Bi-directional compression fan rotor for a gas turbine engine

Abstract

A fan rotor has a hub, and a plurality of axial flow fan blades extending radially outwardly of the hub. A radial compressor impeller is positioned radially inwardly of the fan blades. The radial compressor impeller has an upstream inlet which extends generally in an axial direction defined by an axis of rotation of the hub. The radial flow compressor impeller has an outlet that extends radially outwardly of the inlet, and into a supply passage for supplying air to a core engine. An engine is also disclosed.

Claims

1. A fan rotor comprising: a hub; a plurality of axial flow fan blades extending radially outwardly of said hub; and a radial compressor impeller positioned radially inwardly of said fan blades, and within said hub, said radial compressor impeller having an upstream inlet that extends generally in an axial direction defined by an axis of rotation of said hub, and said radial compressor impeller having an outlet that extends radially outwardly of said inlet, and into a supply passage for supplying air to a core engine.

2. The fan rotor as set forth in claim 1, wherein said radial compressor impeller having a plurality of circumferentially spaced blades, and there being intermediate radial vanes providing structural support between said hub and a radially inner portion of said hub.

3. The fan rotor as set forth in claim 1, wherein air delivered by said fan blades is driven into a bypass duct as propulsion air.

4. The fan rotor as set forth in claim 1, wherein said fan rotor is driven to rotate through a gear reduction.

5. A gas turbine engine comprising: a fan, a compressor, a combustor, and a turbine, said turbine including a fan drive turbine which drives said fan through a gear reduction; and the fan including a hub, and a plurality of axial flow fan blades extending radially outwardly of said hub, and a radial compressor impeller positioned radially inwardly of said fan blades, and within said hub, said radial compressor impeller having an upstream inlet that extends generally in an axial direction defined by an axis of rotation of said hub, and said radial compressor impeller having an outlet that extends radially outwardly of said inlet, and into a supply passage communicating to the compressor.

6. The engine as set forth in claim 5, wherein said radial compressor impeller having a plurality of circumferentially spaced blades, and there being intermediate radial vanes providing structural support between said hub and a radially inner portion of said rotor.

7. The engine as set forth in claim 5, wherein air delivered by said fan blades is driven into a bypass duct as propulsion air.

8. The engine as set forth in claim 5, wherein said fan is driven to rotate by said fan drive turbine through a gear reduction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically shows a gas turbine engine.

(2) FIG. 2 shows an inventive fan arrangement.

DETAILED DESCRIPTION

(3) Referring to FIG. 1, a gas turbine engine 10 includes a fan section 12, a compressor section 14, a combustor section 16, and a turbine section 18. Air entering into the fan section 12 is initially compressed and fed to the compressor section 14. In the compressor section 14, the incoming air from the fan section 12 is further compressed and communicated to the combustor section 16. In the combustor section 16, the compressed air is mixed with fuel and ignited to generate a hot exhaust stream 28. The hot exhaust stream 28 is expanded through the turbine section 18 to drive the fan section 12 and the compressor section 14. In this example, the gas turbine engine 10 includes an augmenter section 20 where additional fuel can be mixed with the exhaust gasses 28 and ignited to generate additional thrust. The exhaust gasses 28 flow from the turbine section 18 and the augmenter section 20 through an exhaust liner assembly 22.

(4) FIG. 2 shows a fan rotor 79, which may be incorporated into an engine such as shown in FIG. 1. Rotor 79 rotates along an axis X directly driven by a turbine 201 (shown schematically). This application extends to use where a reduction gearbox 80 (shown schematically) may be positioned between the rotor 79 and turbine 201 to separate the fan and turbine rotational speeds for their respective aerodynamic efficiencies. The reduction gearbox 80 rotates a shaft 82.

(5) Housing 84 and 86 sits axially inward of the fan rotor 79.

(6) A fan blade 92 is generally as known, and is an axial flow fan blade positioned outwardly of a hub 94. The fan blades 92 deliver air into a bypass duct 93, as bypass or propulsion air.

(7) Inwardly of the hub 94 is a radial compressor impeller 101 including compressor blades 196. The impeller 101 takes in air from an axial upstream inlet 97 and compresses it to a radial outlet 99 at a downstream location. Downstream of the outlet 99, the air exits into a passage 100, which is sealed by an air seal 90. From passage 100, the air reaches passage 88, and is then delivered into a compressor 110 (shown schematically).

(8) The described arrangement thus utilizes different fan rotor sections for providing the bypass air to bypass duct 93, and for providing air that is already compressed into the outlet 88 leading to compressor 110. The use of the radial compressor impeller 101 results in a relatively axially compact arrangement. Still, the radial compressor impeller 101 provides a good deal of compression work on the air, and thus increases the efficiency of the overall engine.

(9) A plurality of struts 96 (shown in phantom) may extend between the hub 94 and inner mount structure 115 to provide structural support for rotor 79. Struts 96 may be located between each circumferentially spaced pair of blades 196. Alternatively, a plurality of blades 196 may be formed to work as structural struts, in addition to their intended aerodynamic functions.

(10) The fan rotor 79 includes a hub 94, a plurality of axial flow fan blades 92 extending radially outwardly of the hub, and a radial compressor impeller 101 positioned radially inwardly of the fan blades 92. Within the hub 94, the radial compressor impeller 101 has an upstream inlet 97 that extends generally in an axial direction defined by an axis of rotation X of the hub. The radial compressor impeller 101 has an outlet 99 that extends radially outwardly of the inlet 97, and into a supply passage 100/88 for supplying air to a core engine.

(11) Packaging the radial compressor impeller 101 within the fan hub 94, will allow increased compression capability to core airflow for a given engine. As a result, an engine overall length may be reduced by eliminating one or more downstream compressor stages leading to reduced engine weight, and consequently, less fuel burn. Alternatively, retaining all compressor stages for a given engine may enable higher compressor inlet-to-outlet pressure ratio that may also lead to less fuel burn.

(12) Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.