Device for tuning clearance in a gas turbine, while balancing air flows

1. A device for tuning clearance at rotor blade tips in a gas turbine rotor, comprising:

at least one annular air flow duct that is mounted around the circumference of an annular casing of a stator of the turbine, said annular air flow duct being designed to discharge air onto said casing in order to modify the temperature thereof;

a tubular air manifold, at least a portion of which is disposed around the air flow duct(s);

at least one air feed tube for feeding the tubular air manifold with air; and

at least one air pipe opening in the tubular air manifold and opening out into the air flow duct(s);

wherein the air pipe is provided with means for balancing the air flowing through said pipe.

2. A device according to claim 1 , wherein the air pipe is provided with a balancing diaphragm for balancing the air flowing through said pipe.

3. A device according to claim 2 , wherein the diaphragm is disposed at an entrance of the air pipe so as to create additional head losses.

4. A device according to claim 3 , wherein the diaphragm comes in the form of a ring having an inside diameter d 1 that is smaller than the inside diameter d 2 of the air pipe.

5. A device according to claim 1 , including two tubular air manifolds, each manifold being connected to three air pipe, each air pipe opening out into three air flow ducts, each air pipe being provided with a balancing diaphragm for balancing the air flow going through said pipe.

6. A device according to claim 5 , wherein the characteristics of each diaphragm are individualized to match the air pipe in which said diaphragm is placed.