Oil nozzle for turbomachine

Abstract

Oil nozzle for turbomachine One aspect of the invention relates to an oil nozzle (200) for lubricating components such as bearings within a turbomachine, comprising: a main oil supply duct (210), at least one secondary oil outlet duct (220) through which the oil is sprayed onto the component, and a connection zone (230) of the secondary duct to the main duct comprising a junction angle (260) between the main duct and the secondary duct, characterized in that the connection zone (230) comprises an internal wall (235) in contact with the oil, said internal wall (235) being at least partially curved at the junction between the secondary duct and the main duct so that the junction angle (260) inside the connection zone is at least partially rounded. Another aspect of the invention relates to a turbomachine equipped with at least one such oil nozzle.Figure to be published with the abstract: Figure 4.

Description

Title of the invention: Oil nozzle for turbomachine TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an oil nozzle for a turbomachine and in particular to an oil nozzle intended to spray oil to lubricate and / or cool components such as the bearings of a turbomachine. It also relates to a turbomachine equipped with at least one such oil nozzle.

[0002] The invention finds applications in the field of aeronautics and, in particular, in the field of lubrication of aeronautical engine parts such as turbomachine bearings. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] It is known, in aeronautics, to spray oil onto certain parts of turbomachines in order to lubricate and / or cool them. In particular, in a turbomachine, the components such as bearings, gears, electric generators, etc., are lubricated by means of an oil circulating in an oil circuit and injected by an oil nozzle towards the components to be lubricated, in an engine enclosure.

[0004] An example of a turbomachine engine enclosure is shown in [Fig. 1]. This [Fig.l] shows a motor shaft 10 around which bearings 20 are mounted, providing a mechanical connection between the rotor and the stator of the engine. A first enclosure 30 surrounds the bearings 20 and ensures the circulation of the oil. A second enclosure 40 surrounds the first enclosure and ensures the pressurization of the oil within the first enclosure 30. In this example, the oil is sprayed towards the bearings 20, within the first enclosure 30, by an oil jet, represented schematically by the reference 100. The oil thus sprayed onto the bearings flows into the first enclosure 30 and is discharged by gravity into the collection conduit 35 to be recycled and / or reinjected into the oil circuit.

[0005] To be effective, the components, for example the bearings, must be lubricated homogeneously with an oil distributed as uniformly as possible over said components. However, the behavior of the oil jet projected onto the components to be lubricated of the engine varies depending on the flight phases of the aircraft. Indeed, in flight, the shaft of the turbomachine rotates at speeds which vary according to the flight phase. When the rotational speed of the shaft is high, the rotational movement of the shaft induces air flows which can have an effect on the behavior of the injected oil jet, such as for example deflecting the oil jet. However, a deflection of the oil jet results in less precise and less dynamic targeting. The oil jet may not reach the targeted component or only reach a part of the component to be lubricated, which has a direct effect on the operation of the engine and the service life of the component.

[0006] In the field of aeronautics, oil nozzles are often formed from a conduit or a set of conduits made by drilling a raw part. An example of an oil nozzle is shown in section in [Fig.2]. In this example, the oil nozzle comprises a main conduit 110, for example a portion of an oil circuit, and a secondary conduit 120 connected to the main conduit. The secondary conduit 120, of a length L and a diameter D, comprises a first end 120a connected to the main conduit and a second open end 120b, through which the oil, under the effect of pressure, is projected towards the member to be lubricated.

[0007] Since current nozzles are manufactured by multiple drilling, protruding angles are created in the connection areas of the conduits, forming sharp edges between two drillings, at the intersection of the conduits. These edges produce instability of the oil flow. For example, in the connection areas, the oil flow can produce a separation, which causes a low pressure zone that can generate cavitation and / or destabilize the oil jet by amplifying disparities in the oil flow. The oil flow is then no longer symmetrical, which can cause atomization of the oil jet, i.e. a breakup of the jet into a diffuse spray.

[0008] [Fig. 3] shows a diagram showing an example of pressure differences within a conventional oil nozzle. In this example, the oil flow circulates in the main conduit 110 with a pressure PI then enters the secondary conduit 120 with a pressure which changes within said secondary conduit. The pressure PI at the inlet of the secondary conduit 120, in particular in the upper part of the connection zone 130, changes towards a pressure P2 in the vicinity of the lower part of the connection zone 130. This pressure difference between the different portions of the secondary conduit 120 generates, in this example, a vortex release LT (having a pressure P3) and a depression zone DP (having a pressure P4) in said secondary conduit. The oil flow in the secondary conduit 120 is therefore unstable and this instability is reflected in the entire oil flow, even after it leaves said secondary conduit.Indeed, the oil jet, after the outlet 140 of the nozzle 100, has pressure variations VP which induce a poor quality of the oil jet, such as a bursting into a diffuse spray, called atomization. However, an atomized oil jet is not only a non-coherent jet, therefore of poor quality, but in addition it is particularly sensitive to air flows and can therefore easily be deflected, generating poor targeting of the organs to be lubricated.

[0009] It is known, in the field of aeronautics, to attempt to remedy the problems of instability of the oil flow and atomization of said oil jet at the nozzle outlet, by increasing the L / D ratio of the oil nozzle because, the higher the L / D ratio, the more time the oil flow has to stabilize before leaving the nozzle. However, increasing the L / D ratio has a direct impact on the sizing of the nozzle which then presents a larger footprint.

[0010] However, nowadays, the environment within turbomachines is increasingly constrained, which requires reducing the size of the various parts and components within the turbomachines and, in particular, the size of the nozzles. The solutions proposed to date are therefore contrary to the evolution of turbomachines.

[0011] There is therefore a real need for an oil nozzle allowing the projection of a stable jet of oil, that is to say an oil jet which, at the time of its projection towards the organs to be lubricated, is free from any depression and / or imbalance, without the size of said nozzle being increased. Summary of the invention

[0012] To address the problems mentioned above of instability of the oil jet at the nozzle outlet, the applicant proposes an oil jet for the lubrication of turbomachine components whose internal wall of the connection zone is curved and free of angularities.

[0013] According to a first aspect, the invention relates to an oil nozzle for lubricating components such as bearings within a turbomachine, comprising: • a main oil supply duct, • at least one secondary oil outlet duct through which the oil is sprayed onto the component, and • a connection zone of the secondary conduit on the main conduit comprising a junction angle between the main conduit and the secondary conduit, characterized in that the connection zone comprises an internal wall in contact with the oil, said internal wall being at least partially curved at the junction between the secondary conduit and the main conduit so that the junction angle inside the connection zone is at least partially rounded.

[0014] Due to the absence of angularity at the junction between the main conduit and the secondary conduit, this nozzle allows smooth circulation of the oil flow, which reduces the risks of unsteady phenomena of the oil flow in the secondary conduit and ensures a coherent oil jet at the outlet of the nozzle.

[0015] An internal wall, as opposed to an external wall, is a wall located inside conduits and therefore in contact with the oil circulating in the oil nozzle.

[0016] In addition to the characteristics which have just been mentioned in the preceding paragraph, the oil nozzle according to one aspect of the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations: • The inner wall in contact with the oil has a bulge extending over at least a portion of the circumference of the junction angle between the secondary conduit and the main conduit. • The internal wall has a shape determined according to a diameter of the secondary duct, a value of the junction angle between the main duct and the secondary duct and / or a ratio L / D, where D is the diameter of the secondary duct and L is its length. • The junction angle between the main conduit and the secondary conduit is, depending on the direction of oil flow, an obtuse angle. • The curved shape of the internal wall is obtained by additive manufacturing. • The curved shape of the internal wall is obtained by adding a piece annular fixed inside the connection area. • The curved shape of the internal wall is obtained by drilling a raw part. • The secondary conduit and / or the main conduit is made of a material flexible capable of adapting to the flow of oil circulating in said conduits, the main and / or secondary conduit made of flexible material being held by an attachment system on a structure of the turbomachine.

[0017] Another aspect of the invention relates to a turbomachine, characterized in that it comprises at least one oil nozzle as defined above. BRIEF DESCRIPTION OF THE FIGURES

[0018] Other advantages and characteristics of the invention will appear on reading the following description, illustrated by the figures in which:

[0019] [Fig.l] [Fig.l], already described, represents a schematic sectional view of an example of a turbomachine engine enclosure equipped with an oil nozzle;

[0020] [Fig.2] [Fig.2], already described, represents a schematic sectional view of a oil nozzle according to the state of the art;

[0021] [Fig.3] [Fig.3], already described, schematically represents a variation of the pressure of the oil flow within a nozzle according to the state of the art and at the outlet of said nozzle;

[0022] [Fig.4] [Fig.4] represents a schematic sectional view of an example of a nozzle of oil according to the invention;

[0023] [Fig.5] [Fig.5] represents a schematic sectional view of another example of oil nozzle according to the invention; and

[0024] [Fig.6] [Fig.6] represents, according to a schematic section, two examples of annular parts intended to be fixed in the connection zone of an oil nozzle according to the invention. DETAILED DESCRIPTION

[0025] An exemplary embodiment of an oil nozzle, configured to limit the instability of the oil flow in the secondary conduit of the nozzle, is described in detail below, with reference to the accompanying drawings. This example illustrates the characteristics and advantages of the invention. It is however recalled that the invention is not limited to this example.

[0026] In the figures, identical elements are identified by identical references. For reasons of readability of the figures, the size scales between elements represented are not respected.

[0027] An example of an oil nozzle according to the invention is shown in [Fig. 4]. This oil nozzle 200 comprises a main conduit 210, for example a portion of an oil circuit, and a secondary conduit 220 connected to the main conduit 210 in a region called the connection zone 230. The main conduit 210 and secondary conduit 220 are pipes intended to transport the oil from the oil circuit to the outlet 240 of the nozzle 200 from where it is sprayed towards the members to be lubricated. The secondary conduit 220 comprises a first end 220a connected to the main conduit 210 and a second open end 220b, through which the oil, under the effect of pressure, is sprayed towards the member to be lubricated, for example a bearing. At the junction between the secondary conduit and the main conduit, that is to say at the mouth of the secondary conduit, the connection zone 230 has an angle, called the junction angle.This angle is preferably, depending on the direction of circulation of the oil, an obtuse angle suitable for ensuring circulation of the oil with a chosen pressure.

[0028] The oil nozzle according to the invention comprises, in the connection zone 230 of the secondary conduit 220 on the main conduit 210, a curved internal wall 235, forming a rounding on at least a portion of the junction angle, inside the connection zone 230. Indeed, as shown in [Fig.4], the internal wall 235 has a curve of a predefined shape, adapted to limit or eliminate the sharp edges or angular projections inside the connection zone 230, in the vicinity of the junction angle.

[0029] According to certain embodiments of the invention, the internal wall 235 has a curved shape extending over the entire circumference of the junction angle between the secondary conduit 220 and the main conduit 210 so that the entire junction angle is rounded. In these embodiments, the junction angle no longer has any angular projection or sharp edge which could generate instability of the oil flow.

[0030] According to other embodiments, the internal wall 235 has a curved shape extending over only a part of the circumference of the junction angle between the secondary conduit 220 and the main conduit 210. In these embodiments, the curved part of the junction angle extends over the part of the junction angle having the greatest impact on the pressure of the oil at the time of entry into the secondary conduit and therefore the greatest risk of generating disturbances in the circulation of the oil flow. Thus, by limiting the angular protrusions to the areas of the junction angle least likely to create disturbances, the risks of instability of the oil flow are limited.

[0031] According to certain embodiments, the internal wall 235 comprises a bulge extending over the entire circumference of the junction between the secondary conduit and the main conduit or over only a part of this circumference. This bulge, which can be obtained by various methods described later, has the effect of covering a salient angle so that the oil is no longer in contact with said salient angle but with the bulge. These embodiments have the advantage of allowing the manufacture of the main and secondary conduits according to the conventional drilling technique, the addition of the bulge being an operation carried out subsequently on existing conduits.

[0032] In certain embodiments of the invention, the external wall of the connection zone 230, i.e. the wall which is not in contact with the oil, may also be curved with a shape identical to or different from the shape of the internal wall 235.

[0033] The fact that at least part of the junction angle between the main conduit 210 and the secondary conduit 220 is rounded, and therefore devoid of sharp edges or angular projections, facilitates the flow of oil within the nozzle, which makes it possible to avoid detachments and limit the unsteady phenomena of the oil flow in the secondary conduit 220.

[0034] Like any nozzle, the secondary duct 220 of the oil nozzle 200 has a length L and a diameter D. The detail of the curved shape of the internal wall 235, for example its curvature, can be determined as a function of the value of the junction angle, the diameter D of the secondary duct 220, the ratio L / D, etc. For example, the radius of curvature of the internal wall 235 will be less for a junction angle of 90° than for a junction angle of 120°. An optimal shape of the internal wall 235 can be determined by topological optimization using simulation tools, for example of the CFD (Computational Fluid Dynamics) type, or by testing on a range of technological solutions. An optimal shape of the internal wall 235 can induce a minimal length L of the secondary conduit 220 and, consequently, a minimal lateral bulk of the oil nozzle.

[0035] The curved, or rounded, shape of the internal wall 235 can be obtained by different manufacturing methods. It can, for example, be obtained by additive manufacturing, by depositing one or more layers of material over and / or around the junction angle, inside the connection zone 230. Such an additive manufacturing technique makes it possible, for example, to produce a bulge or a particular shape of the connection zone.

[0036] According to another variant, the curved shape of the internal wall 235 can be obtained by adding a specific part inside the nozzle, in the connection zone 230. An example of a nozzle 200 equipped with such a specific part 250 is shown schematically in [Fig. 5]. This specific part 250 can be an annular part, or channel, housed in the secondary conduit 220, at the intersection with the main conduit 210, at the location of the junction angle. This annular part 250 can be presented, as in example A of [Fig. 6], in the form of a crown comprising a flat external face 250a, intended to be in contact with the internal face 220b of the secondary conduit 220 and a curved internal face 250b, intended to be in contact with the oil flow. Alternatively, the annular part 250 may be presented, as in example B of [Fig.6], in the form of a half-crown comprising a flat external face 250a, intended to be in contact with the internal face 220b of the secondary conduit 220, a curved internal face 250b, intended to be in contact with the oil flow, and a flat transverse face 250c forming the outlet face of the nozzle. This annular part can be fixed inside the connection zone 230 by any fixing means known in the field, such as for example by welding, brazing or screwing.

[0037] According to one embodiment of the invention, the secondary conduit 220 and / or the main conduit 210 is made of a flexible material capable of adapting to the flow of oil circulating in said conduits and having good heat resistance. The flexible material has the advantage of having a curved junction, without any angularity. In this embodiment, the conduit(s) made of flexible material is held by an attachment system mounted on a surrounding structure, such as for example a casing of the engine enclosure.

[0038] Whatever the embodiment of the nozzle according to the invention, the smoother the flow of oil at the points of change of direction, i.e. in the connection zone 230, is, without roughness or angularity, the more the risks of detachments and disturbances are reduced, which ensures a stable flow of the oil flow in the secondary conduit 220 and therefore a coherent jet at the outlet 240 of the nozzle. Consequently, the phenomena of atomization and / or poor targeting are very significantly reduced, or even eliminated. The secondary conduit 220 of the oil nozzle according to the invention can therefore have a shorter length L than in conventional nozzles since this length is no longer necessary to stabilize the oil flow before it leaves the nozzle.

[0039] Although described through a number of examples, variants and embodiments, the oil sprayer according to the invention includes various variants, modifications and improvements that will be apparent to a person skilled in the art, it being understood that these variants, modifications and improvements are part of the scope of the invention.

Claims

Claims

1. Oil nozzle (200) for lubricating components such as bearings within a turbomachine, comprising: - a main oil supply duct (210), - at least one secondary oil outlet duct (220) through which the oil is sprayed onto the component, and - a connection zone (230) of the secondary duct to the main duct comprising a junction angle (260) between the main duct and the secondary duct, characterized in that the connection zone (230) comprises an internal wall (235) in contact with the oil, said internal wall (235) being at least partially curved at the junction between the secondary duct and the main duct so that the junction angle (260) inside the connection zone is at least partially rounded,said internal wall (235) comprising a bulge (250) extending over at least a portion of the circumference of the junction angle between the secondary conduit (220) and the main conduit (210).,

2. Oil nozzle according to claim 1, characterized in that the internal wall (235) has a shape determined as a function of a diameter of the secondary conduit (220), a value of the junction angle (260) between the main conduit and the secondary conduit and / or a ratio L / D, where D is the diameter of the secondary conduit and L is its length.

3. Oil nozzle according to any one of claims 1 to 2, characterized in that the junction angle (260) between the main conduit (210) and the secondary conduit (220) is, in the direction of flow of the oil, an obtuse angle.

4. Oil nozzle according to any one of claims 1 to 3, characterized in that a curved shape of the internal wall (235) is obtained by additive manufacturing.

5. Oil nozzle according to any one of claims 1 to 3, characterized in that a curved shape of the internal wall (235) is obtained by adding an annular part fixed inside the connection zone.

6. An oil nozzle according to any one of claims 1 to 3, characterized in that a curved shape of the inner wall (235) is obtained.

7. by drilling a raw part. Turbomachine, characterized in that it comprises at least one oil nozzle (200) according to any one of claims 1 to 6.

Images