Venturi drainage assembly for turbomachine

Abstract

Venturi drainage assembly for a turbomachine The drainage assembly (15) comprises a nozzle arm (11) contained in a nozzle (9) through which combustion gases circulate, a drain collector (16) collecting the fluids drained from the turbomachine (1), a Venturi ejector (17) comprising a primary channel with a constriction and a suction channel, and a conduit (18) connecting the drain collector to the inlet of the suction channel. The Venturi ejector is located in the nozzle arm (11). The inlet and outlet of the primary channel open into the nozzle so that a portion of the combustion gases passes through the primary channel and serves as a driving fluid for the ejector. The inlet of the suction channel is located on the side of the end of the nozzle arm which is directed towards the wall (13) of the nozzle. Figure to be published with the abstract: Figure 1

Description

Title of the invention: Venturi effect drainage assembly for turbomachine TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of aircraft engines such as turbomachines.

[0002] The present invention relates to a drainage assembly for a turbomachine. It also relates to a turbomachine and a method for draining associated fluids. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] In aircraft engines, particularly those of helicopters, it is often necessary to evacuate fluids of different types, such as fuel or oil, to prevent these fluids from accumulating and disrupting the operation of the engine.

[0004] These fluids, containing a large proportion of liquids and coming from different parts of the engine, are drained and collected in a collector which must be emptied to avoid any risk of untimely overflow.

[0005] This draining can conventionally be done while the aircraft is stationary and on the ground. In this case, the collector is a device external to the engine, for example a container-box located under the engine, which is accessible on the ground for the draining operation. It is then necessary to provide an interface between the drains located inside the engine and the collector located outside. This interface must be designed in consultation with the aircraft manufacturers, which is limiting for aircraft engine manufacturers.

[0006] To overcome these constraints, drainage devices integrated into aircraft engines have also been developed in the prior art, in which the collector is emptied autonomously, directly in flight.

[0007] Such a drainage device is for example described in the applicant's application FR3015567A1.

[0008] This prior art device comprises a collector, also called a drain box, which collects the fluids drained from the engine via conduits opening into the collector. These drained fluids are evacuated from the collector using pumping means or by means of an active ejector of the jet pump type placed in a conduit which connects the collector to the combustion gas exhaust nozzle.

[0009] To cause the evacuation of the fluids drained into the nozzle, pressurized air is taken from a stage of the turbomachine compressor and sent into a first duct of the ejector in order to force the suction of the fluids by the Venturi effect. drained into a second duct of the ejector opening into the nozzle.

[0010] However, the tapping of pressurized air from the compressor, necessary for the operation of this type of prior active ejector drainage device, has a significant negative impact on the performance of the engine. Indeed, this pressure tapping reduces the power of the compressor and therefore the overall efficiency of the turbomachine, which is particularly unfavorable, particularly in terms of fuel consumption.

[0011] The invention aims to propose a drainage assembly which does not have the drawbacks of prior devices. Summary of the invention

[0012] The invention offers a more advantageous solution because it is both autonomous, i.e. independent of the aircraft, and passive, i.e. without an active system for pumping or injecting compressed air.

[0013] Since the drainage assembly of the invention is passive, no bleed of pressurized air is necessary, either from the compressor or elsewhere in the engine or aircraft, and the performance of the engine or aircraft is not impacted.

[0014] For this, a first aspect of the invention relates to a drainage assembly of a turbomachine comprising a nozzle in which combustion gases circulate. The drainage assembly comprises: • a drain collector configured to collect gases and liquids drained from the turbomachine, • a Venturi effect ejector which comprises a primary channel starting with an inlet, comprising a constriction and ending with an outlet, and a secondary suction channel starting with an inlet and opening onto an outlet in the primary channel near the constriction, • a conduit connecting the drain collector to the inlet of the secondary suction channel of the Venturi effect ejector.

[0015] According to the invention, the drainage assembly also comprises a nozzle arm which is contained in the nozzle and which encloses the Venturi effect ejector, the primary channel and the secondary channel extending inside said nozzle arm.

[0016] Thus, the ejector is arranged in the very heart of the nozzle, but does not disturb or very little the flow of combustion gases which flow therein, the aerodynamic impact of the ejector being almost limited to that of the nozzle arm. The flow of combustion gases in the nozzle towards the exhaust is therefore not significantly slowed down and the overall power is preserved.

[0017] Furthermore, the performance of the ejector is not impacted by the wake of the arms of nozzle, because it is part of it.

[0018] The primary channel is oriented in the direction of circulation of the combustion gases (i.e. from upstream to downstream), the inlet and outlet of the primary channel opening into the nozzle.

[0019] With such an arrangement, a portion of the combustion gases flowing through the nozzle spontaneously enters and passes through the primary channel of the ejector, thus acting as a driving fluid for the ejector. It is therefore not necessary to draw compressed air from the compressor.

[0020] Furthermore, as soon as the turbomachine is in operation and whatever the engine speed and the external conditions, the speed of the combustion gases in the nozzle is very high, particularly in the upstream part of the nozzle where the nozzle arm in which the ejector is located is located. The suction created in the ejector is therefore sufficiently high to allow the drained fluids to be sucked in, even if they contain a significant liquid portion and despite the pressure losses due to the length of the conduit between the collector and the ejector, without any active pumping means being necessary.

[0021] The drain collector drains correctly regardless of the aircraft's flight phase, which prevents untimely overflows that could be detected as a failure.

[0022] The drainage assembly of the invention is therefore completely autonomous and passive.

[0023] In addition, the additional mass due to the presence of the ejector in the nozzle arm remains very low.

[0024] The drained fluids are mixed with the combustion gases at very high temperature and ejected into the nozzle where they are at least partially burned before reaching the exhaust outlet. As they are ejected in the upstream part of the nozzle, the drained fluids are already dispersed in the combustion gases when they leave the exhaust. Their impact on the fuselage of the aircraft and in particular on the tail boom is thus limited.

[0025] The inlet of the secondary suction channel is located on the side of a first end of the nozzle arm which is directed towards, and preferably fixed to, a wall of the nozzle.

[0026] Since the nozzle arm is directed towards the nozzle wall, the secondary channel can be easily connected to the duct, without posing any problem of sealing the nozzle wall and without needing an additional connecting pipe in the nozzle enclosure which would be unfavorable from an aerodynamic point of view. For this, the nozzle wall has an opening which allows the connection between the duct and the inlet of the secondary channel. Depending on the variants, the duct or the secondary channel or even an additional connecting element can pass through this opening to allow this connection.

[0027] Advantageously, when the nozzle contains several nozzle arms, the nozzle arm containing the venturi effect ejector may be the one whose first end is directed towards the wall of the nozzle at the lowest level relative to the other nozzle arms.

[0028] As the drain collector is located under the engine to collect fluids drained by gravity, the choice of this nozzle arm makes it possible to minimize the length of the conduit connecting the collector to the ejector, which reduces pressure losses and limits weight and size.

[0029] Advantageously, the inlet of the primary channel may have a section whose width corresponds to at least 70%, and preferably at least 80% of the maximum width (1) of the nozzle arm which contains the Venturi effect ejector and may even be greater than the maximum width of the arm.

[0030] The inlet of the primary channel is thus large, which makes it possible to obtain a high flow rate of the working fluid in the primary channel and therefore better suction in the secondary channel, particularly useful for sucking up liquids.

[0031] Due to the integration of the ejector in a nozzle arm which is a relatively wide device, it is possible to produce a primary channel with a large inlet without the ejector being a hindrance to aerodynamics.

[0032] Advantageously, the primary channel may terminate at its inlet and / or outlet with a flared portion, for example in the shape of a cone with a round or oval section. Such a shape improves the capture and / or ejection of gases at the inlet and / or outlet of the ejector.

[0033] Advantageously, the primary channel may terminate at its inlet and / or its outlet by a portion extending beyond the corresponding wall of the nozzle arm which contains the ejector.

[0034] Such a projecting shape makes it possible to improve the capture and / or ejection of gases, but with limited disturbance of the flow of gases in the nozzle because it is located in the extension of the nozzle arm.

[0035] Advantageously, the primary channel may have, at least at its inlet, an oblong-shaped section.

[0036] Such a shape allows for better integration of the channel into the nozzle arm and a reduction in the pressure coefficient. The oblong shape, better suited to that of the arm than a round section, makes it possible to increase the size of the primary channel without modifying the external shape of the arm and disturbing the aerodynamic flow. Thus, more combustion gas enters the primary channel and the suction increases.

[0037] Advantageously, the outlet of the primary channel can be located on a lateral flank of the nozzle arm which contains the Venturi effect ejector.

[0038] The outlet is thus located further upstream in the nozzle than when it is placed at the rear of the arm. As the speed of the combustion gases is faster there, the pressure is lower, which promotes the ejection from the primary channel of the mixture containing the drained fluids to be evacuated.

[0039] Furthermore, since, due to its aerodynamic profile, the lateral flank of the arm has a much larger surface area than its rear edge, the outlet of the primary channel can be provided with a much larger section than if it were located at the rear edge without having to add a projecting shape that risks disturbing the aerodynamic flow.

[0040] Advantageously, the primary channel can be divided, after the constriction, into two branches each ending in an outlet located one on each lateral flank of the nozzle arm which contains the Venturi effect ejector.

[0041] Each of the side outlets then benefits from the advantages set out above. In addition, the device is more robust to rotation.

[0042] Indeed, due in particular to the rotation of the turbines located upstream, the flow of combustion gases in the nozzle may not be perfectly parallel to the axis of the turbomachine and therefore to the nozzle arms, but present a certain gyration. In this case, one of the sides of the nozzle arm will be subjected to a depression, while the other will be in overpressure compared to the situation in the case of axial flow of the combustion gases.

[0043] Since the outlets of the primary channel are positioned on both sides of the nozzle arm, there will always be one that is under pressure regardless of the direction of rotation of the flow. The ejection of the drained fluids will take place mainly on the side of the outlet under pressure and will therefore always be improved, without being impacted by the direction of rotation.

[0044] Advantageously, the nozzle arm containing the venturi effect ejector is an additive manufacturing product. Its manufacture is thus made easier, regardless of the complexity of the chosen embodiment.

[0045] A second aspect of the invention relates to a turbomachine comprising a drainage assembly as described previously.

[0046] A third aspect of the invention relates to a drainage method for evacuating gases and liquids drained from a turbomachine, implemented by a drainage assembly as described previously, the method comprising, during operation of the turbomachine, the following steps: • collection of gases and liquids drained into the drain collector; • passage in the primary channel of the Venturi effect ejector enclosed in the nozzle arm, of a portion of the combustion gases which circulate in the nozzle; • suction by Venturi effect of gases and liquids present in the drain collector, in the secondary suction channel of the Venturi effect ejector enclosed in the nozzle arm, via the conduit and the opening in the nozzle wall; • mixing of the sucked gases and liquids with the combustion gases passing through the primary channel and evacuation of the mixture into the nozzle through the outlet of the primary channel.

[0047] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0048] The figures are presented for information purposes only and in no way limit the invention.

[0049] [Fig.l] is a schematic sectional view of a turbomachine equipped with an example of a drainage assembly according to the invention.

[0050] [Fig.2] is an enlargement of the boxed detail of [Fig.l] illustrating more particu the nozzle arm containing the ejector and its connection.

[0051] [Fig.3] is a perspective view of a first variant of nozzle arm containing an ejector.

[0052] [Fig.4] is a longitudinal sectional view of the nozzle arm of [Fig.3] in which a conduit was further connected to the secondary suction channel.

[0053] [Fig.5] is a perspective view of a second variant of nozzle arm containing an ejector.

[0054] [Fig.6] is a cross-sectional view, seen from above and taken at the level of its primary channel, of the nozzle arm of [Fig.5]. DETAILED DESCRIPTION

[0055] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0056] In the present application, the terms "upstream" and "downstream" are defined with respect to the normal flow direction of gas through a turbomachine (the inlet upstream and the exhaust downstream).

[0057] The term "axis of the turbomachine" refers to the axis in which the turbomachine extends, corresponding to the direction of movement of the aircraft. The "axial" direction is defined relative to this axis.

[0058] The terms "top", "bottom", "lower" and "upper" are defined based on the normal orientation of the turbomachine when installed in an aircraft flying horizontally and upright.

[0059] An example of an aircraft turbomachine 1 in which the invention can be applied has been partially represented in FIGS. 1 and 2.

[0060] This turbomachine 1 comprises a gas generator 2 formed of a compressor 3 with two rotor stages 4, a combustion chamber 5 and a turbine 6, in connection with a two-stage free turbine 7. The free turbine 7 drives the main rotor by a power shaft via a gearbox (not shown).

[0061] The gases from the combustion in the combustion chamber 5 are ejected into a nozzle 9 in which they move at high speed to the exhaust.

[0062] For aerodynamic reasons, an ejection cone 10 is arranged in the upstream part of the nozzle 9. It is suspended there by a series of nozzle arms 11 which hold it in a central position. The number of nozzle arms 11 varies depending on the size and model of the turbomachine, but generally between three and twenty.

[0063] These nozzle arms 11 are regularly distributed around the ejection cone 10 and comprise a first end 12 fixed to the wall 13 of the nozzle 9 (for example by riveting) and a second end 14 fixed to the ejection cone 10 (for example by welding). These arms can be arranged radially or tangentially relative to the ejection cone 10.

[0064] The invention can be applied to any other turbomachine architecture comprising a combustion chamber, a nozzle and at least one nozzle arm.

[0065] It is preferably applied in the case where the turbomachine is a helicopter turboshaft engine or a propeller-driven aircraft turboprop.

[0066] The turbomachine 1 is equipped with a drainage assembly 15 intended to collect residual fluids (fuel, oil, water condensate, impurities, etc.) coming from the engine. These fluids always include a significant liquid portion, most often flammable.

[0067] The drainage assembly 15 comprises a drain collector 16, a Venturi ejector 17 and a conduit 18 which fluidically connects the drain collector 16 to the ejector 17. It also comprises the nozzle 9 and one of the nozzle arms 11 which encloses the ejector 17.

[0068] The drain collector 16 is a reservoir at ambient pressure, located in the lower part of the turbomachine 1 and into which all the drains 19 connected to the different parts of the engine where fluids are likely to accumulate end. The collector 16 thus receives by gravity all the fluids to be evacuated.

[0069] The conduit 18 is intended for conveying the fluids present in the drain collector 16 towards the ejector 17.

[0070] The operating principle of the ejector 17 is based on the Venturi effect.

[0071] For this, the ejector 17 comprises a primary channel 20 which begins with an inlet 21, continues with a converging portion 22 whose section gradually decreases to a constriction 23, then continues with a diverging portion 24 whose section gradually increases and ends at an outlet 25.

[0072] The primary channel 20 is designed to be crossed by the driving fluid of the ejector 17.

[0073] The ejector 17 also comprises a secondary suction channel 26 which begins with an inlet 27 and ends with an outlet 28 which opens into the primary channel 20 near the constriction 23 and for example at the level of this constriction 23.

[0074] The conduit 18 is connected to the inlet 27 of the secondary suction channel 26 of the ejector 17.

[0075] Due to the Venturi effect, when the working fluid circulates in the primary channel 20, its pressure decreases at the throttle 23 and suction is created in the secondary suction channel 26.

[0076] This suction propagates in the conduit 18 which is connected to it and up to the drain collector 16. The drained fluids which are there are sucked into the conduit 18 and conveyed towards the secondary suction channel 26 of the ejector 17 in which they enter via the inlet 27. When they reach the outlet 28, they open into the primary channel 20 where they are carried by the flow of the working fluid with which they mix. After having traveled through the diverging portion 24, the mixture of drained fluids / working fluid is ejected via the outlet 25 and thus evacuated from the ejector 17.

[0077] According to the invention, the ejector 17 is arranged in a nozzle arm 11. This may be any nozzle arm located in the nozzle 9. Advantageously, a nozzle arm 11 located in the lower part of the nozzle 9 may be chosen and preferably the one whose first end 12 is fixed furthest down (relative to the other arms) of the wall 13 of the nozzle 9. In the case of a radial arrangement of the nozzle arms 11, this may for example be an arm arranged vertically under the ejection cone 10 (“at six o'clock”).

[0078] The primary channel 20 extends inside the nozzle arm 11, preferably in a substantially axial direction, with its inlet 21 and its outlet 25 opening into the nozzle 9 and being oriented in the direction of circulation of the combustion gases. The driving fluid of the ejector 17 is thus made up of combustion gases present in the nozzle 9.

[0079] The secondary suction channel 26 is also located in the nozzle arm 11 and preferably extends generally in the longitudinal direction of the arm. Its inlet 27 is located on the side of the first end 12 of the nozzle arm 11.

[0080] The wall 13 of the nozzle 9 has an opening 29, preferably located at this level, through which it is possible to connect the conduit 18 to the inlet 27. As shown in [Fig. 2], this opening 29 may have a size barely larger than that of the conduit 18 or the channel 26 which passes through it. Its size may nevertheless be much larger and for example correspond substantially to that of the opening 36 of the end 12 of the nozzle arm 11.

[0081] As visible in Figures 3 and 5, the nozzle arm 11 preferably has a rounded upstream edge 30 and a rounded downstream edge 31 joined by two lateral flanks 32. large area.

[0082] For aerodynamic reasons, the nozzle arm 11 preferably has a longitudinal section in the shape of an elongated drop, clearly visible in FIGS. 5 and 6, with a narrow downstream edge 31 and a wider, rounded upstream edge 30, joined by two lateral flanks 32 curved towards the upstream.

[0083] Depending on the variants, the primary channel 20 may have a round ([Fig.3] and 4) or oblong ([Fig.5] and 6) shaped section.

[0084] The inlet 21 of the primary channel 20 is preferably located at the level of the upstream edge 30 of the arm 11 and its surface area is as large as possible in order to capture a maximum of combustion gases.

[0085] Advantageously, the width of the inlet 21 is greater than 70% of the maximum width (master couple) of the nozzle arm 11 which has been materialized by a double arrow referenced 1 in [Fig.5]. The width of the inlet 21 may even be greater than the maximum width 1 of the nozzle arm 11.

[0086] For this, the primary channel 20 may comprise at its inlet a projecting flared portion 33, extending upstream beyond the upstream edge 30.

[0087] Similarly, the primary channel 20 may comprise at its outlet a projecting flared portion 34, extending downstream beyond the downstream edge 31.

[0088] Depending on the shape of the primary channel 20, these flared portions 33 or 34 are preferably cone-shaped with a round ([Fig.3]) or oval ([Fig.5]) section.

[0089] Depending on the variants, the outlet 25 of the primary channel 20 may be located at the downstream edge 31 ([Fig. 3] and 4) or a lateral flank 32 ([Fig. 5] and 6) of the nozzle arm 11. In this second case, the outlet 25 is preferably flush with the lateral flank 32 concerned.

[0090] In the variant of figures 5 and 6, the primary channel 20 comprises two outlets 25 located one on each side of the nozzle arm 11, that is to say one on each lateral flank 32.

[0091] For this, after the constriction 23, the diverging portion 24 of the primary channel 20 divides into two branches 35 each leading to one of the outlets 25.

Claims

Claims

1. Drainage assembly (15) of a turbomachine (1) comprising a nozzle (9) in which combustion gases circulate, the drainage assembly (15) comprising: - a drain collector (16) configured to collect gases and liquids drained from the turbomachine, - a Venturi effect ejector (17), comprising: • a primary channel (20) starting with an inlet (21), comprising a constriction (23) and ending with an outlet (25), and • a secondary suction channel (26) starting with an inlet (27) and opening onto an outlet (28) in the primary channel (20) near the constriction (23), - a conduit (18) connecting the drain collector (16) to the inlet (27) of the secondary suction channel (26) of the Venturi effect ejector (17), - characterized in that the drainage assembly also comprises a nozzle arm (11) which is contained in the nozzle (9) and which contains the Venturi effect ejector (17),the primary channel (20) and the secondary suction channel (26) extending inside said nozzle arm (11), - in that the primary channel (20) is oriented in the direction of circulation of the combustion gases, the inlet (21) and the outlet (25) of the primary channel (20) opening into the nozzle (9), and - in that the inlet (27) of the secondary suction channel (26) is located on the side of a first end (12) of the nozzle arm (11) which is directed towards a wall (13) of the nozzle (9).,

2. Drainage assembly (15) according to claim 1, characterized in that the nozzle (9) contains several nozzle arms (11) and in that the nozzle arm (11) which contains the venturi ejector (17) is the one whose first end (12) is directed towards the wall (13) of the nozzle (9) at the lowest level relative to the other nozzle arms (11).

3. Drainage assembly (15) according to one of the preceding claims, characterized in that the inlet (21) of the primary channel (20) has a section whose width corresponds to at least 70% of the maximum width (1) of the nozzle arm (11) which contains the Venturi effect ejector (17).

4. Drainage assembly (15) according to one of the preceding claims, characterized in that the primary channel (20) ends at its inlet (21) or its outlet (25) by a flared portion (33, 34) in the shape of a cone with a round or oval section.

5. Drainage assembly (15) according to one of the preceding claims, characterized in that the primary channel (20) has at least at its inlet (21) an oblong-shaped section.

6. Drainage assembly (15) according to one of the preceding claims, characterized in that the outlet (25) of the primary channel (20) is located on a lateral flank (32) of the nozzle arm (11) which contains the Venturi effect ejector (17).

7. Drainage assembly (15) according to one of the preceding claims, characterized in that the primary channel (20) divides, after the constriction (23), into two branches (35) each ending in an outlet (25) located one on each lateral flank (32) of the nozzle arm (11) which contains the Venturi effect ejector (17).

8. Drainage assembly (15) according to one of the preceding claims, characterized in that the nozzle arm (11) containing the venturi effect ejector (17) is an additive manufacturing product.

9. Turbomachine (1) comprising a drainage assembly (15) according to one of claims 1 to 8.

10. Drainage method for evacuating gases and liquids drained from a turbomachine (1), implemented by a drainage assembly (15) according to one of claims 1 to 8, characterized in that it comprises, during operation of the turbomachine (1), the following steps: - collection of the gases and liquids drained in the drain collector (16); - passage in the primary channel (20) of the Venturi effect ejector (17) enclosed in the nozzle arm (11), of a portion of the combustion gases which circulate in the nozzle (9); - suction by Venturi effect of the gases and liquids present in the drain collector (16) in the secondary suction channel (26) of the Venturi effect ejector (17) enclosed in the nozzle arm (11), via the conduit (18); mixing of the sucked gases and liquids with the combustion gases passing through the primary channel (20) and discharge of the mixture into the nozzle (9) through the outlet (25) of the primary channel (20).

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