Rotor arrangement
With highly loaded rotors and stators problems can occur with secondary flows sweeping low momentum fluid across the blades reducing efficiency. By provision of collector slots to collect the secondary air and direct that air to a return slot in a rotor hub it is possible to provide impetus to the collected secondary flow to an outlet slot such that there is dispersal of the secondary flow and therefore reduce the effects upon the overall performance of a gas turbine engine incorporating the arrangement.
1. A rotor arrangement for a gas turbine engine, the arrangement comprising a rotor hub and a stator shroud arranged to sweep past each other in use, the stator shroud including a collector slot to collect secondary flow and direct the collected secondary flow to a return slot in the rotor hub, the return slot shaped to provide in use impulse to the collected secondary flow to project the collected secondary flow to an outlet slot in the stator shroud, the collector slot and the outlet slot respectively angled relative to the return slot to facilitate coupling as the rotor hub sweeps past the stator shroud in use.
2. An arrangement as claimed in claim 1 wherein the collector slot has an inlet in an upper surface of the stator shroud.
3. An arrangement as claimed in claim 2 wherein the collector slot has a collector passage at an angle towards the direction of rotation of the rotor hub in use.
4. An arrangement as claimed in claim 3 wherein the inlet has a sharp bend into the collector passage.
5. An arrangement as claimed in claim 1 wherein the outlet slot has an outlet in the upper surface of the stator shroud.
6. An arrangement as claimed in. claim 5 wherein the outlet slot has an outlet passage at an angle away from the direction of rotation of the rotor hub in use.
7. An arrangement as claimed in claim 6 wherein the outlet extends with a rounded bend from the outlet passage.
8. An arrangement as claimed in claim 1 wherein the collector slot has a collector passage at an angle towards the direction of rotation of the rotor hub in use and the outlet slot has an outlet passage at an angle away from the direction of rotation of the rotor hub in use, and wherein the outlet passage has a greater width than the collector passage.
9. An arrangement as claimed in claim 1 wherein the collector slot has an inlet in an upper surface of the stator shroud and the outlet slot has an outlet in the upper surface of the stator shroud, and wherein the outlet has a greater width than the inlet.
10. An arrangement as claimed in claim 1 wherein the return slot is rounded.
11. An arrangement as claimed in claim 1 wherein the return slot is half moon shaped.
12. An arrangement as claimed in claim 1 wherein the return slot is angled away from the direction of rotation of the rotor hub in use.
13. An arrangement as claimed in claim 1 wherein there is a plurality of collector slots and/or return slots and/or outlet slots.
14. A gas turbine engine including a rotor arrangement as claimed in claim 1 .