Mechanical sealing structure for air turbine component of hypersonic aircraft
Technical Field
The invention relates to the technical field of mechanical sealing, in particular to a mechanical sealing structure for an air turbine component of a hypersonic aircraft.
Background
At present, with the development of aerospace technology, the requirement of human beings on the limit speed of an aircraft is increased day by day, and a hypersonic aircraft becomes a research hotspot and a introduction in the aerospace field. In the development process of hypersonic flight vehicles, the propulsive power technology is the most critical technical support. When the design speed of the aircraft is higher than Mach 3, the traditional turbojet or turbofan engine cannot be used as a power source, and the turbine-stamping combined cycle becomes the mainstream scheme of the current hypersonic power. However, since the ramjet has no rotating parts, the conventional scheme of driving the generator to generate electricity through the rotating shaft of the engine cannot be adopted, and therefore, it becomes one of the alternatives to drive the air turbine to do work by expansion by using high-speed incoming flow when the aircraft flies at high speed to generate electricity.
The high flight mach number brings ultra-high heat load to the engine and the air turbine power generation device, and puts extremely high requirements on the heat protection of the engine and the air turbine power generation device. Since no cooling air is supplied as a heat sink, air/oil path insulation and oil immersion cooling are preferred to ensure reliable operation of the rotor bearing and generator of the air turbine in relatively low temperature environments, but this also presents new challenges for mechanical sealing of the oil-gas interface. At the interface of the turbine rotating and static system, high-temperature gas working media in the meridian flow channel invade the cavity of the turbine rotating and static disc, so that a high-temperature environment exists in the cavity, and the conventional rubber ring auxiliary mechanical sealing structure is not suitable any more. Therefore, it is necessary to design a mechanical seal structure which is suitable for high temperature and high rotation speed conditions, has strong reliability and is simple in structure.
Disclosure of Invention
The invention aims to provide a mechanical sealing structure for an air turbine assembly of a hypersonic aircraft, which solves the problems in the prior art and can realize good sealing effect under the conditions of high ambient temperature and high rotating speed.
In order to achieve the purpose, the invention provides the following scheme:
the invention provides a mechanical sealing structure for an air turbine component of a hypersonic aircraft, which comprises a sealing shell, a metal corrugated pipe, a first corrugated pipe support, a second corrugated pipe support, a clamping base, a friction static ring, a friction dynamic ring, a flexible graphite packing, a flexible graphite gasket, a baffle plate and a metal base, wherein the metal corrugated pipe is arranged on the sealing shell;
the sealing shell is sleeved outside the turbine shaft, a turbine disc is arranged on the turbine shaft at the tail end of the sealing shell, turbine movable blades are arranged outside the turbine disc, and turbine guide vanes are arranged at the head ends of the turbine movable blades; the interior of the sealing shell is a sealing cavity, the connecting part of the clamping base is connected to the tail end of the sealing shell, the mounting part of the clamping base is positioned in the sealing cavity, the inner ring head end of the mounting part of the clamping base is fixedly connected with the first corrugated pipe support, the inner ring tail end of the mounting part of the clamping base is provided with an axial groove, the second corrugated pipe support is provided with a convex tooth matched with the groove, the second corrugated pipe support is connected with the axial groove on the mounting part of the clamping base through the convex tooth, and the metal corrugated pipe is connected between the first corrugated pipe support and the second corrugated pipe support; a friction static ring for circumferential limiting is arranged at the tail end of the second corrugated pipe support, a friction moving ring is arranged between the friction static ring and the turbine disc, the friction moving ring is embedded in the metal base, the metal base is in interference fit with the turbine shaft, a flexible graphite packing is arranged between an inner ring of the metal base and the turbine shaft, and a flexible graphite gasket is arranged between the tail end face of the metal base and the turbine disc; a bearing is arranged between the head end of the sealed cavity and the turbine shaft, and a sleeve is sleeved on the turbine shaft between the bearing and the metal base;
the bearing is characterized in that a baffle plate is arranged in the sealing cavity, an oil conveying hole is formed in the head end of the sealing shell, and cooling oil conveyed by the oil conveying hole flows into the inner cavity of the metal corrugated pipe after being guided by the baffle plate and then enters the bearing cavity of the bearing through the inner side of the baffle plate.
Preferably, the inboard connecting disc chamber baffle of the base of turbine stator vane, disc chamber baffle sets up in the disc intracavity of turbine dish, the bottom plate body orientation of disc chamber baffle the seal shell is bent.
Preferably, the connecting portion of the chucking base is connected to the rear end of the sealing case by a bolt.
Preferably, a graphite gasket is arranged between the connecting part of the clamping base and the end face of the tail end of the sealing shell.
Preferably, an axial groove is formed in the outer circumference of the static friction ring and is matched with the convex teeth on the second corrugated pipe support, the end face of the head end of the static friction ring is in contact with the second corrugated pipe support, and the end face of the tail end of the static friction ring is in dynamic friction seal with the dynamic friction ring.
Preferably, the head end of the baffle plate is connected with the sealed shell through a bolt, and the tail end of the baffle plate extends into the inner cavity of the metal corrugated pipe.
Preferably, the friction stationary ring is made of graphite, silicon carbide or hard alloy.
Preferably, the friction rotating ring is made of graphite, silicon carbide or hard alloy.
Preferably, the first bellows support is welded to the clamping base.
Preferably, the metal bellows is welded between the first bellows mount and the second bellows mount.
Compared with the prior art, the invention has the following beneficial technical effects:
according to the mechanical sealing structure for the hypersonic aircraft air turbine assembly, fuel for cooling is injected into the bearing cavity through the fuel delivery hole, flows around the baffle plate, and flow and heat exchange of the area near the corrugated pipe part are enhanced; flows into the bearing cavity along the interlayer between the turbine shaft and the baffle plate and finally flows out of the bearing cavity. The corrugated pipe is fixed by adopting a welding mode of the metal support and the corrugated pipe, so that a good sealing effect can be achieved, and the strength of the joint can be guaranteed to reach the standard. The circumferential rotation is limited by adopting a mode that the grooves are arranged on the excircle and the convex teeth are matched, and axial displacement compensation can be provided. The mode of clamping the silicon carbide rotating ring by the metal base is adopted, so that the degree of eccentric motion of the silicon carbide rotating ring is reduced. The sealing device has the characteristics of high upper limit of working temperature and rotating speed, good cooling and heat exchange effects, lower working temperature of the bearing and simple and reliable structure.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic structural view of a mechanical seal arrangement for a hypersonic aircraft air turbine assembly in accordance with the present invention;
in the figure: 1-turbine guide vane, 2-turbine movable vane, 3-turbine disc, 4-disc cavity baffle, 5-flexible graphite gasket, 6-friction movable ring, 7-flexible graphite packing, 8-friction static ring, 9-second corrugated pipe support, 10-metal corrugated pipe, 11-baffle plate, 12-first corrugated pipe support, 13-sleeve, 14-bearing, 15-clamping base, 16-graphite gasket, 17-oil conveying hole, 18-sealing shell, 19-turbine shaft and 20-metal base.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a mechanical sealing structure for an air turbine assembly of a hypersonic aircraft, which aims to solve the problems in the prior art.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
The mechanical sealing structure for the hypersonic aircraft air turbine assembly in the embodiment is shown in fig. 1 and comprises a sealing shell 18, a metal corrugated pipe 10, a first corrugated pipe support 12, a second corrugated pipe support 9, a clamping base 15, a friction static ring 8, a friction dynamic ring 6, a flexible graphite packing 7, a flexible graphite gasket 16, a baffle plate 11 and a metal base 20;
the sealing shell 18 is sleeved outside the turbine shaft 19, a turbine disc 3 is arranged on the turbine shaft 19 at the tail end of the sealing shell 18, a turbine movable blade 2 is arranged outside the turbine disc 3, and the head end of the turbine movable blade 2 is provided with a turbine guide vane 1; the inside of the sealing shell 18 is a sealing cavity, the connecting part of the clamping base 15 is connected to the tail end of the sealing shell 18 through a bolt, a graphite gasket 16 is arranged between the connecting part and the tail end face of the sealing shell 18 to realize sealing, the mounting part of the clamping base 15 is positioned in the sealing cavity, the outer ring surface of the mounting part is contacted with the cavity wall of the sealing cavity, the head end of the inner ring of the mounting part of the clamping base 15 is welded with the first corrugated pipe support 12, an axial groove is arranged on the inner ring of the tail end of the mounting part of the clamping base 15, a convex tooth matched with the groove is arranged on the second corrugated pipe support 9, and the second corrugated pipe support 9 is connected with the axial groove on;
the metal corrugated pipe 10 is welded between the first corrugated pipe support 12 and the second corrugated pipe support 9; a friction static ring 8 for circumferential limiting is arranged at the tail end of the second corrugated pipe support 9, a friction moving ring 6 is arranged between the friction static ring 8 and the turbine disc 3, the friction moving ring 6 is embedded in a metal base 20, the metal base 20 is in interference fit with a turbine shaft 19, a flexible graphite packing 7 is arranged between the inner ring of the metal base 20 and the turbine shaft 19, and the flexible graphite packing 7 is tightly pressed in the center of the metal base 20 to prevent the leakage of shaft gap lubricating oil; and a flexible graphite gasket 5 is arranged between the end surface of the tail end of the metal base 20 and the turbine disc 3. The second corrugated pipe support 9 realizes circumferential limiting of the second corrugated pipe support 9 through arrangement of the convex teeth and the axial grooves on the mounting part of the clamping base 15, further limits circumferential rotation of the metal corrugated pipe 10, bears torque brought by friction between a dynamic friction ring and a static friction ring, and meanwhile, the second corrugated pipe support 9 can perform axial displacement compensation along the grooves; under the operation condition, the metal corrugated pipe 10 is in a compressed state, and the right thrust acts on the second corrugated pipe support 9 rightwards and is further transmitted to the friction static ring 8.
A bearing 14 is arranged between the head end of the sealed cavity and a turbine shaft 19, and a sleeve 13 is sleeved on the turbine shaft 19 between the bearing 14 and a metal base 20.
The sealing cavity is internally provided with a baffle plate 11, the head end of the sealing shell 18 is provided with an oil conveying hole 17, cooling oil conveyed by the oil conveying hole 17 flows into the inner cavity of the metal corrugated pipe 10 after being guided by the baffle plate 11, and then enters the bearing cavity of the bearing 14 through the inner side of the baffle plate 11 to play a role in cooling and lubricating the bearing 14. The baffle plate 11 is used for guiding lubricating oil to rush into a narrow cavity between the mechanical seal and the shaft so as to enhance the flow and heat exchange of cooling oil at the position and prevent fuel oil coking caused by flow dead zones.
In the present embodiment, an axial groove is disposed on the outer circumference of the static friction ring 8, and is matched with a convex tooth on the second bellows support 9, so as to limit the circumferential rotation of the static friction ring 8; the end surface of the head end of the static friction ring 8 is in contact with the second corrugated pipe support 9, and the end surface of the tail end of the static friction ring 8 is in dynamic friction seal with the dynamic friction ring 6.
In the embodiment, the inner side of the base of the turbine guide vane 1 is connected with a disc cavity baffle 4, the disc cavity baffle 4 is arranged in the disc cavity of the turbine disc 3, and a bottom plate body of the disc cavity baffle 4 is bent towards the sealing shell 18; the disc cavity baffle 4 plays a role in blocking hot gas leakage from a static clearance in the cavity of the turbine disc 3, so that the effects of heat insulation and sealing structure protection can be achieved, and the phenomenon that the rotary airflow forms a large vortex in a large space of the disc cavity to cause vibration can be prevented.
In this embodiment, the head end of the baffle plate 11 is connected to the sealed housing 18 by bolts, and the tail end of the baffle plate 11 extends into the inner cavity of the metal corrugated pipe 10.
In this embodiment, the friction stationary ring 8 is made of graphite, silicon carbide or hard alloy; the friction ring 6 is made of graphite or silicon carbide or hard alloy, and the inner ring is made of a metal base 20 clamping wear-resistant material and provides good axial rigidity to prevent axial movement.
In this embodiment, the friction dynamic ring and the static ring may be made of graphite-silicon carbide, graphite-cemented carbide, cemented carbide-cemented carbide, and the materials of the dynamic ring and the static ring may be interchanged. In this embodiment, a combination of a graphite stationary ring and a silicon carbide rotating ring is preferred.
Note that, the direction indicated by the small arrow in fig. 1 is the flow direction of the cooling oil; the direction indicated by the large arrow is the flowing direction of the main flow gas working medium.
The principle and the implementation mode of the invention are explained by applying specific examples, and the description of the above examples is only used for helping understanding the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In summary, this summary should not be construed to limit the present invention.