FR3038342A1 - TURBOMACHINE PROFILE ELEMENT HAVING AN ANTI-FRICTION AND / OR DEFROSTING SYSTEM, AND METHODS OF MANUFACTURE - Google Patents

Abstract

The invention relates to a profiled turbine engine element (1) having a body (2) comprising at least one composite material, said element (1) being characterized in that it comprises: - at least one heating resistor (4) arranged in the thickness of the body (2), at least one electrical connector (5) configured to transmit an electric current to the heating resistor (4) from at least one electrical source (7), the temperature rise induced by the passage of said electric current for anti-icing and / or defrosting of the profiled element (1). The invention also relates to methods of manufacturing the profiled element.

Description

FIELD OF THE INVENTION The invention relates to a profiled turbine engine element, comprising an anti-icing and / or de-icing system. The invention also relates to methods of manufacturing this profiled element.

BACKGROUND

In a turbomachine, certain profiled elements, such as blades, may be subject to frost formation. This depends in particular on the altitude of the aircraft and the atmospheric conditions.

However, the presence of frost degrades the performance of the turbomachine.

Therefore, it is necessary to provide a system for preventing the formation of frost on the profiled elements of the turbomachine (anti-icing) and / or remove the frost already formed (defrost).

Figure 1 is a representation of an anti-icing system of the prior art. In this Figure, hot air 100 is taken downstream of a compressor of the turbomachine, and is directed towards vanes 101 of an input rectifier of the turbomachine. The circulation of hot air prevents the formation of frost on these blades.

This solution has the disadvantage of preventing frost formation only when the turbomachine is in operation. However, when the turbomachine is stopped, such as when the aircraft is on the ground, the blades are again likely to be subject to the formation of frost.

In addition, the insertion of a hot air flow in the main vein of the turbomachine disturbs the flow, and therefore the aerodynamic performance of the turbomachine.

SUMMARY OF THE INVENTION The invention proposes a profiled turbomachine element, having a body comprising at least one composite material, said element being characterized in that it comprises at least one heating resistor disposed in the thickness of the body, at least an electrical connector configured to transmit an electric current to the heating resistor from at least one electrical source, the rise in temperature induced by the passage of said electric current for anti-icing and / or defrosting of the shaped element. The invention is advantageously completed by the following features, taken alone or in any of their technically possible combination: the heating resistor comprises at least one electrically conductive wick, in particular made of carbon material or of metallic material; the heating resistor is surrounded by an electrical insulator; the body comprises a plurality of plies comprising at least one composite material, and the heating resistor is placed between folds; the body is a woven piece comprising a plurality of weaving threads of which at least one weaving thread comprises the heating resistance; the heating resistor is surrounded by a resin, and the composite material of the body comprises: a thermosetting resin, the resin surrounding the heating resistor having a glass transition temperature greater than that of the resin of the composite material of the body, or a thermoplastic resin, the resin surrounding the heating resistor having a melting temperature higher than that of the resin of the composite material of the body. the profiled element is a blade of a turbomachine. The invention also relates to a preform for the manufacture of a profiled turbine engine element, comprising a weaving of a plurality of weaving threads, characterized in that at least one of the weaving threads comprises the heating resistance, is arranged in the thickness of the preform, and has at least one of its ends at least one electrical connector for the electrical connection to an electrical source. The invention also relates to a method of manufacturing a profiled turbine engine element, characterized in that it comprises the steps of stacking folds comprising at least one composite material so as to manufacture a body of said element, and interpose, between at least some of the plies present in the thickness of the body, at least one heating resistor having one end having at least one electrical connector configured to transmit an electric current to the heating resistor from at least one electrical source. The invention also relates to a method of manufacturing a profiled turbine engine element, characterized in that it comprises the steps of: - weaving a preform of said profiled element from a plurality of weaving threads, at least one weaving yarn comprising a heating resistor, and having, at at least one of its ends, at least one electrical connector for the electrical connection to an electrical source, said weaving being performed so as to arrange the weaving wire comprising the heating resistor in the thickness of the preform, and - manufacturing the profiled element from said preform. The invention has many advantages. The invention proposes a solution for combating the formation of icing on a profiled turbine engine element both on the ground and in flight, or de-icing said element. In particular, the solution is operational even when the turbomachine is stopped.

In addition, the solution allows to maintain good aerodynamic performance, as well as a mass and shape of satisfactory profiled elements.

Finally, the solution integrates efficiently into the process of manufacturing the profiled elements.

DESCRIPTION OF THE DRAWINGS Other characteristics, objects and advantages of the present invention will appear better on reading the detailed description which follows, and with reference to the appended drawings given by way of non-limiting examples and in which: FIG. 1 , already commented, is a schematic representation of a turbomachine according to the prior art, which has an anti-icing system; - Figure 2 is a schematic representation of an embodiment of a profiled turbomachine element according to the invention; - Figure 3 is a schematic representation of another embodiment of a profiled turbomachine element according to the invention; - Figure 4 is a representation of a heating resistor disposed on a fold comprising a reinforcement, to ensure electrical insulation; Figure 5 is an enlargement of part of Figure 4; - Figure 6 is a representation of a preform of a profiled element; - Figure 7 is a representation of a heating resistor surrounded by a sheath for providing electrical insulation; - Figure 8 is a representation of a heating resistor surrounded by a sheath in the form of ribbons, to ensure electrical insulation; - Figure 9 is a schematic representation of an embodiment of a method of manufacturing a profiled turbomachine element according to the invention; - Figure 10 is a schematic representation of another embodiment of a method of manufacturing a profiled turbomachine element according to the invention; - Figure 11 is a schematic representation of a loom for the manufacture of a preform of a profiled turbomachine element according to the invention.

DETAILED DESCRIPTION

Profiled elements

FIG. 2 shows diagrammatically an embodiment of a turbomachine profiled element 1 according to the invention. The profiled element 1 is for example, but not limited to a blade, a profiled housing element, a ferrule, a panel, radial arms, a cone, a primary and secondary flow separation spout. By way of non-limiting example, it can especially be the dawn of an input rectifier (as in a turboprop), or the blade of a rectifier in the compressor of a turbojet engine. The element 1 profile comprises a body 2. The body 2 is made of one or more materials comprising at least one composite material.

In the example of Figure 2, the body 2 comprises a leading edge 13 and a trailing edge 14. As shown in FIG.

As shown in FIG. 2, the profiled element 1 comprises at least one heating resistor 4. The heating resistor 4 is disposed in the thickness of the body 2. The resistor 4 is a resistor or an electrical conductor, for which the passage of an electric current induces a rise in temperature, in particular by Joule effect. The shaped element 1 further comprises at least one electrical connector 5 configured to transmit an electric current to the heating resistor 4 from at least one electrical source 7. For this purpose, the ends of the heating resistor 4 are connected to the electrical connector 5. Figure 2 takes as an example element 1 profiled a variable-pitch blade of a stator of a turbomachine. In this case, the connector 5 may in particular be arranged in a pivot 23 of the blade.

The electrical connector typically includes a positive terminal and a negative terminal for connection to the electrical source. The electrical source 7 is for example a pre-existing source of the turbomachine or the aircraft, such as the auxiliary power unit, or a new electrical source specifically installed for the purposes of anti-icing and / or deicing of the element. 1 profile.

As it is understood, the passage of the electric current in the resistor 4 induces a rise in temperature of said resistor, and consequently of the external surfaces of the profiled element 1, which allows anti-icing and / or de-icing of the element 1 profile. Anti-icing is the action of preventing the formation of frost, and deicing the action of removing existing frost.

The heating resistor 4 is deployed inside the body 2 of the profiled element 1 in order to cover the surfaces of the profiled element 1 which are liable to be subjected to the presence of frost, to the underside and / or on the upper surface of the element 1. Indeed, the surfaces located on the outer part of the profiled element 1 and disposed in line with the heating resistor 4 undergo a rise in temperature for anti-icing and / or defrosting.

The surfaces concerned are typically, but not exclusively, the leading edge, the trailing edge, the center of the blade, and the platforms.

Alternatively, the heating resistor 4 can be deployed so as to heat the entire external surface of the body 2.

In an exemplary embodiment, the electric source 7 is a direct current source. The power delivered is typically from ten to several hundred Watts depending on the dimensions of the profiled element 1 and the atmospheric conditions. In general, the power is calibrated to achieve a surface temperature of the profiled element 1 greater than 10 ° C. These values are not, however, limiting.

Note that the electrical source 7 may itself be controlled by a processing unit comprising a memory and a processor, the processing unit controlling the electrical source 7 according to a predefined program stored in the memory, and / or following orders from an operator (pilot, maintenance operator or other).

In the case of a program stored in the memory of the processing unit, it is advantageous for it to receive in particular input parameters of the flight recorded by sensors of the aircraft (temperature, pressure, altitude, etc.). ), and calculates accordingly the electric power required for the electric source 7.

As can be understood, the profiled element 1 is protected against frost formation even if the turbomachine is stopped, since the availability of the electric source 7 does not necessarily depend on the operation of the turbomachine.

In Figure 3, there is shown another example of element 1 turbomachine profile, in this case a fixed blade of a rectifier. In this example, the electrical connector 5 is housed in a platform 25 of the blade. The heating resistor 4 is preferably arranged on the side of the leading edge 13.

The heating resistor 4 may in particular comprise an electrically conducting wick, such as a unidirectional carbon wick, or a steel or copper wick. Other materials, whose electrical resistivity is compatible with the intended application and installation in composite materials, can be used.

According to the manufacturing method of the profiled element 1, and as explained below, the heating resistor 4 may have a positioning in the body 2 which differs.

In one embodiment, the body 2 comprises a plurality of plies 10 comprising at least one composite material. This embodiment is illustrated in FIGS. 4 and 5. A composite ply generally comprises a resin and a fibrous reinforcement (such as glass or kevlar). In FIGS. 4 and 5, the fiber reinforcement is made of glass, which also makes it possible to provide electrical insulation for the heating resistor 4.

In this case, the heating resistor 4 is arranged between folds 10.

In another embodiment, the body 2 is a woven piece having a plurality of weaving threads 12 (see Figure 6, which illustrates the preform 16 for obtaining the body 2). The yarns 12 of weaving comprise weaving son constituting the reinforcement of a composite material.

In this case, at least one weaving thread comprises the heating resistor 4.

As illustrated in Figure 6 schematically, the preform 16 comprises a weaving of a plurality of yarns 12 of weaving (for example carbon, or ceramic). These weaving threads are the reinforcement of a composite material.

At least one of the weaving threads 12 comprises the heating resistance element 4 and is placed in the thickness of the preform 16. The weaving thread 12 comprising the resistance element 4 has at least one of its ends 20 at least one electrical connector 5 for the electrical connection to the electric source 7.

The manufacture of the element 1 profiled from this preform 16 will be explained later.

In order to electrically isolate the heating resistor 4 from the rest of the element, the latter may in particular be surrounded by an electrical insulator 9.

Various electrical insulators can be used. In the case of a metal resistor 4, the following resins may for example be used: epoxides, cyanates-ester (CE), polyimides, benzoaxines (BOX), bismaleimides (BMI).

There is shown in Figure 7 a heating resistor 4 surrounded by a sheath 9. This is for example a sheath comprising a continuous glass fiber.

In Figure 8, there is shown a heating resistor 4 surrounded by a sheath 9 in the form of portions. These are, for example, portions (ribbons) of glass fibers.

The fiberglass may in particular be used in addition to a resin surrounding the heating resistor 4, in order to improve the electrical insulation.

In one embodiment, the heating resistor 4 is surrounded by an insulating resin, and the composite material of the body 2 comprises a thermosetting or thermoplastic resin.

In order to optimize the costs and the performances, in the case of a thermosetting resin, it is advantageous for the resin surrounding the heating resistor 4 to have a glass transition temperature greater than that of the resin of the composite material of the body 2. even in the case of a thermoplastic resin, it is advantageous that the resin surrounding the heating resistor 4 has a higher melting point than the resin of the composite material of the body 2.

Indeed, in order to obtain a given temperature on the surface of the profiled element 1, it is necessary to heat the resistor 4 to a higher temperature, because of the heat losses. Therefore, the resistor 4 must be able to withstand higher temperatures. As can be understood, the cost of the resin increases with its glass transition temperature (or, if appropriate, melting point). The choice of different resins and adapted to the temperature needs thus makes it possible to optimize the performances while reducing the costs.

In a nonlimiting example, the insulation of the heating resistor 4 comprises cyanate ester (whose glass transition temperature is of the order of 300 ° C.), while the composite material of the body 2 is impregnated with a resin epoxide (whose glass transition temperature is of the order of 180 ° C).

Manufacturing processes

In one embodiment, the method of manufacturing the turbomachine profiled element 1 comprises the following steps.

In a step E1, folds 10 comprising at least one composite material are stacked so as to produce a body 2 of said element 1. The folds 10 are assembled by gluing. The bonding is generally carried out by heating the resin impregnating the fibrous reinforcements of the folds 10.

The method comprises a step E2 consisting in interposing, between at least some of the plies 10 present in the thickness of the body 2, at least one heating resistor 4 as described above, and one end of which has at least one electrical connector. As indicated previously, the electrical connector 5 is intended to transmit an electric current to the heating resistor 4 from at least one electric source 7. At the end of the process, the body 2 comprises the heating resistor 4 in its thickness. The connector 5 is in turn in a housing adapted to the body 2 (as a foot or a platform).

In another embodiment, shown diagrammatically in FIG. 10, the element 1 of a turbomachine section is manufactured by a weaving process.

The method comprises a step S1 of weaving a preform 16 of said profiled element 1.

The weaving of the preform is carried out using yarns 12 of weaving distributed in warp yarns and weft yarns.

In particular, a loom Jacquard type can be used to weave the preform in three dimensions.

FIG. 11 diagrammatically shows a Jacquard loom 27 on which are mounted warp threads, which are oriented in the longitudinal direction (arrow x), and which extend over several superimposed layers in the vertical direction (arrow z), and weft yarns oriented in the transverse direction (arrow y).

The weaving of the preform is here made with a plurality of threads 12 of weaving. These yarns 12 of weaving comprise weaving son constituting the reinforcement of a composite material.

At least one weaving wire comprises a heating resistor 4, or consists of this heating resistor 4. In other words, the heating resistor 4 is part, from the design of the preform 16, the weaving of the preform, which is very advantageous. This weaving wire, which carries the heating resistor 4, has, at at least one of its ends 20, at least one electrical connector 5 for the electrical connection to an electric source 7.

The weaving is performed so as to arrange the weaving wire comprising the heating resistor 4 in the thickness of the preform 16, which will constitute the thickness of the body 2 of the profiled element 1.

The method then comprises step S2 consisting of manufacturing the profiled element 1 from said preform 16.

The manufacturing comprises a cutting step, in which the preform 16 is cut according to the shape and dimensions of the constituent parts of the profiled element 1.

The preform 16 is then placed in a mold. A binder comprising a thermosetting resin is then injected into the mold to impregnate the entire preform. After heating the mold, the molded piece is out of the mold, and provides the desired element 1 profile.

Claims (10)

1. Element (1) turbomachine section, having a body (2) comprising at least one composite material, said element (1) being characterized in that it comprises: - at least one heating resistor (4) arranged in the body thickness (2), - at least one electrical connector (5) configured to transmit an electric current to the heating resistor (4) from at least one electrical source (7), the temperature rise induced by the passage of said current electric allowing an anti-icing and / or defrosting of the element (1) profiled. 2. Element (1) section according to claim 1, wherein the heating resistor (4) comprises at least one electrically conductive wick, made of carbon material or metal material. 3. Element (1) profiled according to one of claims 1 or 2, wherein the heating resistor (4) is surrounded by an insulator (9) electric. 4. Element (1) profiled according to one of claims 1 to 3, wherein: - the body (2) comprises a plurality of plies (10) comprising at least one composite material, and - the heating resistor (4) is disposed between folds (10). 5. Element (1) profiled according to one of claims 1 to 3, wherein: - the body (2) is a woven piece having a plurality of yarns (12) weaving which at least one weaving thread comprises the resistance (4) heating. 6. Element (1) profiled according to one of claims 1 to 5, wherein: - the heating resistor (4) is surrounded by a resin, and - the composite material of the body (2) comprises o a thermosetting resin, the resin surrounding the heating resistor (4) having a glass transition temperature greater than that of the resin of the composite material of the body (2), or o a thermoplastic resin, the resin surrounding the heating resistor (4) having a temperature of melting higher than that of the resin of the composite material of the body (2). 7. element (1) profiled according to one of claims 1 to 6, said element (1) being a blade of a turbomachine. 8. Preform (16) for the manufacture of a member (1) turbomachine section according to one of claims 1 to 3 or 5, or according to one of claims 6 or 7, when they depend on claims 1 at 3 or 5, comprising a weave of a plurality of yarns (12) for weaving, characterized in that at least one of the yarns (12) of weaving: - comprises the resistor (4) heating, - is arranged in the the thickness of the preform (16), and - has at least one of its ends (20) at least one electrical connector (5) for the electrical connection to an electric source (7). 9. A method of manufacturing a member (1) profiled turbomachine, characterized in that it comprises the steps of: - stack (E1) folds (10) comprising at least one composite material so as to produce a body (2) of said element (1), and - interposing (E2) between at least some of the plies (10) present in the thickness of the body (2), at least one heating resistor (4) having at least one end an electrical connector (5) configured to transmit an electric current to the heating resistor (4) from at least one electrical source (7). 10. A method of manufacturing a member (1) profiled turbomachine, characterized in that it comprises the steps of: - weaving (S1) a preform (16) of said element (1) profiled from: o d ' a plurality of yarns (12) for weaving, at least one weaving thread comprising a heating resistor (4), and having, at at least one of its ends (20), at least one electrical connector (5) for the electrical connection an electric source (7), said weaving being arranged to arrange the weaving wire comprising the heating resistor (4) in the thickness of the preform (16), and - to manufacture (S2) the element (1) profile from said preform (16).