FR3042554A1 - SHIRT COMPRISING A COOLING DUCT FOR TURBOMACHINE CUP - Google Patents

Abstract

The invention relates to a piston (2) and a hollow body (3) in which the piston (2) is configured to slide. The interior of the hollow body (3) comprises a first chamber (31) and a second chamber (32) separated from the first chamber (31) by the piston (2). The hollow body (3) comprises a side wall (34) at least partially surrounding the first chamber (31) and the second chamber (32). The interior of the hollow body (3) further comprises a jacket (6), located between the side wall (34) and the piston (2), comprising at least one cooling duct (7) fluidly connecting the first chamber (31). ) and the second chamber (32).

Description

SHIRT COMPRISING A COOLING PIPE FOR VERIN DE

TURBOMACHINE

DESCRIPTION

TECHNICAL FIELD The invention relates to the general technical field of aircraft turbomachines. More specifically, the invention relates to an assembly for providing mechanical power to turbomachine equipment.

STATE OF THE PRIOR ART

FIG. 1 represents a hydraulic assembly 1 for a turbomachine, configured to supply mechanical power to turbine engine equipment. Such a set is for example known from patent application FR 2 957 999 from Snecma. The assembly 1 comprises a piston 2 sliding in a hollow body 3. The piston 2 comprises a first face 21 and a second face 22 opposite the first face 21. The piston 2 is traversed by a channel 23 which opens on the first face 21 on the one hand and on the second side 22 on the other.

The channel 23 comprises a flow restrictor 24, allowing the circulation of a leakage flow through the piston 2. This restrictor 24 takes for example the shape of bends of the channel 23. The restrictor 24 limits the decrease in the mechanical performance of all, resulting from the flow of the leakage flow in the channel 23.

The leakage rate is useful for cooling the assembly 1, in particular in the event of a fire in the turbomachine. The mechanical performance of the piston 2 is nevertheless degraded by the presence of the leakage rate in the channel 23.

There is therefore a need to cool a turbomachine assembly, configured to provide mechanical power, while increasing the mechanical performance of the assembly and / or decreasing the diameter of the piston.

DISCLOSURE OF THE INVENTION The invention aims to at least partially solve the problems encountered in the solutions of the prior art. In this regard, the invention relates to a turbomachine assembly, comprising a piston and a hollow body in which the piston is configured to slide. The interior of the hollow body includes a first chamber and a second chamber separated from the first chamber by the piston. The hollow body includes a side wall at least partially surrounding the first chamber and the second chamber.

According to the invention, the interior of the hollow body further comprises a jacket, located between the side wall and the piston, comprising at least one cooling duct fluidly connecting the first chamber and the second chamber.

The conduit that passed through the piston is offset at the level of the shirt. The conduit makes it possible to reduce the diameter of the piston with equivalent mechanical performance of the assembly, while allowing cooling of the assembly by the circulation of a leakage flow rate in the conduit.

It is at least as easy to make the cooling duct in the jacket as in the piston. It is generally easier and less expensive to arrange the cooling duct in the jacket rather than in the side wall of the hollow body. The assembly may optionally comprise a cooling duct in the hollow body, in addition to the cooling duct of the jacket. The invention may optionally include one or more of the following features combined with one another or not.

Advantageously, the liner is made of metallic material, preferably in the same material as the hollow body.

The surface of the jacket intended to be in contact with the piston may be treated or comprise a coating, in order to reduce the friction and the wear that results therefrom.

According to a particular embodiment, the liner is removable relative to the assembly. The shirt can be changed easily in case of excessive wear. In particular, the change of the liner makes it possible to limit the subsequent machining or the replacement of the hollow body.

According to an advantageous embodiment, the liner extends along the side wall at least over the entire length of maximum stroke of the piston.

Preferably, the cooling duct takes the form of a channel open only on the side wall over substantially the majority of the channel length, preferably at least three quarters of the length of the channel.

This configuration makes it easier to control the leakage flow flowing from the second chamber to the first chamber.

According to another advantageous embodiment, the cooling duct is of substantially constant section.

According to an advantageous embodiment, the first chamber and the second chamber are configured to contain a liquid capable of degrading beyond 100 ° C, such as oil or fuel.

The circulation of a leakage flow at high temperature limits the stagnation of the fluid and the degradation of the fluid that results. Oil and fuel being flammable, it is also important to maintain the tightness of the whole in case of fire. The circulation of the leakage flow makes it possible to cool the assembly and to keep it tight, especially at the level of the seals of the assembly.

Advantageously, the assembly comprises a first fluid orifice opening into the first chamber, and a second orifice opening into the second chamber. The first port is configured to supply the first fluid chamber. The second port is configured to supply the second chamber with fluid. The cooling duct is preferably located in the side wall, diametrically opposite the first orifice and the second orifice.

The side wall portion opposite the first orifice and the second orifice may be subjected to particularly high temperatures in the event of a fire in the turbomachine. The location of the duct at this location allows to effectively cool the hollow body.

The cooling duct preferably has a substantially helical shape. A helical shape particularly promotes a more homogeneous cooling of a cylindrical hollow body. The invention also relates to a turbomachine comprising an assembly as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood on reading the description of exemplary embodiments, given purely by way of indication and in no way limitative, with reference to the appended drawings in which: FIG. 1 is a partial schematic representation of a hydraulic assembly for a turbomachine according to an embodiment known from the state of the art, intended to supply mechanical power to turbomachine equipment; FIG. 2 is a partial schematic representation of a hydraulic assembly for a turbomachine, according to a first embodiment of the invention, in which the piston is in the "outgoing rod" position; Figure 3 is a partial schematic representation of the assembly of Figure 2, wherein the piston is in "retracted stem" position; FIG. 4 is a partial schematic representation of a hydraulic assembly for a turbomachine, according to a second embodiment of the invention, in which the piston is in the extended rod position; Figure 5 schematically shows the cooling duct fluidly connecting the first chamber and the second chamber in the liner of the assembly of the second embodiment.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

Identical, similar or equivalent parts of the different figures bear the same numerical references so as to facilitate the passage from one figure to another.

Figures 2 to 5 show an assembly 1 for a turbomachine, configured to provide mechanical power to equipment (not shown) of a turbomachine. Set 1 is a mechanical actuator for a turbomachine, such as a turbomachine hydraulic cylinder associated with a servovalve, an adjustable compressor discharge valve, a transient compressor discharge valve, or an adjustable airflow valve for set a game at the top of a turbine rotor blade. The assembly 1 comprises a piston 2 and a hollow body 3 in which the piston 2 is configured to slide. The fluid flowing in the assembly 1 and pressurized by the piston 2 is oil or fuel.

The piston 2 is fixed to a rod 9. The piston 2 and the rod 9 form a single piece which is slidably mounted in the hollow body 3. The piston 2 and the rod 9 are substantially symmetrical with revolution.

The hollow body 3 consists in particular of a single lateral wall 34 which is substantially cylindrical about the axis of the piston 2. The interior of the hollow body 3 comprises a first chamber 31 delimited by a bottom 33, and a second chamber 32 separated from the first chamber 31 by the piston 2.

The first chamber 31 and the second chamber 32 are completely surrounded by the side wall 34, with the exception of a first orifice 10 and a second orifice 12 formed in the side wall 34.

The first orifice 10 opens into the first chamber 31. The first chamber 31 is capable of being supplied with fluid by the first orifice 10 or of discharging fluid through the first orifice 10.

The second orifice 12 opens into the second chamber 32. The second chamber 32 is capable of being supplied with fluid by the second orifice or of discharging fluid through the second orifice 12. The assembly 1 also comprises a drainage channel 14 at a distance along the hollow body 3 of the first chamber 31 and the second chamber 32. The drainage channel 14 serves to drain out of the assembly 1 the fluid located between a first seal 17 and a second seal 19. The channel drainage 14 is located between these two seals 17,19. The seal between the piston 2 and the hollow body 3, during the displacement of the piston 2 relative to the hollow body 3, is provided the seals 15,17,19. These seals 15,17,19 are substantially of revolution around the piston 2 and the rod 9. It is all the more important that there is no leakage out of the hollow body 3 that the fluid is a flammable liquid. . The assembly 1 also comprises a sensor configured to determine the position of the piston 2 relative to the hollow body 3. This sensor is in particular a sensor 5 for measuring the displacement of the piston along the axis of a sensor bar 8. The sensor 5 is for example a passive two-way linear displacement electric sensor. Such a sensor is also known as the "LVDT sensor".

Still referring to Figures 2 to 5, the interior of the hollow body 3 comprises a jacket 6 located between the side wall 34 and the piston 2. The piston 2 slides along the side wall 34 inside the jacket 6. The length of the liner 6 is greater than or equal to the maximum stroke length of the piston 2.

The jacket 6 consists of a single piece of metal material. This material is identical to the material of the hollow body. The surface of the jacket 6 is coated by hard anodic oxidation to limit its wear due to friction with the piston 2.

The liner 6 is immobilized with respect to the hollow body 3, during operation of the assembly 1.

The liner 6 is nevertheless removable relative to the hollow body 3, so as to be separated from the hollow body 3 and replaced by a new liner 6, when the liner 6 is damaged and in particular when it is worn.

The jacket 6 comprises a cooling duct 7 fluidly connecting the first chamber 31 and the second chamber 32.

The piston 2 is devoid of channel 23 passing therethrough. A fortiori, the flow restrictor 24 present in the channel 23 of the piston 2 is also eliminated with respect to the embodiment of FIG. 1. The duct 7 serves to discharge a cooling flow rate between the second chamber 32 and the first chamber. 31, replacing the channel 23 shown in FIG.

The cooling duct 7 takes the form of an open channel only on the side wall 34 over substantially the majority of the channel length, preferably at least three quarters of the length of the channel.

The conduit 7 is of constant section. The duct 7 has a diameter greater than 0.4 mm, to limit the obstruction of the duct 7 by the residues present in the fluid. The diameter of the duct is for example equal to 0.52 mm and its length to 57 mm.

The manufacture of the duct 7 is all the easier as it is of constant section and is made in the jacket. The manufacture of the duct 7 is further facilitated, when it is in the form of a groove formed on one of the walls of the liner 6.

Referring more specifically to Figure 2, the cooling duct 7 takes the form of a groove formed on a portion of the outer surface of the liner 6. The duct 7 extends along the side wall 34 substantially rectilinear over at least the majority of its length, preferably at least three quarters of its length.

This duct 7 is located in the liner 6, diametrically opposite the first orifice 10 and the second orifice 12. In FIG. 2, the piston 2 is represented as an outgoing rod, in which the piston 2 is at a distance from the bottom of the piston. second chamber 32 and the sensor 5. The piston 2 is at a distance from the first orifice 10 and the second orifice 12.

With reference to FIG. 3, the piston 2 is in a retracted rod position. The piston 2 is closer to the displacement sensor 5. The piston 2 remains at a distance from the second orifice 12 and the first inlet of the duct, so that fluid can continue to circulate in the duct 7.

In general, the assembly is configured so that the piston 2 remains at a distance from both the first orifice 10, the second orifice 12 and the conduit entries.

The piston 2 moves from the extended stem position shown in FIG. 2 to the retracted stem position shown in FIG. 3, when the mechanical forces exerted on the rod 9 from the outside of the assembly and the fluid pressure forces in the first chamber 31 on the one hand are greater than the fluid pressure forces in the second chamber 32 on the other.

The temperature of the fluid in the first chamber 31 remains substantially equal to the temperature of the fluid in the second chamber 32, during the displacement of the piston 2. The flow of the leakage flow through the conduit 7 makes it possible to avoid the degradation of the fluid at high temperature, typically at a temperature above 100 ° C, or 160 ° C, facilitating the flow of fluid.

This flow also allows to properly cool the assembly 1 in case of fire using the fluid as heat transfer fluid. The location of the conduit diametrically opposite the first orifice 10 and the second orifice 12 makes it possible to cool the side wall 34 more effectively. The flow of the leakage flow through the duct 7 also allows the assembly 1 to be suitably cooled in case fire. The cooling rate is a permanently leakage rate. The leak rate is likely to vary.

FIG. 4 represents a second embodiment of the invention which differs from the first embodiment, in that the duct 7 has a substantially helical shape. The pitch of the helix is between 5% and 90% of the length of the jacket 6.

The pitch of the helix is preferably constant but it can vary, for example so that the turns of the helix are closer together in the areas that need the most cooling.

The duct 7 is designed as a groove of constant width on the outer surface of the liner 6. This outer surface is intended to face the side wall 34.

The body of the liner 61 is a cylindrical envelope about an axis 63 intended to match the shape of the side wall 34. The axis 63 coincides with the axis of the hollow body 3, when the liner 6 is attached to the body hollow 3.

In general, the liner 6 may also be made of a material different from that of the hollow body 3. The liner 6 may also comprise no surface coating.

The cooling duct 7 is preferably made over most of its length on the outer surface of the liner. It is understood that the cooling duct opens on the inner surface of the jacket, to allow the flow of fluid between the first chamber 31 and the second chamber 32.

Alternatively, the cooling duct 7 could also be made over most of its length inside the liner or on the inner surface of the liner.

The duct 7 performs the function of restricting the flow flowing between the second chamber 32 and the first chamber 31, because of its long length and its reduced diameter. In this regard, the ratio of the length of the duct 7 to its average diameter is for example between 7 and 10 per thousand.

The width of the duct may vary along the duct.

In any case, the greater length of the duct 7 relative to that of the channel 23 offers the possibility of eliminating the more complex shape restrictor of the state of the art and / or protection systems against pollutant particles. which were likely to clog the channel 23.

According to an alternative embodiment (not shown), the conduit 7 could comprise one or more narrowing, at least one, serving as a flow restrictor in the conduit. The diameter of the narrowed portions of the duct preferably remains greater than 0.4 mm to prevent them from clogging too quickly with pollutants present in the fluid.

According to another alternative embodiment (not shown), the conduit 7 may comprise at least punctually flow restrictors in the form of reliefs.

As a further variant (not shown), the duct 7 is of constant section but has at least one elbow, preferably a plurality of elbows which also provide a flow restrictor function.

These three alternative embodiments not shown allow to increase the average section of the duct, because of the presence of the restrictor flow.

In general, the location of the duct 7 makes it possible to limit the decrease in mechanical performance of the piston 2 generated by the leakage flow. The deportation of the duct 7 out of the piston makes it possible either to increase the power of the piston 2 to constant diameter, or to reduce the diameter of the piston 2 constant power.

Claims (10)

Turbomachine assembly, comprising: a piston (2), a hollow body (3) in which the piston (2) is configured to slide, the interior of the hollow body (3) comprising: a first chamber (31), a second chamber (32) separated from the first chamber (31) by the piston (2), the hollow body (3) comprising a side wall (34) at least partially surrounding the first chamber (31) and the second chamber (32). ), characterized in that the interior of the hollow body (3) further comprises a jacket (6), located between the side wall (34) and the piston (2), comprising at least one cooling duct (7) connecting fluidly the first chamber (31) and the second chamber (32). 2. Assembly according to the preceding claim, wherein the jacket (6) is made of metal material. 3. An assembly according to any one of the preceding claims, wherein the liner (6) is removable relative to the assembly. 4. An assembly according to any one of the preceding claims, wherein the liner (6) extends along the side wall (34) at least over the entire length of maximum stroke of the piston (2). 5. An assembly according to any one of the preceding claims, wherein the cooling duct (7) takes the form of a channel open only on the side wall (34) over substantially the majority of the length of the channel, preferably on at least three quarters of the length of the canal. 6. An assembly according to any one of the preceding claims, wherein the cooling duct (7) is of constant section. 7. An assembly according to any one of the preceding claims, wherein the first chamber (31) and the second chamber (32) are intended to contain a liquid capable of degrading at a temperature above 100 ° C, such that oil or fuel. 8. An assembly according to any one of the preceding claims, comprising: a first orifice (10) opening into the first chamber (31), the first orifice (10) being configured to supply the first chamber (31) with fluid, a second orifice (12) opening into the second chamber (32), the second orifice (12) being configured to supply the second chamber (32) with fluid, the cooling duct (7) being located in the lateral wall (34), diametrically opposed to the first port (10) and the second port (12). 9. Assembly according to any one of claims 1 to 7, wherein the cooling duct (7) has a substantially helical shape. 10. Turbomachine comprising an assembly according to any one of the preceding claims.