality of vanes are fixedly connected between the ducted housing and a stationary central structure within a portion of the second section. The impeller includes a plurality of blades disposed between the first plurality of vanes and the second plurality of vanes for rotary motion about the axis of rotation. Correspondingly, the stationary center core and the stationary central structure are co-axial with the axis of rotation. The first plurality of vanes are arranged in a first arrangement for redirecting an inflow of fluid substantially along the axis of rotation to a direction substantially opposite to rotational direction of the plurality of blades. The plurality of blades are arranged in a second arrangement to swirl the redirected inflow of fluid, the second arrangement being associated with the first arrangement. The second plurality of vanes are arranged in a third arrangement for diffusing an outflow of fluid substantially along the axis of rotation, the third arrangement being associated with the second arrangement.

Many benefits are achieved by applying embodiments of the present invention. Certain embodiments of the invention provide a ducted fan apparatus with a unique combination of a single rotating impeller disposed between two sets of stationary vanes. This can be configured to operate at relative high rotational speeds of 30,000 rpm or higher compared to conventional cooling fan running at speed of 15,000 rpm or lower. Additionally, the ducted fan configured according to certain embodiment of the present invention also advantageously differs from convention ducted fans with either a single set of stationary vanes at upstream or downstream of an rotating impeller. The advantage relies on the improved pressure compression characteristics. For example, the ducted fan according to an embodiment of the present invention can provide more air flow with pressure enhanced by about 20% while keeping the same fan frame size. Thus, the cooling efficiency of the fan is greatly improved. This is especially useful for effectively dissipate heat generated by many high-power and dense electronics, avionics, and telecommunication equipments. Alternatively, the ducted fan structure according certain embodiments of the present invention can also be applied for a small aircraft propulsion systems such as UAV\'s due to the superior performance on high rotational speeds to handle large amount of air flow with high pressure.