Section of gondola air intake edge with electric ice protection and acoustic absorption zone

FIELD: transport.

SUBSTANCE: inventions relate to aircraft engineering, more specifically to the section of gondola air intake edge, edge of air intake for turbojet engine gondola and turbojet engine gondola. Section (7) of turbojet engine gondola (1) air intake (4) edge (4a) contains outside shell (12) and inside shell (13) as well as electric heating element (14) located between the inside shell and the outside shell and made with possibility to be connected to power supply facilities (15, 16). Herewith, the electric heating element passes through acoustic absorption zone having holes (11) which go through this section and contact with acoustic absorption device (30) attached to inside shell. In this structure, the air intake edge can be made of one or more such sections.

EFFECT: prevention of ice building on the edge of air intake with simultaneous improvement of acoustic absorbing characteristics of the edge.

12 cl, 10 dwg

The present invention relates to a partition of the edges of the air intake of the nacelle turbine engine having an outer casing, facing the outside edge, and the inner lining, facing the inside of the edge.

The thrust of the aircraft is provided by one or more power plants, which include turbojet engine housed in a cylindrical gondola. Each power unit is attached to the aircraft by a pylon, which is usually under the wing or fuselage.

The design of the gondola usually contains the air intake, located at the flow front of the engine, the middle part, covering the fan turbojet engine, and rear stream in the part that holds the device of reverse thrust and surrounds the combustion chamber of the turbojet engine, and ends, as a rule, jet nozzle, the outlet of which is located behind the turbojet engine.

The inlet contains from one side edge of the air intake is performed so that the air supplied to the fan and the internal compressors, acted in the direction of the turbojet engine is required to power its fan and the internal compressors, and on the other side of the rear flow element, to which is attached the specified edge and which both the provides proper venting in the direction of the fan blades. This entire site is attached to the flow front of the fan shroud, which is a part of the front stream side of the gondola.

In flight under certain temperature and humidity conditions, the formation of ice on the gondola at the field edge of the air inlet. In the presence of ice or frost change the aerodynamic characteristics of the air intake and disrupted the flow of air to the fan. In addition, from the edge of the air intake can sometimes separate pieces of ice that are faced with elements of the turbojet engine, in particular with the fan blades.

So you need to find any technical solutions that would help to prevent the formation of ice on the edge of the inlet.

One solution is the selection of hot air in the zone of the compressor turbojet engine and its supply to the edge of the air intake with heat its walls. However, for such a device requires a system for supplying hot air from the turbine engine to the air intake systems and exhaust hot air in the area of the edge of the air intake, which leads to undesirable increase in the weight of the power plant.

Another solution, disclosed in the patent EP 1495963, is to impose on the outer wall of the edge of the air intake special Naga is evealing resistor. This technology requires drawing on top of the de-icing heating resistor additional erosion of the protective layer.

This solution has several disadvantages. First, erosion control material does not provide the surface quality required for the exterior wall edges. Secondly, in the case of a partial coating of the edges of the air intake occurs discontinuities, which negatively affects the aerodynamics of the air intake. Finally, this system increases the total thickness of the edges, which can cause deterioration of the absorption, which is closely linked to this thickness.

However, with this system you can achieve some weight saving in comparison with a system that uses hot air taken from the turbojet engine.

To address these shortcomings in the document WO 2005/087589 was the design of the edges of the air intake of the nacelle turbine engine having an outer casing, facing the outside edge, and the inner lining, the interior edges, and characterized in that it contains at least one electric heating element made with the possibility of its connection to the means of power, and the specified heating element is located between the inner and Nar is mportant skin.

However, this solution does not consider the possibility of the presence in the section of the intake of special sound-absorbing zone, interacting with absorbent element.

The purpose of the present invention is to eliminate the above drawback, which proposed the partition of the edges of the air intake of the turbojet engine nacelle containing the outer wall facing the outside edge, and the inner lining, the interior edges, and characterized in that it comprises at least one electric heating element located between the inner and outer cladding are made with the possibility of its connection to the means of supply, and at least one heating element passes at least partially through the sound-absorbing zone in which holes passing through the said partition and in contact with the sound-absorbing element attached to the inner lining.

Thus, performing the holes passing through the entire thickness of the section of the air intake system containing anti-icing, in a sound-proof area receive a uniform perforation that meets the requirements in contacting the sound-absorbing element. In fact, unlike the prior art, when using the perforated electromagnetical the element (heater mesh or fabric), own holes which did not meet any of the sound frequencies to be absorption or appropriate sound-absorbing element, in the claimed invention the electric heating element is perforated with the section of the intake, which allows to obtain the appropriate uniform perforated through the entire thickness of sound-absorbing zones.

It should be borne in mind that in this case, when the edge of the inlet has an internal sound-absorbing element, the wall flange of the vent is in the area of sound-absorbing element of the set of acoustic holes. In the claimed invention the edges of the acoustic holes made of a rigid outer casing and pass through the wall, unlike the prior art, where they are executed in the electric heating element to pass through the wall. Thus, it is possible to maintain the high quality of the edges of the acoustic holes, while the use of external electric heating element having, usually, low hardness, would be accompanied by rather low quality of these edges.

It should be noted that in addition to the specified improve sound absorbing characteristics of the proposed solution allows to preserve the benefits of air intake device with electric heating element, built in directly the public section of the edge of the air intake of the nacelle, consisting in the fact that there is no need to apply additional protective layer, while the aerodynamic properties of the air intake will still be determined by the outer skin. In addition, the edge of the air intake may be at least partially with one or more electric heating elements, without disturbing the uniformity of the outer surface of the edge.

Preferably, the claimed section has at least one protective layer covering the heating element.

Preferably, at least one protective layer is a layer of resin.

As a variant, at least one protective layer is a glass layer.

Alternatively, the requested section contains at least two layers of at least one electric heating element separated optionally at least one metal or an organic layer.

Preferably, the requested section contains a reflective strip, next to the electric heating element and before the inner skin. The presence of such strips can reduce heat loss on the inner lining and concentrate anti-icing on the outside of the casing, which allows to optimize the energy consumption.

Preferably, the outer covering them with the em thickness less than 1 mm This allows you to optimize the heat transfer through the outer wall.

Preferably, the electric heating element is designed in the form of a metal strip forming the heating resistor.

Alternatively, heating element made in the form of fabrics, in particular organic or metal, forming a heating resistor.

Preferably, the electric heating element is designed in the form of a coil.

The claimed invention also relates also to the edge of the air intake of the nacelle turbojet engine, is made of one or more partitions, disclosed above.

The subject of the invention is also a turbojet engine nacelle containing the inlet and wherein the air inlet is equipped with a flange according to the invention.

The invention will become clearer from consideration of the following detailed description, given with reference to the attached drawings, where:

figure 1 presents a perspective view of a schematic representation of the gondola;

figure 2 on an enlarged scale shows a fragment of the edge of the air intake is made of sections according to the invention;

figure 3 presents a cross-section of the section according to the invention;

figure 4 on an enlarged scale presented in the context section according to the invention;and

figure 5 shows the fragment of the heating element in the area of sound-absorbing device;

figure 6 schematically presents one of the options part of the heating element;

7-10 presents different versions of the electric heating element.

The nacelle 1 according to the invention, as shown in figure 1, forms a cylindrical cavity for a turbojet engine (not shown)that provides the challenge that it creates air flow. This gondola 1 is located under the wing 2 to which it is attached by means of the pylon 3. It also placed the various components required for turbojet engine.

In particular, the nacelle 1 has front downstream portion forming the inlet 4, the middle part 5, containing a fan (not shown) of the turbojet engine, and back on the thread part 6, to accommodate the turbojet engine 2, which is also the system of the thrust reverser (not shown).

The inlet 4 is divided into two elements - the edge 4A, which ensures optimal absorption towards the turbojet engine of the air needed to power its fan and the internal compressors, and back flow element 4b, to which is attached the specified edge 4A and which provides adequate venting in the direction of the fan blades. This node is attached to the flow front of the fan shroud, which is a part of the middle part 5 of the gondola.

Edge 4A of the intake performed using sections 7 according to the invention, attached around the perimeter of the nacelle 1 to the back flow element 4b. Each section 7 is separated from adjacent sections by a dividing element 8, is made as one piece with the back flow element 4b.

In this particular example, the edge 4A of the intake is made of four sections 7. It is obvious that it can also be done from two sections 7 in the form of a single part or more than four sections 7.

Each section 7 contains the wall 9, the form of which is chosen in such a way as to give the edge 4A of the desired profile, and internal sound-absorbing element 30 cell type in contact with the facing toward the fan inlet area 10 wall containing a number of holes 11, is made with a uniform pitch.

The wall 10 section 7 has an outer wall 12 facing outward edge, the inner lining 13, the interior edge, and an electrical heating element 14 mounted between the inner casing 13 and the outer skin 12. The electric heating element 14 is connected with the contact output power supply, which, in turn, is connected to the cable 15 is inserted into the connector ele is Tropicana 16 on the rear section.

The wall 10 may be equipped with an electric heating element 14 only partially, depending on what areas are to be protected from icing. Thus, in figure 3 you can see that the wall 10 is equipped with electric heating element only in the area of sound-absorbing element 30 in that part of the wall that is facing toward the fan inlet. You should note that the electric heating element 14 does not reach the attachment section 7 to the back flow element 4b and remains separated from the means of connection of these structures. The fact that the attachment section 7 to the back flow element 4b is carried out usually by means of rivets (not shown), which must not come into contact with the electric heating element 14.

The electric heating element 14 is surrounded by a protective layer of resin 17, which, in turn, is surrounded by layers of glass 18, which are located on both sides of the electric heating element 14.

The outer casing 12 provides the outer airfoil edge 4A. It can be made of metal or any composite material can be preformed or be performed concurrently with the installation of the electric heating element 14. The thickness of the outer shell 12 is relatively small, which provides good heat transfer to the NRA is the t to the outside edges. The edge thickness, for example, may amount to several tenths of a millimeter.

The inner lining 13 covers the heating element 14 and completes the wall 10. As the outer casing 12, it can be made of metal or composite material may be preformed or executed during the installation of the electric heating element 14. It should be borne in mind that the inner panel 13 and the outer casing 12 can have a different thickness.

Optionally, you can add to the internal casing 12 special reflective strip (not shown), which will be located between the heating element 14 and the inner casing 13, providing a reduction of heat loss from the inner casing 13 to concentrate the heat dissipation in the direction of the outer shell 12. This will reduce the power consumption section 7 to provide the desired anti-icing.

The various layers forming the wall 10 of the structure 7, are connected to each other by means of a special bonding material such as glue or resin (not shown).

As the electric heating element 14 can be applied cut-out metal resistor, resistive organic or metallic fabric, and organic resistive foil. Especially preferred form of this element which is the shape of the coil. Of course, you must make sure that the surface electric heating element 14 allows to achieve the desired de-icing temperature.

Perform the electric heating element 14 in the form of a coil allows for greater communication between the different layers. This relationship can be improved by using the electric heating element 14 perforations or slots 20 (see Fig.6), allowing the binder material to penetrate into the perforations, thereby providing a closer interaction of different layers. We must bear in mind that if the electric heating element 14 is made together with a protective layer 17 made of resin, this node must contain a perforation 20.

The same principle perform the perforation 20 to enhance the adhesion between the layers may be applied to reflective strip.

Figure 4 illustrates the interleaving of the various layers forming the wall section.

In the field of internal sound-absorbing element 30 in the wall 10 is perforated throughout its thickness. Figure 5 shows in detail within this zone electric heating element 14.

It should be noted that the thickness of the wall 10, perforated in the area of sound-absorbing element 30, is of great importance for the acoustic properties and therefore should not exceed a certain limit value. The presence of heat is telego element 14 increases to some specified thickness. However, since the sound-absorbing device 30 is located in the direction of the air intake wall 10 in this place is less sensitive to impacts. Thus, it is possible to reduce in this area the thickness of the outer shell 12 that will allow you to compensate for this increase is due to the presence of the heating element 14.

As mentioned above, the power to the electric heating element 14 is supplied from the supply pin output is connected via a cable 15 to a power source. This contact pin passes through the inner lining 13 section 7 near the center of the latter, and is then connected to the cable 15, which in turn is connected to the power supply back flow element 4b of the air inlet 4. You should take steps to ensure that this supply pin output was protected during the manufacturing process of the wall 10 and, in particular, during the polymerization of the inner shell 13 and the outer shell 12, as well as resins in the case of organic structures made of composite material.

7-10 presents various possible configurations of the electric heating element 14. It is possible, in particular, be noted that in the device according to Fig.9 applied several is in parallel with the heating elements. As a result, in case of failure of one of these other elements will be able in order to retaliate the function of anti-icing.

You might also consider using multiple layers of electric heating elements 14, to be placed, if necessary, in accordance with various configurations.

Although the above invention has been described with reference to certain specific variants of its implementation, it should be understood that it is in no way limited to these options and covers a variety of technical equivalents are considered here, as well as various combinations thereof, provided that they do not go beyond the scope of the invention.

1. Section (7) of the edge (4A) of the inlet (4) of the nacelle (1) turbojet engine, containing the outer wall (12)facing the outside edge, and the inner lining (13), facing the inside of the flange, characterized in that it comprises at least one heating element (14)located between the inner cladding and the outer cladding are made with the possibility of connection to the means of power supply (15, 16), and at least one heating element passes at least partially through the zone of absorption, with holes (11)passing through this section and in contact with an absorbent device (30)attached to the inner lining.

2. Section (7) according to claim 1, characterized in that it contains at least the Dean of the protective layer (17, 18) surrounding the heating element (14).

3. Section (7) according to claim 2, characterized in that at least one protective layer is a resin layer (17).

4. Section (7) according to claim 2 or 3, characterized in that at least one protective layer is a glass layer (18).

5. Section (7) according to any one of claims 1 to 3, characterized in that it contains at least two layers of at least one electric heating element (14), divided optionally at least one metal or an organic layer.

6. Section (7) according to any one of claims 1 to 3, characterized in that it contains reflective strip, next to the electric heating element (14) and in front of the inner casing (13).

7. Section (7) according to any one of claims 1 to 3, characterized in that the outer casing (13) has a thickness of less than 1 mm.

8. Section (7) according to any one of claims 1 to 3, characterized in that the heating element (14) is designed as a metal strip, forming a heating resistor.

9. Section (7) according to any one of claims 1 to 3, characterized in that the heating element (14) made in the form of fabrics, in particular organic or metal, forming a heating resistor.

10. Section (7) of claim 8, wherein the heating element (14) made in the form of a coil.

11. Edge (4A) of the shroud (4) to (gondola) turbojet engine, characterized in that it is made of one or more partitions (7) according to any one of claims 1 to 10.

12. Gondola (1) turbojet engine having an air intake (4), characterized in that the air intake has an edge (4A) according to claim 11.