Clearance control arrangement
A clearance control arrangement includes first and second components defining a clearance therebetween. The first component includes a surface portion having at least a layer of material that changes thickness when actuated. The clearance control arrangement also includes an actuator to actuate the layer of material.
1. A clearance control arrangement comprising:
first and second components defining a clearance therebetween;
the first component comprising a surface portion having at least a layer of piezoelectric material that changes thickness when actuated; and
an actuator to actuate the layer of piezoelectric material.
2. A clearance control arrangement as claimed in claim 1 comprising a plurality of first components each defining a clearance relative to the second component and each having at least a layer of piezoelectric material that changes thickness when actuated.
3. A clearance control arrangement as claimed in claim 2 wherein the actuator actuates all the layers of material in synchronicity.
4. A clearance control arrangement as claimed in claim 2 wherein an actuator is provided to actuate each layer of material individually.
5. A clearance control arrangement as claimed in claim 1 wherein the actuator comprises a voltage source.
6. A clearance control arrangement as claimed in claim 1 , wherein the surface portion comprises the layer of piezoelectric material sandwiched between layers of metal.
7. A clearance control arrangement as claimed in claim 6 wherein the voltage source is connected to the layers of metal across the layer of piezoelectric material.
8. A clearance control arrangement as claimed claim 1 further comprising a controller to control actuation of the actuator.
9. A clearance control arrangement as claimed in claim 8 further comprising a feedback loop between the sensor output and the controller.
10. A clearance control arrangement as claimed in claim 9 wherein the sensor is coupled to the surface portion.
11. A clearance control arrangement as claimed in claim 9 wherein the sensor is coupled to another part of the first component.
12. A clearance control arrangement as claimed in claim 1 further comprising a sensor to determine the clearance.
13. A clearance control arrangement as claimed in claim 12 wherein the sensor is coupled to the surface portion.
14. A clearance control arrangement as claimed in claim 12 wherein the sensor is coupled to another part of the first component.
15. A gas turbine engine comprising a clearance control arrangement as claimed in claim 1 .
16. A gas turbine engine according to claim 15 comprising a clearance control arrangement for tip clearance control wherein the first component comprises a casing segment and the second component comprises a rotating blade.
17. A gas turbine engine according to claim 16 further comprising a cooling arrangement for cooling the casing segment.
18. A gas turbine engine comprising a clearance control arrangement as claimed in claim 1 for fan duct acoustic control.