Exhaust system for turbine engine comprising heat exchanger

Abstract

The invention relates to an exhaust system (18) for a turbine engine. The exhaust system includes a nozzle (20) that at least partially defines a gas exhaust path. The system comprises a heat exchanger (26) comprising at least one distributor (28), at least one manifold (30), and conduits (32) configured for flowing a heat transfer fluid in the conduits (32) between the distributor and the manifold, the heat exchanger (26) configured to exchange heat between the gas discharge path (24) and the conduits (32), and the heat exchanger (26) is positioned on the orifice (20), the ducts (32) being partially formed by a surface (34) of the orifice (20).

Description

Technical Field

[0001] The present invention relates to heat recovery at the exhaust of a turbine engine.

[0002] In particular, the invention relates to heat recovery for heating fuel and / or air intended to enter a combustion chamber of said turbine engine.

[0003] In general, the present invention is applicable to any type of exhaust system. Background Art

[0004] Figure 1 A turbine engine 2 of an aircraft according to the prior art is schematically shown. The turbine engine 2 comprises a fan 4 capable of recovering air from the atmosphere outside the turbine engine 2, a compressor 6, a combustion chamber 8, a turbine 10 and an exhaust system 12. In order to improve the performance of the turbine engine, the air and / or the fuel leaving the compressor 6 and / or the fuel entering the combustion chamber 8 with the air can be heated.

[0005] A heat source located nearby is preferred to improve the thermal efficiency of the turbine engine 2. The heat source is constituted, for example, by the gases exiting through the exhaust system 12 downstream of the turbine 10. However, positioning the heat exchanger in the main exhaust flow 14 (for example in the form of fins positioned in the flow) causes a pressure drop in the turbine engine 2, which has an adverse effect on the thrust of the aircraft. Positioning the heat exchanger in the turbine engine 2 also adversely affects the compactness of said turbine engine 2. Summary of the invention

[0006] The object of the present invention is therefore to overcome the above-mentioned drawbacks and to provide an exhaust system which makes it possible to effectively recover heat at the exhaust of a turbine engine. To this end, the present invention is the result of technical research aimed at very significantly improving the performance of aircraft and, in this sense, contributes to reducing the impact of aircraft on the environment.

[0007] The object of the present invention is an exhaust system for a turbine engine, the exhaust system comprising a nozzle at least partially defining a gas exhaust path, the exhaust system further comprising a heat exchanger, the heat exchanger comprising at least one distributor, at least one manifold and pipes, the pipes being configured for allowing a heat transfer fluid in the pipes to flow between the distributor and the manifold, the heat exchanger being configured for heat exchange between the gas exhaust path and the pipes, and the heat exchanger being positioned on the nozzle, the pipes being partially formed by the surface of the nozzle.

[0008] The exhaust system according to the invention thus makes it possible to recover heat from the exhaust of a turbine engine at the periphery of the exhaust path without causing a significant pressure drop in the turbine engine, the heat exchanger being particularly compact and non-intrusive.

[0009] Preferably, the nozzle comprises an annular outer portion and a central body, the heat exchanger being positioned on the outer portion and / or on the central body.

[0010] Advantageously, the outer portion of the nozzle comprises one or more annular segments.

[0011] In various embodiments, the conduits are positioned outside or inside the gas exhaust path.

[0012] In one embodiment, the ducts have a semicircular, or rectangular, or bell-shaped, or semi-elliptical, or triangular cross-section.

[0013] Advantageously, the ducts extend longitudinally parallel to the longitudinal axis of the exhaust system, or transversely to the longitudinal axis.

[0014] In one embodiment, the exhaust system is made of a material comprising a titanium alloy and / or a nickel alloy.

[0015] Advantageously, the heat exchanger is configured to exchange heat between exhaust gases exiting through the gas exhaust path and a heat transfer fluid flowing in these pipes, the heat transfer fluid comprising air, and / or water vapor, and / or water, and / or fuel, and / or oil, and / or supercritical carbon dioxide (CO2), and / or liquid or gaseous hydrogen.

[0016] Another object of the present invention is a turbine engine comprising a compressor, a combustion chamber and an exhaust system as described above, the heat exchanger being configured to heat the fuel at the inlet of the combustion chamber and / or to heat the air at the outlet of the compressor before the fuel and / or air enters the combustion chamber.

[0017] Another object of the invention is an aircraft comprising a turbine engine as described above and / or an exhaust system as described above.

[0018] The invention further relates to the use of an exhaust system as described above in a thermal management system for heating air or fuel in a turbine engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other objects, features and advantages of the present invention will become apparent on reading the following description given by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0020] [ Figure 1 ] is a schematic longitudinal cross-sectional view of a turbine engine of an aircraft according to the prior art;

[0021] [ Figure 2 ] is a schematic longitudinal section of a turbine engine of an aircraft according to the invention;

[0022] [ Figure 3 ] is a schematic diagram of a first embodiment of an exhaust system for a turbine engine according to the present invention;

[0023] [ Figure 4 ]yes Figure 3 A schematic diagram of a first variant of a first embodiment of an exhaust system for a turbine engine is shown;

[0024] [ Figure 5 ]yes Figure 3 A schematic diagram of a second variation of the first embodiment of an exhaust system for a turbine engine is shown;

[0025] [ Figure 6 ]yes Figure 3 A schematic diagram of a third variation of the first embodiment of an exhaust system for a turbine engine is shown;

[0026] [ Figure 7 ] is a schematic diagram of a second embodiment of an exhaust system for a turbine engine according to the present invention;

[0027] [ Figure 8 ] includes the outer layer Figure 3 A schematic diagram of a first embodiment of an exhaust system;

[0028] [ Fig. 9 ] is a schematic cross-sectional view of a pipe having a semicircular cross section; and

[0029] [ Fig.10 ] is a schematic cross-sectional diagram of a pipe with a triangular cross section. DETAILED DESCRIPTION

[0030] Figure 2 A turbine engine 16 of an aircraft according to the invention is schematically shown. The turbine engine 16 comprises a fan 4 capable of recovering air from the atmosphere outside the turbine engine 16, a compressor 6, a combustion chamber 8, a turbine 10 and an exhaust system 18.

[0031] In particular, the exhaust system 12 includes a nozzle 20, which preferably includes an annular outer portion 21 and a center body 22, thereby forming an annular cross-section gas exhaust path 24. The exhaust system 18 also includes a heat exchanger 26, which is configured to heat the fuel at the inlet of the combustion chamber 8 and / or heat the air at the outlet of the compressor 6 before the fuel and / or air enters the combustion chamber 8.

[0032] Figure 3 A first embodiment of the exhaust system 18 is schematically shown, wherein a heat exchanger 26 is positioned on the outer portion 21 of the nozzle 20, Figure 3As a variant, the heat exchanger 26 can be positioned on the central body 22 of the exhaust system 18 by analogy.

[0033] The heat exchanger 26 includes at least one distributor 28 , at least one manifold 30 , and conduits 32 .

[0034] The distributor 28 is configured to inject the heat-transfer fluid into pipes 32 , which are themselves configured to flow said heat-transfer fluid in said pipes 32 , up to a manifold 30 , which is configured to recover the heated heat-transfer fluid.

[0035] The heat transfer fluid includes, for example, air, and / or water vapor, and / or water, and / or fuel, and / or oil, and / or supercritical CO2 and / or liquid hydrogen, and / or fuel supplied to the turbine engine 16. For example, liquid hydrogen can be used as a fuel and is advantageously used as a heat transfer fluid because liquid hydrogen is a cold fuel and has a boiling temperature of approximately 20 Kelvin.

[0036] The duct 32 is formed partly by a surface 34 of the outer portion 21 of the nozzle 20 or partly by a surface of the central body, if applicable. This surface is the surface of the nozzle wall (also called main exhaust wall) against which the exhaust gas is discharged.

[0037] The duct 32, as well as the distributor 28 and the manifold 30, are preferentially positioned on the outer surface 34 of the wall of the outer portion 21 of the nozzle 20, in other words outside the discharge path 24, so as not to interfere with the discharge flow. As a variant, the duct 32 can still be positioned on the inner surface of the wall of the nozzle 20, in other words inside the discharge path 24. Advantageously, the duct 32 is distributed over the entire periphery of the discharge path 24.

[0038] Thus, the heat exchanger 26 is configured to exchange heat between the gas exhaust path 24 and the conduit 32 via one or more walls of the nozzle 20 .

[0039] like Figure 3 The exhaust system 18 shown includes four annular segments 36 of substantially equal size, at least one manifold 30, at least one distributor 28, and a conduit 32 positioned on each segment 36, the manifolds 30 and distributors 28 adjacent two different segments 36 being connected by a pipe 38. In variants, the exhaust system 18 includes a single annular segment or a plurality of annular segments.

[0040] exist Figure 3 In the illustrated embodiment, the conduit 32 extends along the periphery of the outer portion 21 of the nozzle 20 , transverse to the longitudinal axis L of the exhaust system 18 .

[0041] Furthermore, the heat exchanger 26 comprises a non-curved conduit 32 , the only curvature of which is the curvature of the outer portion 21 of the nozzle 20 .

[0042] Figure 4 A first variant of the first embodiment is schematically shown.

[0043] In this first variant, the duct 32 extends meanderingly along the periphery of the outer portion 21 of the nozzle 20. In particular, the duct 32 has an elbow 40 with an angle substantially equal to 180°, so that each manifold 30 and distributor 28 comprises a small number of inlets and outlets to the duct 32, thereby minimizing the flow rate of the fluid flowing through the heat exchanger.

[0044] Figure 5 A second variant of the first embodiment is schematically shown. Figure 3 The embodiment of FIG. 1 is identical except that the conduit 32 extends longitudinally and substantially parallel to the longitudinal axis L of the exhaust system 18 .

[0045] Figure 6 A third variant of the first embodiment is schematically shown. Figure 4 The embodiment of is identical, except that the duct 32 extends longitudinally and substantially parallel to the longitudinal axis L of the exhaust system 18. The duct 32 also has a bend 40 with an angle substantially equal to 180°.

[0046] Figure 7 A second embodiment of the exhaust system 18 is schematically shown, wherein a heat exchanger 26 is positioned on the outer portion 21 of the nozzle 20 .

[0047] In this embodiment, the conduit 32 is positioned inside the exhaust path 24, while the distributor 28 and the manifold 30 are positioned outside the exhaust path 24. The conduit 32 extends substantially parallel to the longitudinal axis L of the exhaust system 18.

[0048] This embodiment makes it possible to increase the heat exchanger surface, to the detriment of the slight pressure drop in the main flow of the turbine engine.

[0049] In each embodiment, the exhaust system 18 is made of a heat-resistant material, such as a material including a titanium alloy and / or a nickel alloy.

[0050] In each embodiment, the exhaust system 18 may optionally include: Figure 8 An outer skin 42 is shown, which is arranged annularly around the heat exchanger 18 and serves as an aerodynamic fairing for the flow of the secondary path or for any other flow from the turbine engine. The exhaust system may also include flanges 44 at the longitudinal ends of the nozzle 20 in order to attach said nozzle 20 to the turbine engine 2.

[0051] In various embodiments, the duct 32 has a cross section that is, for example, semicircular, or rectangular, or bell-shaped, or semi-elliptical, or also triangular. The shape of the cross section of the duct 32 further makes it possible to easily remove the duct from the mold during its manufacture.

[0052] Fig. 9 A cross-sectional view of a duct 32 having a semicircular cross section is schematically shown. The cross-sectional view here is taken along the longitudinal axis of the exhaust system 18. The duct 32 shown is, for example, Figure 3 The pipes 32 shown in the embodiment of .They are protected by an outer layer 42.

[0053] Fig.10 1 shows a cross-sectional view of a pipe 32 having a triangular cross-section. The cross-sectional view is taken transversely to the longitudinal axis L of the exhaust system 18. The pipe 32 shown is, for example, Figure 7 The pipes 32 shown in the embodiment of the present invention are positioned in the discharge path 24 and extend parallel to the longitudinal axis L of the discharge system. The triangular cross section of the pipes 32 enables a large heat exchange surface and a low pressure drop. In addition, one of the sides of each pipe 32 is advantageously oriented radially in the direction of the longitudinal axis L, so that each pipe is easily removed from the mold during the manufacture of the discharge system 18.

[0054] Furthermore, for each embodiment, it is preferably manufactured by diffusion welding a stack of a plurality of sheets, with inert gas injected at desired locations of the pipe 32. Diffusion welding makes it possible to avoid the reduction of weld seams, thereby making it possible to produce an exhaust system 18 having substantially the same characteristics as if the exhaust system were produced integrally.

Claims

1. An exhaust system (18) for a turbine engine (16), the exhaust system comprising a nozzle (20) at least partially defining a gas exhaust path (24), characterized in that: The exhaust system comprises a heat exchanger (26), the heat exchanger comprising at least one distributor (28), at least one manifold (30) and a pipe (32), the pipe being configured to allow a heat transfer fluid in the pipe (32) to flow between the distributor (28) and the manifold (30), the heat exchanger (26) being configured to perform heat exchange between the gas exhaust path (24) and the pipe (32), and the heat exchanger (26) being positioned on the nozzle (20), the pipe (32) being partially formed by a surface (34) of the nozzle (20).

2. The exhaust system according to claim 1, wherein: The nozzle (20) comprises an annular outer portion (21) and a central body (22), the heat exchanger (26) being positioned on the outer portion (21) and / or on the central body (22).

3. The exhaust system according to claim 2, wherein: The outer portion (21) of the nozzle (20) comprises one or more annular segments (36).

4. The exhaust system according to any one of claims 1 to 3, wherein: The duct (32) is positioned outside or inside the gas exhaust path (24).

5. The exhaust system according to any one of claims 1 to 4, wherein: The duct (32) extends longitudinally parallel to a longitudinal axis (L) of the exhaust system, or transversely to the longitudinal axis (L).

6. The exhaust system according to any one of claims 1 to 5, wherein the exhaust system is made of a material comprising a titanium alloy and / or a nickel alloy.

7. The exhaust system according to any one of claims 1 to 6, wherein: The heat exchanger (26) is configured to exchange heat between the exhaust gas exiting through the gas exhaust path (24) and a heat transfer fluid flowing in the pipe (32), the heat transfer fluid comprising air, and / or water vapor, and / or water, and / or fuel, and / or oil, and / or supercritical CO2, and / or liquid or gaseous hydrogen.

8. A turbine engine (16), comprising a compressor (6) and a combustion chamber (8), characterized in that: The turbine engine comprises an exhaust system (18) according to any one of claims 1 to 7, the heat exchanger being configured to heat the fuel at the inlet of the combustion chamber (8) and / or to heat the air at the outlet of the compressor (6) before the fuel and / or the air enter the combustion chamber (8).

9. An aircraft, characterized in that: The aircraft comprises a turbine engine (16) according to claim 8 or an exhaust system (18) according to any one of claims 1 to 7.

10. Use of an exhaust system (18) according to any one of claims 1 to 7 in a thermal management system for heating air or fuel in a turbine engine (16).

Images