Particle extraction system for a gas turbine engine

1. A gas turbine engine comprising:

an engine core including at least one compressor, a combustor downstream of the compressor, and at least one turbine downstream of the combustor;

a primary flowpath fluidly connecting each of the compressor, the combustor, and the turbine;

at least one particle extraction duct having an extraction duct inlet connected to said primary flowpath fore of all compressors in the engine core and an extraction duct outlet connected to a bypass flowpath; and

wherein the primary flowpath includes an outer diameter radius change in excess of 20% of a span of a core inlet guide vane from a primary flowpath inlet to a compressor inlet.

2. The gas turbine engine of claim 1 , wherein the at least one particle extraction duct is a plurality of particle extraction ducts arranged circumferentially about an engine centerline.

3. The gas turbine engine of claim 2 , wherein the particle extraction ducts are evenly circumferentially spaced.

4. The gas turbine engine of claim 1 , wherein the extraction duct outlet is downstream of a fan exit guide vane, relative to an expected fluid flow through a fan duct.

5. The gas turbine engine of claim 1 , wherein the extraction duct inlet includes a lip at least partially intersecting an expected debris path.

6. The gas turbine engine of claim 5 , wherein the expected debris path follows a contour of an outer diameter of the primary flowpath.

7. The gas turbine engine of claim 5 , wherein the lip extends radially inward beyond an outer diameter of the primary flowpath.

8. The gas turbine engine of claim 1 , wherein the primary flowpath inlet is oversized by a volume approximately equal to a volume of air extracted by said at least one particle extraction duct.

9. A method for removing debris from a gas turbine engine comprising:

providing a particle extraction duct including an extraction duct inlet connected to a primary flowpath fore of all compressors in an engine core and an extraction duct outlet connected to a fan duct, wherein the primary flowpath includes an outer diameter radius change in excess of 20% of a span of a core inlet guide vane from a primary flowpath inlet to a compressor inlet of a portion of the engine core housing a first compressor and a second compressor;

passing debris from an expected debris path through said extraction duct inlet and through said extraction duct outlet; and

expelling the debris out an aft end of the fan duct.

10. The method of claim 9 , wherein passing debris from the expected debris path through said inlet comprises intersecting the expected debris path with a lip positioned on an aft edge of the particle extraction duct.

11. The method of claim 9 , wherein passing debris through said outlet comprises expelling debris from the particle extraction duct into the fan duct downstream of a fan exit guide vane.

12. A gas turbine engine comprising:

a core including a primary flowpath, the primary flowpath having a radially inward turn upstream of all compressor inlets of the core and downstream of a primary flowpath inlet, the radially inward turn including an inner diameter radius change in excess of 20% of a span of a core inlet guide vane from the primary flowpath inlet to the compressor inlet; and

a particle extraction duct connecting a radially outward surface of the primary flowpath to a fan duct, a particle extraction duct inlet being positioned at a base of the radially inward turn.

13. The gas turbine engine of claim 12 , wherein an outlet of the particle extraction duct is positioned downstream of a fan exit guide vane, relative to an expected direction of fluid flow through the fan duct.

14. The gas turbine engine of claim 12 , further comprising an aft lip positioned at the particle extraction duct inlet and intersecting an expected debris path.

15. A gas turbine engine comprising:

a fan upstream of an engine core;

the engine core being surrounded by a core nacelle and including at least one compressor, a combustor downstream of the compressor, and at least one turbine downstream of the combustor;

a primary flowpath fluidly connecting each of the compressor, the combustor, and the turbine; and

at least one particle extraction duct having an extraction duct inlet connected to said primary flowpath fore of said compressor and an extraction duct outlet connected to a bypass flowpath, wherein the extraction duct inlet is disposed in the core nacelle upstream of all compressors in the engine core.