Abradable device on the blower casing of a gas turbine engine

Abstract

The invention concerns a turbine engine with an axis of rotation B comprising a blower casing ( 10 ) and a blower (V) with movable blades ( 17 ). A clearance lies between the internal surface of the casing and the free ends of the blades. A bearing of the blower is connected to fixed parts of the turbine engine by connections such that, in the event of a load on the blower blades, these connections break and the axis of rotation of the blower oscillates about the axis of rotation B. The casing comprises, bonded to its internal surface and over at least part of the extent of the clearance, a layer of thermoformable foam ( 19 ) placed opposite the ends of the blades ( 17 ) of the blower (V). The layer of thermoformable foam ( 19 ) is partly covered with a layer of abradable substance ( 14 ), the thickness of the layer of abradable substance ( 14 ) is such that the free ends of the blades of the blower do not reach the layer of foam during the normal functioning of the turbine engine, and, in the event of a load on the blower, the free ends of the blades at least partly fragment the layer of abradable substance.

1 . Turbine engine with an axis of rotation B comprising a blower casing ( 10 ) and a blower (V) with movable blades ( 17 ), a clearance lying between the internal surface of the casing and the free ends of the blades, a bearing of the blower being connected to fixed parts of the turbine engine by connections such that, in the event of a load on the blower blades, these connections break and the axis of rotation of the blower oscillates about the axis of rotation B, wherein the casing comprises, bonded to its internal surface and over at least part of the extent of the clearance, a layer of thermoformable foam ( 19 ) placed opposite the ends of the blades ( 17 ) of the blower (V), the layer of thermoformable foam ( 19 ) being partly covered with a layer of abradable substance ( 14 ), the thickness of the layer of abradable substance ( 14 ) being such that the free ends of the blades of the blower do not reach the layer of foam during the normal functioning of the turbine engine, and, in the event of a load on the blower, the free ends of the blades at least partly fragment all the layers of abradable material ( 14 ) and thermoformable foam ( 19 ).  
   
   
       2 . Turbine engine according to  claim 1 , wherein the thickness of the layer of foam and of the layer of abradable substance is such that there exists a clearance remaining between the free ends of the blades of the blower and the layer of abradable substance during normal functioning of the engine, this remaining clearance being sufficiently small to limit the passage of air in order to preserve a dynamic flow of air whose path is forced by the blades of the blower.  
   
   
       3 . Turbine engine according to  claim 1 , wherein the layer of thermoformable foam consists of preformed sectors.  
   
   
       4 . Turbine engine according to  claim 1 , wherein the layer of thermoformable foam is a layer of polyacrylic imide foam.  
   
   
       5 . Turbine engine according to  claim 1 , wherein the layer of abradable substance is made from epoxy resin filled with glass balls.  
   
   
       6 . Turbine engine according to  claim 1 , wherein the layer of abradable substance is made from silicone filled with glass balls.  
   
   
       7 . Turbine engine according to  claim 1 , wherein the layer of abradable substance adheres directly or indirectly to the layer of thermoformable foam.  
   
   
       8 . Blower casing able to form part of a turbine engine according to  claim 1 , the casing comprising, bonded to its internal surface, a layer of thermoformable foam intended to be placed opposite free ends of the blades ( 17 ) of the blower (V), the layer of thermoformable foam being partly covered with a layer of abradable substance, the thickness of the layer of abradable substance being such that the free ends of the blades of the blower do not reach the layer of foam during the normal functioning of the turbine engine, and, in the event of a load on the blower, the ends of the blades at least partly fragment all the layers of abradable material and thermoformable foam.