Propulsion assembly for aircraft and aircraft

Abstract

The invention relates to a propulsion assembly (151) for an aircraft and an aircraft, the propulsion assembly having a combustion chamber (168) and a fairing (172), an exhaust nozzle (174) delimited by a nozzle wall (180), a dihydrogen tank (178), and a supply conduit (176) between the tank (178) and the combustion chamber (168), the supply conduit has a first portion (176a) between the canister (178) and the nozzle wall (180), a second portion (176b) between the nozzle wall (180) and the combustion chamber (168), and an intermediate portion (176c) housed in the exhaust nozzle (174), and wherein each portion has a first end (182a) connected to the first portion (176a) by the nozzle wall (180) and a second end (182b) connected to the second portion (176b) by the nozzle wall (180). With such an arrangement, the thermal energy of the combustion gas is transferred to the dihydrogen for better combustion.

Description

Technical Field

[0001] The invention relates to a propulsion assembly for an aircraft and to an aircraft having at least one such propulsion system, the propulsion assembly comprising a propulsion system having an exhaust nozzle, which ensures the discharge of combustion gases from the propulsion system, and a heat exchange system arranged in the exhaust nozzle for ensuring the transfer of thermal energy to dihydrogen supplying the propulsion system. Background Art

[0002] For movement, an aircraft generally has at least one propulsion assembly comprising a propulsion system arranged in the cabin and which may take the form of a jet engine or a turboprop. In each case, the propulsion system has a rotating assembly driving a fan or a propeller. The rotating assembly constitutes the core of the propulsion system and has, from front to back: an air inlet allowing air to be introduced into the ducts of the core; a compressor which compresses the air thus introduced, a combustion chamber in which the thus compressed air and fuel are mixed; and a turbine which allows the combustion gases to expand and which generates a rotation transmitted to the fan or the propeller.

[0003] Downstream of the turbine, exhaust nozzles ensure the discharge of the combustion gases.

[0004] It is also known that, particularly in the case of dihydrogen, the combustion efficiency of the fuel is improved if the fuel is heated prior to said combustion.It is also known to use some of the hot combustion gases discharged by the exhaust nozzle to heat the fuel. Summary of the invention

[0005] The object of the present invention is to propose another solution for heating dihydrogen before its combustion in a completely safe manner.

[0006] To this end, a propulsion assembly for an aircraft is proposed, the propulsion assembly having:

[0007] - a propulsion system comprising a cowl, a rotating assembly having a combustion chamber and housed in the cowl, an exhaust nozzle arranged downstream of the combustion chamber and delimited by a rear portion of the cowl, called the nozzle wall, and which ensures the exhaust of combustion gases originating from the combustion of dihydrogen in the combustion chamber,

[0008] - Dihydrogen tank, and

[0009] - a supply duct connecting the canister to the combustion chamber and having: a first portion extending between the canister and the nozzle wall; a second portion extending between the nozzle wall and the combustion chamber; and a plurality of intermediate portions housed inside the exhaust nozzle and wherein each portion has a first end portion connected to the first portion by the nozzle wall fluid; and a second end portion connected to the second portion by the nozzle wall fluid.

[0010] With such an arrangement, the thermal energy of the combustion gases is transferred to the dihydrogen by passing through the middle portion of the nozzle.

[0011] Advantageously, each intermediate portion extends over an angular sector around the longitudinal axis of the exhaust nozzle.

[0012] Advantageously, a plurality of intermediate portions are provided which are continuous along the longitudinal axis of the exhaust nozzle.

[0013] Advantageously, the consecutively arranged intermediate portions are spaced apart from one another.

[0014] Advantageously, the supply conduit is a double-walled conduit having an inner wall delimiting an inner volume and an outer wall delimiting an outer volume in which the dihydrogen circulates.

[0015] Advantageously, the outer volume is evacuated.

[0016] Advantageously, the supply duct has a spacer fastened between the inner wall and the outer wall.

[0017] Advantageously, the outer surface of the supply duct is provided with fins.

[0018] The invention also proposes an aircraft having at least one propulsion assembly according to one of the previous variants. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above-mentioned features and other features of the present invention will become more apparent upon reading the following description of an exemplary embodiment, which is given with reference to the accompanying drawings, in which:

[0020] Figure 1 is a side view of an aircraft having a propulsion assembly according to the present invention,

[0021] Figure 2 is a side view and a schematic cross-sectional view of a propulsion assembly according to the present invention,

[0022] Figure 3 It is along Figure 2 A cross-sectional view taken along line III-III in FIG.

[0023] Figure 4is a perspective view of one specific embodiment of a supply conduit implemented in the present invention. DETAILED DESCRIPTION

[0024] In the following description, the terms related to position are considered to be related to the aircraft in a forward motion position, i.e. Figure 1 As shown in Figure 1 The middle arrow F shows the forward movement direction of the aircraft.

[0025] Figure 1 An aircraft 100 is shown having a fuselage 102, on either side of which wings 104 are fastened. Under each wing 104 at least one propulsion assembly 151 is fastened.

[0026] Figure 2 A propulsion assembly 151 is shown, which includes a nacelle 149 and a propulsion system 150 surrounded by the nacelle 149. In the embodiment of the invention presented here, the propulsion system 150 takes the form of a turboprop engine having a propeller 152, which is driven to rotate by a rotating assembly inside a fairing 172 of the propulsion system 150 housed inside the nacelle 149, but the propulsion system 150 may also take the form of a jet engine driving a fan. Therefore, the propulsion system 150 generally has a rotating assembly and a movable element 152 (propeller or fan).

[0027] In the following description, and by convention, X denotes the longitudinal axis of the propulsion system 150, which corresponds to the axis of rotation of the movable element 152 having a positive orientation in the direction of forward movement of the aircraft 100, Y denotes the lateral axis of the propulsion system 150, which is horizontal when the aircraft is on the ground, and Z denotes the vertical axis of the propulsion system 150 or the vertical height of the aircraft when it is on the ground; these three axes X, Y and Z are orthogonal to each other.

[0028] Figure 2A propulsion system 150 is shown in the case of a turboprop. A rotating assembly 160 constitutes the core of the propulsion system 150 and has, from front to rear: an air inlet 162 allowing the introduction of air into a duct 164 of the core, a compressor 166 compressing the air thus introduced, a combustion chamber 168 in which the thus compressed air and dihydrogen are mixed and burned, and a turbine 170 allowing the combustion gases to expand and which generates a rotation transmitted to a movable element, which in this case is the propeller 152. The elements of the rotating assembly 160 are surrounded by a fairing 172 formed by structural shells mounted around the elements of the rotating assembly 160 and making it possible to stiffen the rotating assembly 160 in particular to limit its deformations during operation.

[0029] The cowling 172 opens forwards at the air inlet 162 on the one hand and delimits the duct 164, and opens forwards at the exhaust nozzle 174 on the other hand, which is located downstream of the turbine 170 and therefore downstream of the combustion chamber 168 and ensures the discharge of the combustion gases originating from the combustion of dihydrogen with air in the combustion chamber 168. The rear part of the cowling 172 surrounding the exhaust nozzle 174 forms a nozzle wall 180.

[0030] The space between the nacelle 149 and the fairing 172 is occupied by various systems ensuring the operation of the propulsion system 150. In particular, in order to supply the combustion chamber 168 with dihydrogen, the propulsion assembly 151 has a dihydrogen tank 178, which in this case is housed in the wing 104, a supply duct 176 connecting the tank 178 to the combustion chamber 168, and a pump 179 which moves the dihydrogen from the tank 178 through the supply duct 176 to the combustion chamber 168. The dihydrogen tank 178 can also be housed in another part of the aircraft 100, for example in the fuselage 102, without departing from the scope of the invention.

[0031] In order to heat the dihydrogen before injecting it into the combustion chamber 168 so as to achieve better combustion, the propulsion assembly 151 also has a heat exchanger system 200, which is arranged in the exhaust nozzle 174 and is arranged to ensure that heat energy is exchanged between the hot combustion gases circulating in the exhaust nozzle 174 and the cooler dihydrogen circulating in the supply duct 176 when the propulsion system 150 is in operation.

[0032] The supply conduit 176 has a first portion 176 a extending between the can 178 and the nozzle wall 180 , and a second portion 176 b extending between the nozzle wall 180 and the combustion chamber 168 .

[0033] In order to ensure that the dihydrogen circulating in the supply duct 176 is heated, the supply duct 176 also has a plurality of intermediate portions 176 c housed inside the exhaust nozzle 174 , ie inside the volume delimited by the nozzle wall 180 .

[0034] Figure 3 A cross section through the exhaust nozzle 174 is shown at a plurality of intermediate portions 176c. Each intermediate portion 176c has a first end 182a, which is fluidically connected to the first portion 176a via the nozzle wall 180, and a second end 182b, which is fluidically connected to the second portion 176b via the nozzle wall 180. Thus, the intermediate portion 176c is accommodated in the exhaust nozzle 174 and is thereby immersed in the combustion gases, and thus the dihydrogen circulating in the intermediate portion 176c is heated. The first portion 176a and the second portion 176b are arranged outside the exhaust nozzle 174.

[0035] Each first end 182a is thus entirely fluidly connected to the first portion 176a, and each second end 182b is thus entirely fluidly connected to the second portion 176b.

[0036] This division into a plurality of intermediate portions 176 c makes it possible to divide the supply duct 176 into a plurality of portions and thus distribute the dihydrogen into these intermediate portions 176 c, instead of having a single long portion inside the exhaust nozzle 174. Such an arrangement makes it possible to limit in particular the forces applied to each intermediate portion 176 c, compared to the forces that would be applied to the long portion.

[0037] The first end 182 a and the first portion 176 a are coupled, for example, by an upstream manifold 201 , and the second end 182 b and the second portion 176 b are coupled, for example, by a downstream manifold 202 .

[0038] In order to limit as much as possible the forces applied to the intermediate portions 176 c while maximizing the heat exchange surface area, the individual intermediate portions 176 c are distributed over the circumference of the exhaust nozzle 174 .

[0039] Exhaust nozzle 174 has a longitudinal axis X′, which may or may not be parallel to longitudinal axis X of propulsion system 150 depending on the arrangement of nozzle wall 180 .

[0040] Thus, each intermediate portion 176c extends over an angular sector about the longitudinal axis X' of the exhaust nozzle 174. According to a particular embodiment, each intermediate portion 176c extends over an angle between 40° and 50° and at least four intermediate portions 176c are provided distributed over the circumference.

[0041] In the same way, the dihydrogen can be distributed over the length of the exhaust nozzle 174. According to a particular embodiment, a plurality of intermediate portions 176c are provided, which are arranged in series along the longitudinal axis X' of the exhaust nozzle 174. Figure 2 In the embodiment, four middle parts 176c are continuously arranged.

[0042] In order to ensure that the heat transfer between the consecutively arranged intermediate parts 176c is as efficient as possible, the intermediate parts 176c are spaced apart from each other. Thus, there is a space between two consecutive intermediate parts 176c, thereby allowing the combustion gas to circulate between the intermediate parts 176c.

[0043] In addition, for safety reasons and if Figure 4 As shown in the figure, the supply conduit 176, i.e., the first part 176a, the second part 176b and each intermediate part 176c, is configured to be a double-walled conduit having an inner wall 402 defining an internal volume 404 in which dihydrogen circulates and an outer wall 406 surrounding the inner wall 402, and wherein an external volume 408 that does not contain dihydrogen under normal operating conditions, i.e., when there is no leakage, is defined between the inner wall 402 and the outer wall 406.

[0044] Thus, even if there is a leak at the inner wall 402, the dihydrogen will diffuse in the outer volume 408 while remaining isolated from the hot combustion gases.

[0045] The outer volume is preferably evacuated so if there is a leak at the outer wall 406, the outer volume 408 will fill with hot combustion gases while remaining isolated from the dihydrogen.

[0046] In order to prevent the leakage of dihydrogen at the middle part 176c, the heat exchanger system 200 may have a leakage detection device and a control unit connected to the leakage detection device. The heat exchanger system 200 also has a valve installed on the first part 176a and opened and closed by the control unit. When the leakage detection device detects the leakage of dihydrogen at the inner wall 402 or the outer wall 406 of the middle part 176c, the control unit closes the valve.

[0047] The leakage detection device is, for example, a pressure sensor arranged in the external volume 408, and since the pressure in the external volume 408 is different from the pressure of the dihydrogen in the internal volume 404 and the pressure of the atmosphere outside the middle part 176c, leakage from the inner wall 402 or from the outer wall 406 will be detected by the pressure sensor due to the pressure change in the external volume 408.

[0048] When the external volume is evacuated, the external volume is, for example, fluidly connected to a vacuum pump 220 .

[0049] To ensure that the outer wall 406 is correctly held around the inner wall 402, the supply duct 176 has spacers 410 secured between the inner wall 402 and the outer wall 406 and thus in the outer volume 408. In the embodiment of the invention presented here, each spacer 410 extends radially around the inner wall 402.

[0050] In order to improve the heat exchange between the hot combustion gases and the dihydrogen, the outer surface of the supply conduit 176, whether single-walled or double-walled, is equipped with fins 412 made of a material with high thermal conductivity and integral with the outer surface. The fins 412 are thus immersed in the hot combustion gases.

Claims

1. A propulsion assembly (151) for an aircraft (100), comprising: a propulsion system (150) comprising a cowling (172), a rotating assembly (160) having a combustion chamber (168) and housed in said cowling (172), an exhaust nozzle (174) arranged downstream of said combustion chamber (168) and delimited by a rear portion of said cowling (172) called a nozzle wall (180), and said propulsion system (150) ensuring the exhaust of combustion gases originating from the combustion of dihydrogen in said combustion chamber (168), - a dihydrogen tank (178), and a supply conduit (176) connecting the tank (178) to the combustion chamber (168), the supply conduit (176) having a first portion (176a) extending between the tank (178) and the nozzle wall (180), a second portion (176b) extending between the nozzle wall (180) and the combustion chamber (168), and a plurality of intermediate portions (176c) received inside the exhaust nozzle (174), and wherein, Each portion has a first end (182a) fluidly connected to the first portion (176a) through the nozzle wall (180); and a second end (182b) fluidly connected to the second portion (176b) through the nozzle wall (180).

2. The propulsion assembly (151) according to claim 1, wherein: Each intermediate portion (176c) extends over an angular sector about the longitudinal axis (X') of the exhaust nozzle (174).

3. The propulsion assembly (151) according to claim 2, wherein: A plurality of intermediate portions (176c) are continuously arranged along the longitudinal axis (X') of the exhaust nozzle (174).

4. The propulsion assembly (151) according to claim 3, wherein: The middle portions (176c) arranged in series are spaced apart from each other.

5. The propulsion assembly (151) according to claim 1, wherein: The supply conduit (176) is a double-walled conduit having an inner wall (402) defining an inner volume (404) in which the dihydrogen circulates and an outer wall (406) defining an outer volume (408).

6. The propulsion assembly (151) according to claim 5, wherein: The outer volume (408) is evacuated.

7. The propulsion assembly (151) according to claim 5, wherein: The supply conduit (176) has a spacer (410) secured between the inner wall (402) and the outer wall (406).

8. The propulsion assembly (151) according to claim 1, wherein: The outer surface of the supply duct (176) is provided with fins (412).

9. An aircraft (100) having at least one propulsion assembly (151) according to claim 1.

Images