Asymmetric flow extraction system
A system for asymmetric flow extraction is described and claimed, the system comprising a flow path, a bleed slot in the flow path, a bleed cavity for receiving at least a portion of the fluid extracted from the flow path and a bleed passage in flow communication with the bleed slot and the bleed cavity wherein the bleed passage has at least one deflector having a shape such that the width of the bleed passage cross section varies in a direction normal to the direction of fluid flow in the bleed passage. In another embodiment, the deflector has an aerodynamic surface having a shape such that the flow passage between the aerodynamic surface and a surface located away from it has a cross sectional shape that is non-axisymmetric. In another embodiment, the bleed passage comprises an assembly of a plurality deflectors, arranged circumferentially.
1. A system for asymmetric flow extraction comprising:
a flow path for flowing a fluid there-through;
a bleed slot in the flow path for extracting a portion of the fluid from the flow path;
a bleed cavity for receiving at least a portion of the fluid extracted from the flow path;
a bleed passage in flow communication with the bleed slot and the bleed cavity;
wherein the bleed passage has at least one deflector having a shape such that the width of the bleed passage cross section varies in a direction normal to the direction of fluid flow in the bleed passage; and,
wherein the bleed cavity is in flow communication with a plurality of bleed ports located asymmetrically in the circumferential direction and in which said bleed ports remove the fluid from the bleed cavity.
2. A system according to claim 1 wherein the bleed passage comprises a plurality of flow sectors in the circumferential direction.
3. A system according to claim 2 wherein the plurality of flow sectors is formed by a plurality of deflectors arranged circumferentially.
4. A system according to claim 1 wherein the bleed passage comprises a first flow sector having a first width, a second flow sector having a second width, and at least one transitional flow sector located circumferentially between the first flow sector and the second flow sector.
5. A system according to claim 1 wherein the bleed passage comprises a plurality of arcuate deflectors arranged circumferentially.
6. A system according to claim 1 wherein the at least one deflector has an aerodynamic shape such that variation of the flow rate at the bleed slot in the circumferential direction is reduced.
7. A system according to claim 1 wherein the bleed passage has a portion wherein the fluid extracted from the flow path is diffused.
8. A system according to claim 1 wherein the bleed cavity is in flow communication with a means for removing the fluid from the bleed cavity.
9. A deflector assembly for forming a bleed passage comprising:
a first sector having a first aerodynamic surface such that the flow passage between the first aerodynamic surface and a surface located away from it has a first cross sectional shape that does not change in the circumferential direction;
a second sector having a second aerodynamic surface such that the flow passage between the second aerodynamic surface and a surface located away from it has a second cross sectional shape that does not change in the circumferential direction;
a third sector having a third aerodynamic surface such that the flow passage between the third aerodynamic surface and a surface located away from it has a cross sectional shape that varies from the first cross sectional shape to the second cross sectional shape in the circumferential direction; and
a fourth sector having a fourth aerodynamic surface such that the flow passage between the fourth aerodynamic surface and a surface located away from it has a cross sectional shape that varies from the second cross sectional shape to the first cross sectional shape in the circumferential direction.
10. A deflector assembly according to claim 9 wherein the first cross sectional shape has a smaller area than the second cross sectional shape
11. A deflector assembly according to claim 10 wherein the first sector is located in circumferential proximity to a bleed port that extracts a larger amount of bleed flow.