Ring-shaped thermomechanical part for turbine engine

Abstract

A ring-shaped thermomechanical part for a turbine engine, comprising at least one coating including a polymeric matrix and fillers in non-deflagrating carbon exclusively comprising the chemical element C. A turbine engine comprising such a part.

Claims

1. A turbine engine comprising a ring-shaped thermomechanical part for a turbine engine, the ring-shaped thermomechanical part comprising at least one coating including a polymeric matrix and fillers, wherein the fillers are exclusively non-deflagrating carbon fillers comprising the chemical element C, and wherein the fillers are in the form of round particles, acicular particles, fibers, mat, fabric, or foam.

2. The turbine engine according to claim 1, wherein the carbon has a self-inflammation temperature above 1,900° C.

3. The turbine engine according to claim 1, wherein the fillers are in carbon black.

4. The turbine engine according to claim 1, wherein the polymeric matrix mainly comprises a polysiloxane.

5. The turbine engine according to claim 1, wherein a mass content of the fillers in the thermomechanical part is at least 50%.

6. The turbine engine according to claim 1, wherein the fillers are in the form of round particles, acicular particles, mat, fabric, or foam.

7. A turbine engine stage comprising a casing and a rotor configured so as to rotate inside the casing, the stage further comprising a thermomechanical part placed on the casing and radially located between the rotor and the casing, wherein the thermomechanical part comprises at least one coating including a polymeric matrix and fillers, wherein the fillers are exclusively non-deflagrating carbon fillers comprising the chemical element C, and wherein the fillers are in the form of round particles, acicular particles, fibers, mat, fabric or foam.

8. A turbine engine comprising a turbine engine stage according to claim 7.

9. A turbine engine stage comprising a casing and a stator part mounted in the casing, the stage further comprising a thermomechanical part comprising at least one coating including a polymeric matrix and non-deflagrating carbon fillers exclusively comprising the chemical element C, wherein the thermomechanical part is placed on the casing and used as a sealing material for joining the casing and the stator part.

10. The turbine engine stage according to claim 9, wherein a mass content of the fillers in the thermomechanical part is less than or equal to 50%.

11. The turbine engine stage according to claim 9, wherein a mass content of the fillers in the thermomechanical part is at least 50%.

12. The turbine engine according to claim 9, wherein the fillers are in the form of round particles, acicular particles, mat, fabric, or foam.

Description

SHORT DESCRIPTION OF THE DRAWINGS

(1) The inventions and advantages thereof will be better understood upon reading the detailed description which follows, of embodiments of the invention given as non-limiting examples. This description makes reference to the appended drawings, wherein:

(2) FIG. 1, already described, is a partial sectional view of a turbine engine of the state of the art, comprising abradable coatings and sealing materials;

(3) FIG. 2 is a partial sectional view of a turbine engine comprising thermomechanical parts according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 2 is a view similar to that of FIG. 1 already described. The elements corresponding to or identical with those of the state of the art will receive the same reference symbol, to within the figure of hundreds, and will not be described again.

(5) The turbine engine 50 illustrated in FIG. 2 comprises a plurality of thermomechanical parts 10, used equally as an abradable material or as a sealing material. The thermomechanical parts 10 are ring shaped in this example.

(6) As indicated earlier, the thermomechanical parts 10 comprise at least one coating including a polymeric matrix and non-deflagrating carbon fillers.

(7) In this embodiment, the polymeric matrix mainly comprises at least one polysiloxane, more particularly here a silicone resin, preferably a bulk cross-linking two-component silicone resin at room temperature and at a temperature.

(8) Moreover, the fillers here are in the form of carbon fibers and more particularly of short fibers, i.e. of a larger size comprised between about 5 mm and 10 mm. In this embodiment, the mass level of fillers in the matrix has the value of about 70%. As indicated earlier, a mass level of fillers of about 50% or more is favorable for the use of the thermomechanical part as an abradable material.

(9) The higher the mass level of fillers in non-deflagrating carbon, the less the abraded material circulating in the turbine engine will be able to undergo self-inflammation.

(10) When the thermomechanical part 10 is intended to be used exclusively as an abradable material, the fillers will preferentially be in the form of a powder of an indifferent form. Conversely, when the thermomechanical part 10 is intended to be used as an abradable part or as a sealing material, the use of fillers as fibers, particularly as long fibers, improves the mechanical strength of the coating.

(11) After abrasion of the thermomechanical parts 10 by the moving blades 50 or to a lesser extent by the wipers 62, the material removed by abrasion (matrix and fillers) is removed as dust. More specifically, the material removed by the fan blades 52 is discharged into the flow path 54. The material removed by the compressor blades 58 is discharged towards the combustion chamber. The material removed by the wipers 62 is discharged by the air flow and directed towards the counter-pressure chambers. Further, as the fillers are in non-deflagrating carbon, this dust does not soften, does not adhere to the walls of the turbine engine, does not ignite and does not generate aggregates which may clog the ventilation channels of the turbine engine.

(12) A test for self-inflammation of carbon in a Hartmann tube will now be described. In a Hartmann tube, an electric spark is generated between two electrodes within a cloud of carbon dusts lifted by an air jet and it is noted whether an inflammation occurs or not. In the apparatus used, the maximum energy which may be used for the spark is 1,200 megajoules (MJ).

(13) The minimum inflammation energy (MIE) of the carbon, here as a dust, is measured. The MIE of a dust is defined by the international standard IEC 1241-2-3 as being comprised between the strongest energy E1 at which inflammation does not occur during at least 20 successive tests for attempting to inflame a dust/air mixture and the lowest energy E2 at which inflammation occurs during 20 successive tests. The energy is, in the present case, provided by an electric spark.

(14) In this case, it is seen that during 20 successive tests with a spark of 1,200 MJ, the carbon does not ignite. Therefore, the carbon has a minimum inflammation energy (MIE) strictly greater than 1,200 megajoules (MJ).

(15) A method for coating a ring-shaped thermomechanical part for a turbine engine will now be described. Such a method may comprise the following steps: providing a polymeric matrix; loading the matrix with non-deflagrating carbon fillers; applying the loaded matrix on the part.

(16) The application step results in that the part comprises at least one coating including a polymeric matrix and fillers in non-deflagrating carbon.

(17) It is preferable that the coating method be applied under a protected atmosphere, so as not to contaminate the non-deflagrating carbon used for loading the matrix.

(18) The step of loading the matrix with said fillers may comprise mixing the loaded matrix, for example by means of a static or dynamic mixer, in order to ensure homogeneity thereof. Moreover, the step of loading the matrix may comprise extracting the air bubbles from the loaded matrix. If applicable, this extraction of bubbles is preferably provided after the mixing with mixer.

(19) The step of loading the matrix with non-deflagrating carbon fillers may be carried out manually, by injection, with the method known to one skilled in the art as <<Resin Transfer Molding>> (RTM), or by infusion. The manual application, the injection and the RTM method may be used for directly applying the coating of a loaded matrix onto the part. Infusion may be used for impregnating with a polymeric matrix a preform in non-deflagrating carbon (notably fibers or a fabric), which preform should then be added onto the part, for example by adhesive bonding.

(20) The embodiment described with reference to FIG. 2 is such that the entire part is formed with the single coating. In other embodiments, the thermomechanical part may comprise a support on which the coating is applied.

(21) The embodiment described with reference to FIG. 2 is such that the same coating is used as an abradable material and as a sealing material. However, depending on the different uses, it is possible to provide different coatings, for example coatings having different mass filler levels and/or different filler shapes.

(22) Although the present invention has been described with reference to specific exemplary embodiments, modifications may be provided to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the different illustrated/mentioned embodiments may be combined in additional embodiments. Therefore, the description and the drawings have to be considered in an illustrative sense rather than a restrictive sense.