AIRCRAFT PROPULSION SYSTEM COMPRISING A PIPING CIRCUIT THAT IS AT LEAST PARTIALLY VENTILATED

Abstract

AIRCRAFT PROPULSION SYSTEM COMPRISING A PIPING CIRCUIT AT LEAST PARTIALLY VENTILATED. The invention relates to a propulsion system (100) comprising: a fuel tank (520); a turbojet engine (102) comprising an engine and a fan blowing an airflow (F); a piping circuit (20) comprising a single-wall duct (21) extending from the tank and a second piping portion (23) comprising two double-wall ducts (230a, 230b) fluidly connecting the single-wall duct and a connection interface with the engine. The second portion also comprises a second connector (24) disposed between the two double-wall ducts and an air supply duct (25) fluidly connecting the fan and the double-wall ducts so as to draw a portion (F1) of the airflow (F) from the fan into the double-wall ducts and cool the latter. Fig. 3

Description

Title of the invention: AIRCRAFT PROPULSION SYSTEM COMPRISING A PIPING CIRCUIT AT LEAST PARTIALLY VENTILATED technical field

[0001] The present invention relates to an aircraft propulsion system comprising a piping circuit that is at least partially ventilated, and to an aircraft comprising such a propulsion system. PREVIOUS STATE OF THE ART

[0002] As illustrated in [Fig.1], an aircraft 50 comprises a fuselage 51 and a wing 52 on each side of the fuselage 51. At least one propulsion system 100 is fixed under each wing 52 and comprises a turbojet 102 which is fixed to the wing 52 by a jet engine pylon 104.

[0003] By convention, X designates the longitudinal axis of the propulsion system 100 corresponding to a longitudinal axis X of the turbojet 102. Furthermore, Y designates the transverse axis of the system 100 corresponding to a transverse axis of the turbojet 102, this axis being horizontal when the aircraft is on the ground, and Z designates the vertical axis or vertical height of the propulsion system 100 corresponding to a vertical axis of the turbojet 102, this axis being vertical when the aircraft is on the ground, these three axes X, Y and Z being mutually orthogonal.

[0004] Furthermore, the terms "front" and "rear" are to be considered in relation to a forward direction of movement of the aircraft when the turbojet 102 is in operation, this direction being schematically represented by arrow 107. The turbojet 102 also has a vertical median plane XZ passing through the longitudinal axis X and the vertical axis Z.

[0005] The turbojet 102 has at the front, a fan casing 102a surrounding a tubular fan duct in which a fan rotates and, at the rear of the fan casing 102a, a smaller central casing 102b, enclosing the core of the turbojet 102. The fan casing 102a and the central casing 102b extend globally coaxially around the longitudinal axis X.

[0006] Fig. 2 shows a propulsion system 100 according to the prior art, with the turbojet 102 and the engine mast 104 by which the turbojet 102 is fixed to the wing 52. The engine mast 104 is represented here by its primary structure 106 which is fixed under the wing 52.

[0007] The primary structure 106 extends along the longitudinal axis X between a front end and a rear end and takes the form of a box girder which includes a longitudinal member lower 106a, an upper spar 106b, two side panels (not shown) connecting the two spars and internal ribs 106c distributed along the box 106.

[0008] The turbojet 102 is fixed under the engine mast 104 by means of engine attachments which conventionally include, at the front, a front engine attachment 107a, at the rear, a rear engine attachment 107b, and between the front and rear engine attachments, a thrust force recovery assembly comprising recovery rods 107c fixed between the turbojet 102 and the box 106, to absorb the thrust forces generated by the turbojet 102.

[0009] The reactor tower 104 also includes a secondary structure 108 which is located at the front end of the box 106 and below the lower spar 106a. This secondary structure is situated directly opposite the fan casing 102a. In other words, the secondary structure 108 of the reactor tower 104 is located below the box 106 and at the rear of the fan.

[0010] As illustrated in hatching on [Fig.2], the first zone 110 located between the lower spar 106a, the secondary structure 108 and the central casing 102b of the turbojet engine, is exposed to very high temperatures and this first zone 110 therefore constitutes an area of ​​significant fire risk.

[0011] The second zone 111, located within the box 106 and under the fairings of the engine pylon 104, contains numerous pieces of equipment, including supply and drain lines for fluids necessary for the operation of the turbojet engine 102. In particular, fuel supply lines extend between the tank (generally located in the wing 52) and the engine of the turbojet engine 102. Similarly, fuel drain lines, for example in the event of a fuel leak, extend into the second zone 111.

[0012] In order to ensure optimal safety and operation of these ducts (particularly with regard to high temperatures in zone 111), it is necessary to ventilate the second zone 111 in order to maintain a lower temperature there than in the first zone 110.

[0013] One drawback of this solution is that the second zone 111 to be cooled is large and requires significant ventilation. Furthermore, due to the large size of the second zone 111 to be ventilated, it is relatively difficult to control its temperature locally. In particular, it is difficult to ensure that critical equipment (such as fuel lines, for example) is in an environment with an optimal temperature.

[0014] Thus, there is a need to provide optimal thermal protection for the fuel lines of an aircraft propulsion system which addresses at least some of these drawbacks. Description of the invention

[0015] An object of the present invention is to propose an aircraft propulsion system offering a thermal protection solution for fuel transport conduits at the level of the reactor mast box.

[0016] To this end, an aircraft propulsion system is proposed comprising: - a tank intended to contain fuel and to be placed in a wing of said aircraft, said tank comprising a first connection interface; - a turbojet engine comprising: • an engine having a second connection interface; and • a blower intended to blow an airflow from the front to the rear of the aircraft, a third connection interface being disposed in the airflow downstream of the blower; - a piping circuit comprising a first connector and a single-wall conduit extending between said first connection interface of said tank and said first connector, and a second section of piping comprising: • a second connector arranged between said first connector and said second interface of said motor; • a first double-walled conduit extending between said first connector and said second connector; • a second double-walled conduit extending between said second connector and said second interface of said motor.

[0017] In particular, said first and second double-walled conduits each comprise a central conduit defining a central channel through which said fuel flows, and a peripheral conduit extending around said central conduit and defining, together with said central conduit, a peripheral channel. Said second connector ensures fluid continuity between the central channels of the first and second double-walled conduits and fluid continuity between the peripheral channels of the first and second double-walled conduits. Said second connector comprises an inlet orifice opening into said peripheral channel of the first double-walled conduit or the second double-walled conduit.

[0018] According to the invention, said piping circuit further comprises an air supply duct fluidly connecting said third connection interface of the blower and said inlet orifice so as to allow a portion of said airflow from the blower to enter said peripheral channels of the first and second double-walled ducts.

[0019] In this way, the invention proposes a simple solution for ventilating, and thus cooling, the central channel of a double-walled duct carrying fuel between the tank located in the aircraft wing and the engine located in the turbojet. Air is therefore continuously supplied to the peripheral channel when the turbojet is operating, so that the central channel of the double-walled ducts is cooled.

[0020] Advantageously, said second connector comprises: - a first plate and a second plate receiving respectively a first end of said first double-walled conduit and a first end of said second double-walled conduit; - a first sealing washer placed between the said first and second plates.

[0021] In particular, one of said plates comprises said inlet orifice. Each of said plates and said first washer comprises a central bore, said central bores enabling fluid connection of said central channels of said first and second double-walled conduits. Said first plate comprises a plurality of first holes opening into the peripheral channel of said first double-walled conduit, where said second plate comprises, for each first hole, a second hole opening into the peripheral channel of said second double-walled conduit, where said first washer comprises, for each first hole, a third hole fluidly connecting the associated first and second holes.

[0022] According to a particular aspect of the invention, said central and peripheral conduits of said first double-walled conduit are fixed to said first plate by welding and said central and peripheral conduits of said second double-walled conduit are fixed to said second plate by welding.

[0023] According to another particular aspect of the invention, said second connector comprises first clamping means configured to clamp said first and second plates towards each other.

[0024] According to a particular aspect of the invention, said first connector comprises: - a third plate receiving a first end of said single-wall duct and a fourth plate receiving a second end of said first double-wall duct; - a second sealing washer positioned between the said third and fourth plates.

[0025] In particular, said fourth plate has a drain opening into said peripheral channel of said first double-walled conduit and fluidly connecting said peripheral channel of said first double-walled conduit to the outside of said piping circuit. Said third and fourth plates and said second washer each have a central bore, said central bores fluidly connecting said central channel of said first double-walled conduit and said single-walled conduit.

[0026] According to another particular aspect of the invention, said single-wall conduit is fixed to said third plate by welding and said central and peripheral conduits of said first double-wall conduit are fixed to said fourth plate by welding.

[0027] According to yet another particular aspect of the invention, said first connector comprises second clamping means configured to clamp said third and fourth plates towards each other.

[0028] According to a particular aspect of the invention, said second interface comprises a fifth plate receiving a second end of said second double-walled conduit, said fifth plate comprising: - a central bore extending coaxially and being fluidly connected to said central conduit of said second double-walled conduit, said central bore being further intended to be fluidly connected to a fuel supply circuit of said engine; - a discharge orifice fluidly connecting said peripheral channel of said second double-walled conduit to the outside of said piping circuit.

[0029] The invention also relates to an aircraft comprising a propulsion system as described above and a reactor mast box, said box forming a primary structure and comprising a lower spar, said propulsion system being fixed to said lower spar.

[0030] According to a particular aspect of the invention, said single-skin duct extends above said box and said first double-skin duct and / or said second double-skin duct pass through said box at the level of at least one opening.

[0031] According to another particular aspect of the invention, each opening includes a sealing joint configured to ensure sealing between said box and said first double-walled duct or said second double-walled duct passing through said opening.

[0032] According to a particular aspect of the invention, the aircraft further comprises a secondary structure fixed below said box and behind said blower, said second interface comprising third fastening means configured to fix said second interface to said secondary structure. Brief description of the drawings

[0033] The features of the invention mentioned above, as well as others, will become clearer upon reading the following description of an exemplary embodiment, said description being made in relation to the accompanying drawings, among which:

[0034] [Fig-1] is a side view of an aircraft;

[0035] [Fig.2] is a side and cross-sectional view of a propulsion system according to art previous;

[0036] [Fig.3] is a side and cross-sectional view of a propulsion system according to the invention;

[0037] [Fig.4] a perspective and cross-sectional view of a first connector of the piping circuit according to the invention;

[0038] [Fig.5] a perspective and cross-sectional view of a second connector of the piping circuit according to the invention;

[0039] [Fig. 6] a perspective and cross-sectional view of a connection interface for the piping circuit according to the invention; and

[0040] [Fig.7] a perspective and cross-sectional view of a junction between the aircraft box and the piping circuit according to the invention.

[0041] DETAILED DESCRIPTION OF TWO EXAMPLES OF IMPLEMENTATION

[0042] Fig. 1 illustrates an aircraft 50 according to the invention which comprises a fuselage 51 and a wing 52 on each side of the fuselage 51. At least one propulsion system 100 is fixed under each wing 52 and comprises a turbojet 102 fixed to the wing 52 by a jet pylon 104.

[0043] The turbojet 102 comprises, at the front, a fan casing 102a surrounding a tubular fan duct in which rotates a fan intended to blow an airflow F from outside the aircraft 50 from the front to the rear of the aircraft 50 and, at the rear of the fan casing 102a, a smaller central casing 102b, enclosing the turbojet engine 102. The fan casing 102a and the central casing 102b extend globally coaxially around the longitudinal axis X.

[0044] Fig. 3 shows the propulsion system 100 with the turbojet 102 and the engine pylon 104 by which the turbojet 102 is attached to the wing 52. The engine pylon 104 is represented here by its primary structure 106 which is attached under the wing 52.

[0045] The primary structure 106 extends along the longitudinal axis X between a front end and a rear end and takes the form of a box 106 which includes a lower spar 106a, an upper spar 106b, two side panels (not shown) connecting the two spars and internal ribs 106c distributed along the box 106.

[0046] The reactor mast 104 also includes a secondary structure 108 which is located at the forward end of the caisson 106. More specifically, the secondary structure 108 is fixed below box 106 and at the rear of the blower.

[0047] Figure 3 illustrates an example of a propulsion system 100 (hereinafter referred to as the "system") according to the invention. Figures 4 to 7 illustrate details of this system 100.

[0048] More specifically, the aircraft propulsion system 100 comprises a fuel tank 520 for use in a wing 52 of the aircraft 50. The fuel tank 520, which is located above the wing box 106, has a first connection interface 521. The system 100 also comprises a turbojet engine 102, which has an engine with a second connection interface 26 and, as described previously, a fan for blowing an airflow F from the front to the rear of the aircraft 50. The system 100 further comprises a third connection interface 103c, which is located in the airflow downstream of the fan so as to receive the airflow F. In this example, the third connection interface 103c is fixed to a wall of the fan housing 102a.

[0049] The system 100 further includes a piping circuit 20 which, among other things, supplies the engine with fuel. The circuit 20 includes a first connector 22 (described in detail later in the description) and a single-wall conduit 21 extending between the first connection interface 521 of the tank 520 and the first connector 22. In other words, the single-wall conduit is connected to the tank 520 via the first connection interface 521 so as to transport fuel from the tank 520.

[0050] Circuit 20 further comprises a second section 23 of piping which includes: - a second connector 24 positioned between the first connector 22 and the second interface 26 of the motor; - a first double-walled 230a conduit extending between the first connector 22 and the second connector 24; and - a second double-walled 230b conduit which extends between the second connector 24 and the second interface 26 of the motor.

[0051] As illustrated in [Fig. 5], which shows the second connector 24 in detail, the first 230a and second 230b double-walled conduits each have a central conduit 231 defining a central channel 231a through which the fuel flows, and a peripheral conduit 232 extending around the central conduit 231 and defining, together with the central conduit 231, a peripheral channel 232a. The second connector 24 ensures fluid continuity between the central channels 231a of the first 230a and second 230b double-walled conduits and fluid continuity between the peripheral channels 232a of the first 230a and second 230b double-walled conduits.

[0052] According to the invention, the second connector 24 has an inlet port 241 which opens into the peripheral channel 232a of the first double-walled duct 230a (as illustrated in this example) or of the second double-walled duct 230b (variant not illustrated). The circuit 20 further includes an air supply duct 25 fluidically connecting the third connection interface 103c of the blower and the inlet port 241 so as to allow a portion Fl of the airflow F of the blower to enter the peripheral channels 232a of the first 230a and second 230b double-walled ducts.

[0053] In this way, the invention proposes a simple solution to implement for ventilating, and therefore cooling, the central channel 231a of a double-walled duct 230a, 230b transporting fuel between the tank 520 located in the wing 52 of the aircraft 50 and the engine located in the turbojet 102. Air thus continuously supplies the peripheral channel 232a when the turbojet 102 is operating so that the central channel 231a of the double-walled ducts 230a and 230b is ventilated and cooled.

[0054] Although the second portion 23 of the circuit 20 passes through the second zone 111, which exhibits high temperatures, the invention allows for the safe transport of fuel between the tank 520 and the engine. This ventilation of the second portion 23 of the circuit 20 thus prevents any risk of clogging of the pipes due to the high temperatures of the second zone 111 through which the circuit 20 passes.

[0055] Indeed, the invention proposes pneumatic ventilation of the central channel 231a by drawing air from the blower so as to ventilate the peripheral channel 232a of the double-walled ducts 230a and 230b.

[0056] Thus, the peripheral channel 232a constitutes a zone to be ventilated with a volume significantly smaller than the volume of the second zone 111 which must be globally fully ventilated according to the solutions of the prior art.

[0057] This localized ventilation around the central channel 231a through which the fuel flows thus reduces the areas requiring ventilation within the compartment 106. In other words, it reduces the compartmentalization of the compartment 106, which necessitates sealing the different zones, notably through the manual application of sealant, and checking this sealing. Consequently, the invention results in significant time savings. This leads to considerable savings in manufacturing costs.

[0058] Finally, the invention provides a solution that improves the safety of fuel transport pipelines while reducing the risks of problems related to these pipelines in the presence of high temperatures.

[0059] As illustrated in [Fig. 5], the second connector 24 comprises a first plate 240a and a second plate 240b receiving respectively a first end 233a of the first double-walled conduit 230a and a first end 234a of the second double-walled conduit 230b. The second connector 24 also has a first sealing washer 242 arranged between the first 240a and second 240b plates.

[0060] As previously stated, the second connector 24 has an inlet port 241 which opens into the peripheral channel 232a of the first 230a or the second 230b double-walled conduit. More specifically, one of the plates 240a, 240b (the first plate 240a in this example) has the inlet port 241.

[0061] In order to allow fluid connection of the central channels 231a of the first 230a and second 230b double-walled conduits, the plates 240a and 240b and the first washer 242 each have a central bore 243a, 243b, 243c. The central bores thus ensure fluid continuity from the central channel 231a of the first double-walled conduit 230a to the central channel 231a of the double-walled conduit 230b.

[0062] Similarly, and to allow fluid connection of the peripheral channels 232a of the first 230a and second 230b double-walled conduits, the first plate 240a has a plurality of first holes 244a opening into the peripheral channel 232a of the first double-walled conduit 230a. The second plate 240b has, for each first hole 244a, a second hole 244b opening into the peripheral channel 232a of the second double-walled conduit 230b. Finally, the first washer 242 has, for each first hole 244a, a third hole 244c which fluidly connects the associated first hole 244a and second holes 244b.

[0063] Such a second connector 24 makes it possible to provide a simple solution for connecting an air supply from the blower to the double-walled ducts 230a and 230b so as to cool them continuously when the turbojet 102 is in operation.

[0064] Furthermore, such a second connector 24 makes it possible to provide a simple installation of the 20 piping circuit while adding ventilation to the double-walled ducts 230a and 230b. Such a second connector 24 also has a simple and therefore inexpensive structure.

[0065] More specifically, the central ducts 231 and peripheral ducts 232 of the first double-walled duct 230a are attached to the first plate 240a by welding. Similarly, the central ducts 231 and peripheral ducts 232 of the second double-walled duct 230b are attached to the second plate 240b by welding.

[0066] As illustrated in this example, the plates 240a and 240b each comprise a wall 246 whose cross-section is identical in shape to the cross-section of the peripheral conduit 232 and which extends coaxially to the double-walled conduits 230a and 230b. This wall 246 has a shoulder 247 to which the end of the peripheral conduit 232 of the associated double-walled conduit 230a or 230b is attached. Furthermore, near the central bore 243a, 243b of each plate 240a and 240b, a shoulder 248 is provided to which the end of the central conduit 231 of the associated double-walled conduit 230a or 230b is attached.

[0067] Preferably, the fixing is carried out by means of TIG welding (for "Tungsten Inert Gas" in English).

[0068] A welding fixing ensures optimal fixing of the central ducts 231 and peripheral ducts 232 to the plates 240a and 240b. Such a fixing also ensures optimal sealing of the junction between the double-walled ducts 230a and 230b and the plates 240a and 240b.

[0069] The second connector 24 further includes first clamping means 245 configured to clamp the first and second plates 240a, 240b towards each other. This allows the first and second plates to be brought closer together to compress / clamp the sealing washer 242. In this way, the risk of leakage within the second connector 24 is limited.

[0070] As illustrated in [Fig. 4], the first connector 22 comprises a third plate 220a receiving a first end 211 of the single-wall conduit 21 and a fourth plate 220b receiving a second end 233b of the first double-wall conduit 230a. The first connector 22 further comprises a second sealing washer 222 disposed between the third 220a and fourth 220b plates.

[0071] Furthermore, the fourth plate 220b here includes a discharge port 221 which opens into the peripheral channel 232a of the first double-walled conduit 230a and which fluidly connects the peripheral channel 232 of the first double-walled conduit 230a to the outside of the piping circuit 20. In this way, the flow portion Fl can circulate within the second portion 23 between the second connector 24 and the first connector 22. In addition, the discharge port 221 also allows the peripheral channel 232a to be drained in the event of a fuel leak from the central conduit 231a. The airflow portion Fl circulating in the peripheral channel 232a further assists in draining the fuel that has leaked from the central channel 231a to the peripheral channel 232a.

[0072] The single-wall conduit 21 delimits a central channel 212 into which the fuel flows.

[0073] Furthermore, the third and fourth plates 220a and 220b and the second washer 222 each have a central bore 223a, 223b, 223c. These central bores 223a, 223b, 223c fluidly connect the central channel 231 of said first double-walled conduit 230a and the central channel 212 of the single-walled conduit 21. The central bores 223a, 223b, 223c thus ensure fluid continuity of the channel central 212 of the single-walled duct 21 to the central channel 231a of the first double-walled duct 230a.

[0074] In particular, the single-wall conduit 21 is fixed to the third plate 220a by welding and the central conduit 231 and the peripheral conduit 232 of the first double-wall conduit 230a are fixed to the fourth plate 220b by welding.

[0075] As illustrated in this example, the third plate 220a has a wall 226 whose cross-section is identical in shape to the cross-section of the single-wall duct 21 and which extends coaxially to the single-wall duct 21. This wall 226 has a shoulder 227 to which the end 211 of the single-wall duct 21 is attached.

[0076] The fourth plate 220b also includes a wall 228 whose cross-section is identical to the cross-section of the peripheral conduit 232 of the first double-walled conduit 230a and which extends coaxially to the double-walled conduit 230a. This wall 228 has a shoulder 229a to which the end 233b of the peripheral conduit 232 of the first double-walled conduit 230a is attached. Furthermore, near the central bore 223b of the fourth plate 220b, a shoulder 229b is provided to which the end of the central conduit 231 of the first double-walled conduit 230a is attached.

[0077] Preferably, the single-wall duct 21 is attached to the third plate 220a by means of TIG welding (for "Tungsten Inert Gas"). The same applies to the attachment of the first double-wall duct 230a to the fourth plate 220b.

[0078] A welded fixing ensures optimal fixing of the single-wall duct 21 to the third plate 220a and of the central ducts 231 and peripheral ducts 232 of the first double-wall duct to the fourth plate 220b. Such a fixing also ensures optimal sealing of the junction between the single-wall duct 21 and the third plate 220a and between the first double-wall duct 230a and the fourth plate 220b.

[0079] As with the second connector 24, the first connector 22 has second clamping means 225 configured to clamp the third and fourth plates 220a, 220b towards each other. This allows the third and fourth plates 220a and 220b to be brought closer together to compress / clamp the second sealing washer 222. In this way, the risk of leakage within the first connector 22 is limited.

[0080] As illustrated in [Fig. 6], the second interface 26 comprises a fifth plate 261 receiving a second end 234b of the second double-walled conduit 230b. The fifth plate 26 comprises a central bore 263 which extends coaxially to the central conduit 231 of the second double-walled conduit 230b. The central bore 263 is, on the one hand, fluidically connected to the central conduit 231 of the second double-walled conduit 230b and is, on the other hand, intended to be fluidly connected to an engine fuel supply circuit, for example via a supply conduit (not shown).

[0081] The second interface 26 further includes a drain port 264 which fluidly connects the peripheral channel 232a of the second double-walled conduit 230b to the outside of the piping circuit 20. For example, the drain port 264 can be connected to piping connected to the aircraft's drain mast. This drain mast allows the pilot to check for leaks and determine the location of these leaks before takeoff.

[0082] In this way, the airflow portion Fl can circulate within the second portion 23 between the second connector 24 and the second interface 26. This drain orifice 264 allows the peripheral channel 232a to be emptied, i.e., drained, in the event of a fuel leak from the central conduit 231a. The airflow portion Fl circulating in the peripheral channel 232a also assists in draining the fuel that has leaked from the central channel 231a to the peripheral channel 232a.

[0083] The second portion 23 thus provides continuous ventilation of the central duct 231 carrying the fuel by directing a portion Fl of the airflow F from the blower into the peripheral channel 232a. This second portion 23 also ensures optimal drainage of the peripheral channel 232a thanks to the airflow Fl circulating within it.

[0084] As described previously, the reactor mast 104 includes a secondary structure 108 fixed below the casing 106 and at the rear of the fan. The second interface 26 includes third fastening means 265 which are configured to fix the second interface 26 to the secondary structure 108.

[0085] The first 245, second 225 and third 265 fastening means are conventional and are therefore not described in detail here. For example, the fastening means take the form of screws that allow the elements to be tightened together.

[0086] As illustrated in [Fig. 3], the single-wall conduit 21 of the circuit 20 extends above the housing 106, and more precisely above the upper stringer 106b. The first double-wall conduit 230a and / or the second double-wall conduit 230b pass through the housing 106 at at least one opening 112. In this example, the first double-wall conduit 230a passes through the upper stringer 106b and the lower stringer 106a at two openings 112. It is clear that, depending on the position of the second connector 24, it is possible that the second double-wall conduit 230b is the only one to pass through the housing 106, or that both the first 230a and the second 230b double-wall conduits pass through the housing 106.

[0087] Figure 7 illustrates a junction between an opening 112 provided in the box 106 and the circuit 20. Each opening 112 has a sealing gasket 27 configured to ensure sealing between the box 106 and the first double-walled duct 230a or the second double-walled duct 230b passing through the opening 112. The illustrated example shows the passage of the first double-walled duct 230a at the level of the lower stringer 106b, but it is understood that the junction would be identical for the passage of the second double-walled duct 230b through the lower stringer 106a or the lower stringer 106b.

[0088] The sealing gasket 27 includes a support 271 having a shape generally identical to the opening 112 (i.e., circular in this case). The support 271 includes a first surface 271a which extends parallel to the lower spar 106a and is fixed to it. The support 271 includes a second surface 271b which extends generally parallel to the first double-walled duct 230a and at a distance from it.

[0089] The sealing joint 27 further comprises a sealing element 272 having a first surface 272a enclosing the second surface 271b of the support 271 and a second surface 272b extending generally parallel to the lower longitudinal member 106b. The second surface 272b extends from the first surface 272a towards the first double-walled conduit 230a. A lip 272c extending from the second surface 272b encloses the first double-walled conduit 230a to ensure the seal of the joint.

[0090] Furthermore, [Fig. 7] illustrates a variant of a second connector 24 in which the inlet port 241 has been removed. Such a connector 24' allows, for example, two sections of the same double-walled duct to be connected (the first double-walled duct 230a in this example). Indeed, depending on the length or shape (for example, if bends are required), the first and second double-walled ducts can be divided into a plurality of sections extending in series. This connector 24' then ensures the continuity of the central channels 231a and peripheral channels 232a of two consecutive sections of a double-walled duct.

Claims

1. Demands Aircraft propulsion system (100) (50) comprising: - a tank (520) intended to contain fuel and to be disposed in a wing (52) of said aircraft (50), said tank (520) having a first connection interface (521); - a turbojet engine (102) comprising: • an engine having a second connection interface (26); and • a blower intended to blow an airflow (F) from the front to the rear of the aircraft (50), a third connection interface (103c) being disposed in the airflow downstream of the blower; - a piping circuit (20) comprising a first connector (22) and a single-wall conduit (21) extending between said first connection interface (521) of said tank (520) and said first connector (22), and a second portion (23) of piping comprising: • a second connector (24) disposed between said first connector (22) and said second interface (26) of said motor; • a first double-walled conduit (230a) extending between said first connector (22) and said second connector (24); • a second double-walled conduit (230b) extending between said second connector (24) and said second interface (26) of said motor, where said first (230a) and second (230b) double-walled conduits each comprise a central conduit (231) delimiting a central channel (231a) in which said fuel flows and a peripheral conduit (232) extending around said central conduit (231) and delimiting with said central conduit (231) a peripheral channel (232a); where said second connector (24) ensures fluidic continuity between the central channels (231a) of the first (230a) and second (230b)

2. double-walled conduits and fluidic continuity between the peripheral channels (232a) of the first (230a) and second (230b) double-walled conduits; where said second connector (24) has an inlet port (241) opening into said peripheral channel (232a) of the first double-walled duct (230a) or of the second double-walled duct (230b); said piping circuit (20) further comprising an air supply duct (25) fluidly connecting said third connection interface (103c) of the blower and said inlet port (241) so as to bring a portion (Fl) of said airflow (F) of the blower into said peripheral channels (232a) of the first (230a) and second (230b) double-walled ducts. System (100) according to claim 1, characterized in that said second connector (24) comprises: - a first plate (240a) and a second plate (240b) receiving respectively a first end (233a) of said first double-walled conduit (230a) and a first end (234a) of said second double-walled conduit (230b); - a first sealing washer (242) disposed between said first (240a) and second (240b) plates; where one of said plates (240a, 240b) has said inlet orifice (241); where said plates (240a, 240b) and said first washer (242) each have a central bore (243a, 243b, 243c), said central bores (243a, 243b, 243c) allowing to connect fluidly said central channels (231a) of said first (230a) and second (230b) double-walled conduits; and where said first plate (240a) has a plurality of first holes (244a) opening into the peripheral channel (232a) of said first double-walled conduit (230a), where said second plate (240b) has, for each first hole (244a), a second hole (244b) opening into the peripheral channel (232a) of said second double-walled conduit (230b), where said first washer (242) has, for each first hole (244a), a third hole (244c) fluidly connecting the associated first hole (244a) and second hole (244b).

3. System (100) according to claim 2, characterized in that said second connector (24) comprises first clamping means (245) configured to clamp said first and second plates (240a, 240b) towards each other.

4. System (100) according to any one of claims 1 to 3, characterized in that said first connector (22) comprises: - a third plate (220a) receiving a first end (211) of said single-wall conduit (21) and a fourth plate (220b) receiving a second end (233b) of said first double-wall conduit (230a); - a second sealing washer (222) disposed between said third (220a) and fourth (220b) plates; wherein said fourth plate (220b) comprises a discharge orifice (221) opening into said peripheral channel (232a) of said first double-wall conduit (230a) and fluidly connecting said peripheral channel (232) of said first double-wall conduit (230a) to the outside of said piping circuit (20);and where said third and fourth plates (220a, 220b) and said second washer (222) each have a central bore (223a, 223b, 223c), said central bores (223a, 223b, 223c) fluidly connecting said central channel (231) of said first double-walled conduit (230a) and said single-walled conduit (21).

5. System (100) according to claim 4, characterized in that said first connector (22) comprises second clamping means (225) configured to clamp said third and fourth plates (220a, 220b) towards each other.

6. System (100) according to any one of claims 1 to 5, characterized in that said second interface (26) comprises a fifth plate (261) receiving a second end (234b) of said second double-walled conduit (230b), said fifth plate (26) comprising: - a central bore (263) extending coaxially and being fluidly connected to said central conduit (231) of said second double-walled conduit (230b), said central bore (263) being further intended to be fluidly connected to a fuel supply circuit for said engine; - an evacuation orifice (264) fluidly connecting said peripheral channel (232a) of said second double-walled conduit (230b) to the outside of said piping circuit (20).

7. Aircraft (50) comprising a propulsion system (100) according to any one of claims 1 to 6 and a box (106) of a reactor pylon (104), said box (106) forming a primary structure and comprising a lower spar (106a), said propulsion system (100) being fixed to said lower spar (106a).

8. Aircraft (50) according to claim 7, characterized in that said single skin duct (21) extends above said box (106) and in that said first double skin duct (230a) and / or said second double skin duct (230b) pass through said box (106) at the level of at least one opening (112).

9. Aircraft (50) according to claim 8, characterized in that each opening (112) has a sealing gasket (27) configured to ensure sealing between said box (106) and said first double-skinned duct (230a) or said second double-skinned duct (230b) passing through said opening (112).

10. Aircraft (50) according to any one of claims 7 to 9, characterized in that it further comprises a secondary structure (108) fixed below said box (106) and behind said fan, said second interface (26) comprising third fastening means (265) configured to fix said second interface (26) to said secondary structure (108).

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