Turbomachine module provided with a device to improve radial clearances

1. Turbomachine module comprising a device to improve radial clearances, comprising an outer casing ( 22 ), an inner casing ( 21 ) through which a primary turbomachine flow (Fp) passes, and at least one shock absorbing ring ( 5 ) connecting said casings, said module also comprising an annular cavity ( 43 ) on the downstream side of said shock absorbing ring ( 5 ), with a passage ( 42 ) formed in it through which an airflow ( 4 ) is drawn off from said primary flow (Fp),

characterised in that the device to improve radial clearances comprises a thermal inertia control device mounted on the shock absorbing ring ( 5 ), downstream from it, this thermal inertia control device comprising at least one coat of thermal insulation ( 8 , 90 ), and at least partly delimiting said annular cavity ( 43 ), on the downstream side of it.

2. Turbomachine comprising at least one module according to claim 1 .

3. Turbomachine module according to clam 1 , characterised in that the coat of thermal insulation is a thermal layer ( 90 ) deposited on the inner surface ( 57 ) of the inner arm ( 52 ) of the shock absorbing ring ( 5 ).

4. Turbomachine module according to claim 3 , characterised in that the thermal layer ( 90 ) is an abradable material.

5. Turbomachine module according to claim 1 , characterised in that the coat of thermal insulation ( 8 , 90 ) is in contact with an inner surface ( 57 ) of an annular arm ( 52 ) inside the shock absorbing ring ( 5 ).

6. Turbomachine module according to claim 5 , characterised in that the thermal insulation is chosen from among the following materials: air, glass fibre, silica wool felt.

7. Turbomachine module according to claim 5 , characterised in that the thermal inertia control device also comprises a cover plate ( 6 ) mounted on the annular arm ( 52 ) inside the shock absorbing ring ( 5 ) and a cavity ( 7 ) located between the cover plate ( 6 ) and the inner arm ( 52 ), and in that the layer of thermal insulation ( 8 , 90 ) is housed in the cavity ( 7 ).

8. Turbomachine module according to claim 7 , characterised in that the cover plate ( 6 ) comprises a single opening ( 63 ) opening up in the cavity ( 7 ).

9. Turbomachine module according to claim 7 , characterised in that the shock absorbing ring ( 5 ) also comprises a cylindrical stiffener leg ( 53 ) extending the inner annular arm ( 52 ) and in that the cover plate ( 6 ) comprises:

an upstream end ( 66 ) connected to a lower end ( 89 ) of the shock absorbing ring ( 5 ); and

a downstream end ( 67 ) connected to the cylindrical stiffener leg ( 53 ).

10. Turbomachine module according to claim 9 , characterised in that the downstream end ( 67 ) of the cover plate ( 6 ) comprises an annular tab ( 65 ) bearing on an outer face ( 56 ) of the stiffener leg ( 53 ).

11. Turbomachine module according to claim 9 , characterised in that the downstream end ( 67 ) of the cover plate ( 6 ) comprises an annular tab ( 65 ) forming a U curved towards the inside of the cavity ( 7 ), and bearing on the inner arm ( 52 ).

12. Turbomachine module according to claim 9 , characterised in that the downstream end ( 67 ) of the cover plate ( 6 ) comprises an annular tab ( 65 ) bearing on an inner face ( 55 ) of the stiffener leg ( 53 ).

13. Turbomachine module according to claim 12 , characterised in that the inner face ( 55 ) of the stiffener leg ( 53 ) forms an angle (α) with the centreline of the turbomachine ( 200 ), the value of which is between 5° and 15°.

14. Turbomachine module according to claim 12 , characterised in that it also comprises a retention clip ( 101 ) holding the annular tab ( 65 ) of the cover plate ( 6 ) on the inner face ( 55 ) of the stiffener leg ( 53 ).