Structural beam turbomachine including a discharge duct

Abstract

The present invention relates to a turbomachine (110) comprising: a main channel (171), an auxiliary channel (173) separated from the main channel (171) by a central compartment (12), a discharge duct (2) extending in the central compartment (12) from a sampling port (21) to an air outlet (22) opening into the auxiliary channel (12), the discharge duct (2) comprising a first portion (221) formed in the central compartment (12) and a second portion (222) formed in a structural beam (4) of the central compartment (12), the structural beam (4) extending along the auxiliary channel (173) and being adapted to impart rigidity to the central compartment (12), the discharge duct (2) being adapted to draw air from the main channel (171) and direct it to an auxiliary channel (173). Figure for the abstract: Fig. 2

Description

Title of the invention: Structural beam turbomachine comprising a discharge duct technical field

[0001] The present description relates to the general field of propulsion systems, in particular to turbomachines with an unfaired propeller, with at least two flow paths, intended for aircraft propulsion. Turbomachines with at least two flow paths refer more specifically to turbomachines known as "double-flow turbomachines" or "triple-flow turbomachines".

[0002] The present description relates more particularly to a turbomachine comprising a relief duct for reducing the pressure downstream of the low-pressure compressor of an aircraft turbomachine with at least two flow paths, and to an aircraft turbomachine with at least two flow paths equipped with such a relief duct. PRIOR TECHNOLOGY

[0003] A turbomachine has a longitudinal axis around which it extends and typically comprises, from upstream to downstream in the direction of gas flow, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, and a low-pressure turbine including, in particular, an exhaust casing. The air entering the turbomachine is compressed by the fan and then splits into a primary airflow, which passes through the primary casing, and a secondary airflow that bypasses the primary airflow, and optionally a tertiary airflow that bypasses the primary flow.

[0004] Furthermore, such a turbomachine generally includes a discharge conduit which makes it possible to avoid the phenomenon of pumping or stalling of the low pressure compressor.

[0005] In a compressor in general, and more specifically in a low-pressure compressor, the air is compressed so that it exits the compressor at a higher pressure than the inlet pressure. However, similarly to an aircraft wing that can lose lift and "stall" when it is at a high angle of attack and the aircraft is at low speed, a compressor can undergo a similar phenomenon.

[0006] Thus, at reduced flow rate, the compressor no longer pushes the airflow downstream, and the high-pressure air downstream of the compressor empties towards the compressor inlet, which is at a lower pressure. A reversal of the airflow direction may even occur. Once sufficient air discharge has occurred, the compressor can return to normal operating conditions and restore the airflow in the correct direction (from upstream to downstream). Such cyclical fluctuations in flow are called "pumping".

[0007] Such a phenomenon can however be destructive to the compressor blades and cause their destruction or at the very least cause vibrations in them.

[0008] In order to avoid these problems, it is known to install at least one discharge conduit, downstream of the low pressure compressor and upstream of the high pressure compressor.

[0009] This discharge duct is configured to be connected to a discharge valve, or sampling port, known by the English acronym VBV (for "Variable Bleed Valve") or by the French acronym VDV (for "Vanne de déboudre variable"). This discharge valve, which forms the radially internal end of the discharge duct, is positioned in the primary airflow.

[0010] The turbomachine also comprises various casings, including an intermediate casing (interposed between the low-pressure compressor and the high-pressure compressor of the turbomachine, and therefore traversed by a gas flow exiting the low-pressure compressor and intended to supply the high-pressure compressor) and a casing associated with the intermediate casing, called the "engine kit," namely a casing mechanically structured by service passage arms that connect the first intermediate wall to an outer shell of the engine kit. This outer shell forms part of the wall that externally delimits a secondary gas stream. A heat exchanger is also located at this point to dissipate heat in the cooler secondary flow. The "engine kit" casing is positioned directly downstream of the aforementioned intermediate casing, adjacent to it, along the engine axis.Currently, it is known to place the radially external end of the discharge duct, i.e., an outlet for the extracted air, within this engine kit.

[0011] However, in order to increase the overall rigidity of the turbomachine and this casing arrangement, the engine kit is replaced by a new structural casing. This poses a problem for the design of the discharge duct, as mechanical constraints prevent the air outlets from being located within the structural casing. Furthermore, numerous components and utilities located directly upstream and downstream impose integration constraints, making it difficult to position the outlets near their original location. Moreover, a discharge duct with a complex geometry can result in a significant pressure drop due to the changes in direction imposed on the air within this modified duct. Finally, a large discharge duct outlet angle causes aerodynamic disturbance, particularly behind the heat exchanger.The same problems are encountered with a triple-flow turbomachine, which is also threatened by the pumping phenomenon.

[0012] There is therefore a need for a new discharge duct with a simple geometry and an air outlet placement that meets the various constraints. Description of the invention

[0013] One object of the invention is to remedy the aforementioned drawbacks by proposing a turbomachine comprising: - a main channel configured to supply at least one compression stage with air, - an auxiliary channel separated from the main channel by a central compartment, the main channel and the auxiliary channel extending around an axis that runs from upstream to downstream in the direction of airflow in the turbomachine, - a discharge duct extending into the central compartment of a sampling vent, opening into the main channel, to an air outlet opening into the auxiliary channel, the sampling vent being configured to draw air from the main channel, the discharge duct comprising a first portion formed in the central compartment and a second portion formed in a structural beam of the central compartment,

[0014] the structural beam extending along the auxiliary channel and being adapted to impart rigidity to the central compartment, the discharge duct being adapted to draw air from the main channel and bring it to an auxiliary channel.

[0015] The turbomachine according to the invention is advantageously complemented by the following features, taken alone or in any technically possible combination thereof: - an arm extending radially from the central compartment through the auxiliary channel, the structural beam being positioned opposite the arm, the first portion of the discharge conduit then passing through the arm; - the structural beam is attached to the arm by means of bolts; - a sealing gasket placed at an interface between the arm and the beam structural; - several arms, each arm extending radially from the central compartment through the auxiliary channel, the first portion of the discharge conduit extending between two arms; - the sampling port includes a variable discharge valve configured to regulate the flow rate of a stream flowing through the discharge conduit.

[0016] The invention also relates to an aircraft comprising a turbomachine according to the invention.

[0017] The turbomachine according to the invention has a reduced central compartment footprint and improved aerodynamic performance thanks to the proposed structural configuration for the discharge duct. DESCRIPTION OF THE FIGURES

[0018] Other features, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0019] Fig. 1 is a cross-sectional view of an unfaired fan turbomachine;

[0020] Fig. 2 is a detailed cross-sectional view of a prior art discharge conduit;

[0021] Figure [Fig. 3] is a detailed cross-sectional view of a discharge conduit according to a mode of realization ;

[0022] Fig. 4 is a detailed cross-sectional view of a discharge conduit according to another embodiment.

[0023] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

[0024] Figure 1 represents a turbomachine 110 according to an embodiment of the invention. The turbomachine 110 extends along an axis A and comprises two unfaired propellers 121 and 131 which together form a fan. In particular, the fan consists of the upstream unfaired propeller 121, which is free to rotate about the axis A and is located upstream of the downstream unfaired propeller 131, or fixed stator.

[0025] The turbomachine 110 also includes a main channel 171 which extends through the turbomachine 110 from upstream to downstream in a direction G of gas flow in the turbomachine, essentially parallel to the axis A, from a main inlet 170 to a main outlet 180 opening outside the housing of the turbomachine 110.

[0026] The main channel 171 is configured to circulate a primary airflow in a general gas flow direction, represented by arrow G in [Fig.1], from the main inlet 170 to the main outlet 180, which is therefore located downstream of the main inlet 170.

[0027] In the following description, the terms "radially internal" and "radially external" refer to the radial position of an element with respect to the axis A, and the terms upstream and downstream are defined with respect to the general flow direction G of the gases through the turbomachine 110.

[0028] Between the propeller and the guide vanes, i.e. downstream of an unfaired propeller 121 and upstream of the unfaired guide vanes 131, the turbomachine has in its casing the main inlet 170 of the main channel 171.

[0029] In this same embodiment of the invention, and along the main channel 171, the turbomachine 110 comprises successively in the direction G of gas flow:

[0030] - at least one compression stage 145 forming, for example, a section of compression, the compression section may include upstream a low-pressure compressor and downstream a high-pressure compressor 127,

[0031] - a combustion chamber 128.

[0032] The compression stage 145 is understood to be an assembly of a rotating blade wheel (or rotor with rotating blades) and a stationary blade wheel (or stator with stationary blades), the rotating blade wheel being able to be located upstream or downstream of the stationary blade wheel. This compression stage 145, by rotating the rotating blade wheel, can create an increase in air pressure downstream of the stage compared to the upstream of the compression stage 145.

[0033] In the main channel 171, the turbomachine 110 further comprises, downstream of the combustion chamber 128, a turbine section which may include upstream a high-pressure turbine 129, and downstream a low-pressure turbine 150. The turbomachine is also supplied with air by the main channel 171.

[0034] The main channel 171 is configured to supply air entering through the air inlet 170 to at least one compression stage 145 and the combustion chamber. More precisely, it is the air compressed by the at least one compression stage 145 that is displaced in the main channel 171 to the combustion chamber and supplies it. This supply occurs in the direction of flow G from the main inlet 170 towards the compression stages.

[0035] The turbomachine 110 also includes an auxiliary channel 173 which extends from an auxiliary inlet opening into the main channel 171 to an auxiliary outlet 178 opening outside the turbomachine 110. The auxiliary inlet is located upstream of each compression stage 145 of the main channel 171. The main channel 171 is separated from the auxiliary channel 173 by a central compartment 12 (“core compartment” in Anglo-Saxon terminology).

[0036] An external casing 13 or nacelle, radially external to the central compartment 12, surrounds the turbomachine 110 and, together with the central compartment 12, delimits the auxiliary channel 173. Thus, the auxiliary channel 173 is located radially further out than the main channel 171; that is, the main channel 171 is situated between the axis A of the turbomachine 110 and the auxiliary channel 173. The auxiliary channel 173 may have an annular shape and extend around the axis A of the turbomachine 110, between the central compartment 12 and the external casing 13. The air outlet 178 is located downstream of the guide vanes 131 and upstream of the main outlet 180.

[0037] In order to impart greater rigidity to the turbomachine 110, at least one arm 33, preferably several arms 33, connect a radially external face 121 of the central compartment 12 to a radially internal face 131 of the outer casing 13. These arms 33 extend radially with respect to the axis A and are therefore arranged transversely across the auxiliary channel 173. Each arm 33 performs a structural function and ensures the relative positioning of the outer casing 13 with the central compartment 12. In addition, the central compartment 12 is traversed longitudinally by at least one structural beam 4, in order to increase its stiffness. In other words, the structural beam(s) 4 are preferably parallel to the axis A, or substantially parallel to the axis A and follow the radially external face 121 of the central compartment 12.Alternatively, the structural beams 4 can be located at least partially outside the central compartment 12, i.e. they protrude from the radially external wall 121 into the auxiliary channel 173, thus occupying less space in the central compartment 12.

[0038] Still in the same embodiment of the invention illustrated in [Fig. 1], the turbomachine 110 may include at least one heat exchanger 174 located in the auxiliary channel 173. The heat exchanger 174 is configured to be cooled by the air flowing through the auxiliary channel 173. The heat exchanger 174 may, in particular, be used to provide cooling for a gearbox configured to drive the upstream propeller 121. Various heat exchanger technologies can be considered, such as volumetric exchangers, surface exchangers, finned exchangers, etc.

[0039] According to this same embodiment, the turbomachine 110 comprises a discharge conduit 2 opening into the main channel 171, i.e., a sampling port 21 of the discharge conduit 2 opens onto the main channel 171 and is located downstream of at least one compression stage situated in the main channel 171. The discharge conduit 2 thus extends outwards from the main channel 171, through the central compartment 12, and opens into the auxiliary channel 173. More precisely, the discharge conduit 2 comprises a first portion 221 formed in the central compartment 12 and a second portion 222 formed in a structural beam 4. This arrangement makes it possible to reduce the overall size of the central compartment 12.At one end of the second portion 222, the discharge conduit 2 opens into an air outlet 22 in the auxiliary channel 12, so as to conduct a portion of the gases from the primary airflow passing through the main channel 171 to the auxiliary channel 173. Preferably, a variable discharge valve 176 is disposed in the sampling mouth 21 and is configured to regulate a flow rate of a stream flowing through the discharge conduit 2.

[0040] The air outlet 22 is located downstream of the heat exchanger 174 and preferably has an ejection angle of less than 60° with respect to the radially external face 121 and the direction of gas flow G. Thus, this configuration, in addition to saving space, allows for a reduction in turbulence compared to the prior art illustrated [Fig.2], firstly due to a greater distance between the air outlet 22 and the heat exchanger 174 and secondly due to a lower ejection angle, made possible by the arrangement of the second portion 222 in the structural beam 4. This increases the aerodynamic performance of the turbomachine 110.

[0041] In a second embodiment, illustrated [Fig.3], the structural beam 4 is positioned opposite arm 33, with the first portion 221 of discharge conduit 2 passing through arm 33 to ensure continuous flow. Preferably, structural beam 4 is bolted to arm 33 to ensure continuity of mechanical forces. Even more preferably, a sealing gasket 35 is placed at an interface 36 between arm 33 and structural beam 4, the sealing gasket 35 ensuring a seal between the first portion 221 and the second portion 222 of discharge conduit 2, so that no gas loss occurs between discharge conduit 2 and the central compartment 12. Advantageously, the sealing gasket 35 is resistant to high temperatures and fire to limit the spread of fire in the turbomachine 110.

[0042] Alternatively, in a third embodiment illustrated [Fig.4], the first portion 221 of the discharge conduit 2 extends between two arms 33, which represents a simpler configuration and allows more space to be preserved at the level of the arms 33.

[0043] Of course, the embodiments detailed in this presentation are adaptable to a triple-flow turbomachine, the auxiliary channel 173 then being understood as the channel in which the tertiary flow circulates.

Claims

Demands

1. Turbomachine (110) comprising: - a main channel (171) configured to supply at least one compression stage (145) with air, - an auxiliary channel (173) separated from the main channel (171) by a central compartment (12), the main channel (171) and the auxiliary channel (173) extending about an axis (A) extending from upstream to downstream in a direction of air flow (G) in the turbomachine (110), - a discharge duct (2) extending in the central compartment (12) from a sampling port (21), opening into the main channel (171), to an air outlet (22) opening into the auxiliary channel (12), the sampling port (21) being configured to draw air from the main channel (171), the discharge duct (2) comprising a first portion (221) formed in the central compartment (12) and a second portion (222) formed in a structural beam (4) of the central compartment (12),the structural beam (4) extending along the auxiliary channel (173) and being adapted to impart rigidity to the central compartment (12), the discharge duct (2) being adapted to draw air from the main channel (171) and bring it to an auxiliary channel (173).

2. Turbomachine (1) according to claim 1, comprising an arm (33) extending radially from the central compartment (12) through the auxiliary channel (173), the structural beam (4) being arranged opposite the arm (33), the first portion (221) of the discharge conduit (2) then passing through the arm (33).

3. Turbomachine (110) according to claim 2, wherein the structural beam (4) is fixed to the arm (33) by means of bolts.

4. Turbomachine (110) according to any one of claims 2 or 3, comprising a sealing gasket (35) placed at an interface (36) between the arm (33) and the structural beam (4).

5. Turbomachine (110) according to claim 1, comprising several arms (33), each arm extending radially from the compartment 9 central (12) through the auxiliary channel (173), the first portion (221) of the discharge conduit (2) extending between two arms (33).

6. Turbomachine (110), according to any one of claims 1 to 5, wherein the intake port (21) includes a variable discharge valve (23) configured to regulate a flow rate of a stream flowing through the discharge conduit (2).

7. Aircraft comprising a turbomachine (110) according to any one of the preceding claims.

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