Liquid water protection sealing device suitable for low-altitude sea-skimming aircraft

Abstract

The liquid water protection sealing device comprises a rotating shaft and a sealing bush, sealing labyrinth teeth are distributed on the rotating shaft at intervals in the axial direction, the windward side of each sealing labyrinth tooth is provided with an inwards-concave labyrinth tooth arc face, and the inner surface of the sealing bush is provided with an inwards-concave bush arc face in front of the sealing labyrinth teeth. The labyrinth arc face and the lining arc face are concentric, part of water flow entering the sealing cavities flows along the labyrinth arc face, part of the water flow entering the sealing cavities flows along the lining arc face, the two parts of water flow intersect at the front portion of the sealing gap to form a water curtain, and the water flow is prevented from entering the next-stage sealing cavity. And the water inlet end is communicated with the sealed cavity. The throttling and dissipation effects of mutual matching between the sealing labyrinth and the sealing bushing are enhanced; by arranging the drainage channel, entering water is timely and effectively drained, water entering the aircraft is reduced, and the service life of the aircraft is prolonged.

Description

Technical Field

[0001] The present invention belongs to the field of aeroengine seals, and particularly relates to a liquid water protection sealing device suitable for low-altitude sea-skimming aircraft. Background Technique

[0002] With the country's strong promotion of the development of the low-altitude economy, the application fields of unmanned aerial vehicles are becoming increasingly extensive, and the operating environment has become more complex. For aircraft flying at altitudes below 1000 meters, the main challenges faced by the sealing technology have shifted from the air environment to the water environment. In the low-altitude sea-skimming flight environment, water vapor contains a large amount of salt ions such as chlorides (Cl - ), sulfates (SO4 2- ), etc. Among them, chloride ions have strong permeability and can damage the metal oxide protective film (such as the alumina layer of aluminum alloy), causing pitting corrosion, stress corrosion cracking and intergranular corrosion. Sulfates (SO4 2- ) generated due to marine biological activities and air pollution combine with water to form sulfuric acid, thus accelerating metal corrosion; carbon dioxide dissolved in seawater acidifies the water film, promoting metal corrosion; in high-speed airflows, suspended particles enter the interior of the aircraft and collide, causing micro-cutting (similar to the sandblasting effect), damaging the protective coating, and causing significant water erosion to its surface material. Therefore, in low-altitude sea-skimming flights, liquid water and water vapor containing a large amount of impurities and acidic substances impact and erode low-altitude aircraft, becoming the main reasons affecting their flight safety and service life. In order to meet the requirements of the low-altitude economy for long endurance and low energy consumption of aircraft, it is necessary to innovate the design of the existing sealing structure to cope with the challenges of liquid water and water vapor.

[0003] Among many sealing structures, labyrinth sealing is more suitable for large-scale production due to its advantages such as low cost, high structural stability and easy maintenance, and can meet the needs of the development of the low-altitude economy. However, during the operation of the labyrinth sealing structure, due to wear between the rotor and stator components and the existence of water erosion in the sea-skimming environment, the width of the throttling gap becomes larger, and the leakage of the labyrinth sealing structure increases accordingly. Therefore, how to design a reasonable labyrinth sealing structure to achieve a large pressure difference on both sides of the seal and thus achieve the sealing effect has become an urgent problem to be solved. From domestic and foreign research, it can be seen that at present, the reduction of the leakage of labyrinth sealing mainly focuses on the optimization design of the main tooth profile parameters of the labyrinth itself. For aircraft flying at low altitudes and skimming the sea, their working environment is more severe, so the design optimization of the bushing shape parameters should not be ignored.

[0004] For an aircraft flying at low altitudes and skimming the sea, liquid water and water vapor enter the interior of the sealing device through the sealing gap and produce reciprocating rebound and splashing phenomena under the action of impact kinetic energy and centrifugal force. The principle is as Figure 1As shown, the water erosion phenomenon is further aggravated under the kinetic energy addition, and the research on how to eliminate the water droplet rebound and splash is imminent; under the protection of the traditional labyrinth seal device, the liquid water entering the inside of the seal device accumulates in the seal cavity, which only plays a role in slowing down the entry of liquid water into the next-level device, so there is a lack of further treatment measures. Therefore, the improvement of the sealing technology and the reduction of the leakage amount have become one of the important measures to improve the performance and working life of low-altitude sea-skimming aircraft. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a liquid water protection seal device suitable for low-altitude sea-skimming aircraft aiming at the above-mentioned existing deficiencies. The liquid water protection seal device of the present invention can effectively slow down the entry of external water into the seal structure of the low-altitude aircraft, and at the same time can timely discharge the water entering the seal structure.

[0006] To achieve the above technical purpose, the technical solution adopted by the present invention is:

[0007] A liquid water protection seal device suitable for low-altitude sea-skimming aircraft, including a rotating shaft and a seal bushing coaxially sleeved outside the rotating shaft. A plurality of seal labyrinth teeth are distributed at intervals along the axial direction on the rotating shaft. A seal gap is formed between the outer peripheral surface of the seal labyrinth teeth and the inner ring surface of the seal bushing. A seal cavity is formed between adjacent seal labyrinth teeth. The windward surface of the seal labyrinth teeth is provided with an inwardly concave labyrinth tooth arc surface. The inner surface of the seal bushing is provided with an inwardly concave bushing arc surface in front of the seal labyrinth teeth. The labyrinth tooth arc surface and the bushing arc surface are concentric. Part of the water flow entering the seal cavity flows along the labyrinth tooth arc surface, and part flows along the bushing arc surface. The two parts of the water flow converge in front of the seal gap to form a water curtain, preventing the water flow from entering the next-level seal cavity. A drainage channel is arranged inside the rotating shaft. The drainage channel is provided with a plurality of water inlet ends, and the water inlet ends are communicated with the seal cavity. The outlet end of the drainage channel is arranged outside the liquid water protection seal device, and the water flow can enter the drainage channel through the water inlet ends and be discharged through the outlet end.

[0008] To optimize the above technical solution, the specific measures taken also include:

[0009] The surface of the above-mentioned bushing arc surface is provided with a graphite coating.

[0010] The above-mentioned seal bushing is provided with a water diversion channel in front of each bushing arc surface. One seal cavity corresponds to one bushing arc surface and one water diversion channel. The front end of the water diversion channel is located at the seal gap in front of the corresponding seal cavity, and the rear end of the water diversion channel is connected to the front end of the bushing arc surface.

[0011] The latter half of the above-mentioned water diversion channel is horizontal and tangent to the front end of the bushing arc surface.

[0012] At the bottom of each seal cavity, there is an inlet end of a drainage channel. A check valve is provided at the inlet end of the drainage channel, and the check valve allows the moisture in the seal cavity to enter the drainage channel unidirectionally.

[0013] The above check valve is an elastic diaphragm. One end of the check valve is fixed on one side of the inlet end of the drainage channel, and the other end is a free end. When the check valve is not subject to external force, the check valve covers the inlet end of the drainage channel. When subject to external force, the preset elasticity of the check valve itself enables the free end of the check valve to rotate downward but not upward. When the free end of the check valve rotates downward, the inlet end of the drainage channel is opened.

[0014] The number of the above seal labyrinth teeth is four. Correspondingly, the number of seal cavities is three, and the drainage channel has three inlet ends.

[0015] The above water diversion channel is a smooth curved channel with a concave middle part. The inlet end, outlet end and elbow of the drainage channel all adopt smooth transitions.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. The present invention changes the traditional geometric shape of the seal labyrinth teeth. The windward surface of the seal labyrinth teeth and the corresponding part of the seal bushing are designed as arc-shaped groove structures, and they are concentric circle designs. The fluid flows through the arc-shaped bushing and arc-shaped labyrinth teeth and forms a water curtain at the tip of the labyrinth teeth, which greatly prevents the oncoming flow from entering the next-stage seal cavity.

[0018] 2. The present invention is provided with a small water diversion channel at the front of each arc surface of the bushing, which diverts a part of the fluid that originally flows through the seal gap, thereby reducing the flow velocity of the fluid that originally flows through the seal gap and reducing the total flow rate flowing into the next-stage seal cavity.

[0019] 3. The flow velocity in the small water diversion channel is higher than that of the external fluid, and the second half of the water diversion channel is horizontal and tangent to the front end of the arc surface of the bushing. Therefore, the outflow of the water diversion channel accelerates the fluid flowing through the arc surface of the bushing to promote the formation of a water curtain at the tip of the labyrinth teeth. The frictional resistance along the small water diversion channel is greater than that along the seal labyrinth teeth and the seal bushing, thereby further consuming the kinetic energy of the fluid, preventing the fluid from entering the next-stage seal cavity, and making it easier for the fluid to fall to the bottom of the seal cavity and then enter the drainage channel.

[0020] 4. The surface of the arc surface of the bushing is provided with a graphite coating, which can cope with the water erosion phenomenon caused by entering the sealing device during low-altitude sea-skimming flight.

[0021] 5. The present invention provides a drainage channel within the rotating shaft for discharging the fluid that enters the sealing cavity, thus filling the gap that conventional labyrinth sealing devices cannot drain water when dealing with low-altitude sea-skimming flight. A check valve is provided at the entrance of the drainage channel. This check valve can only be opened from the sealing cavity towards the inside of the drainage channel. When water droplets impact on the check valve, the check valve opens, prompting the water droplets to be quickly discharged, reducing the damage to the sealing device caused by the repeated impact and splashing of water droplets between the labyrinth teeth.

[0022] In summary, the present invention strengthens the throttling and dissipation effects of the mutual cooperation between the sealing labyrinth teeth and the sealing bushing. Through the setting of the drainage channel, the entered water is effectively discharged in a timely manner, reducing the entry of moisture into the aircraft and extending the service life of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the impact principle of water droplets between the sealing labyrinth teeth;

[0024] Figure 2 is a schematic diagram of the sealing principle of the sealing labyrinth teeth;

[0025] Figure 3 is a schematic diagram of the waterproof principle of the labyrinth sealing of the present invention;

[0026] Figure 4 is a schematic diagram of the drainage principle of the labyrinth sealing of the present invention;

[0027] Figure 5 is a schematic diagram of the position of the water diversion channel of the present invention;

[0028] Figure 6 is a schematic diagram of the labyrinth sealing structure of the present invention.

[0029] Reference numerals are: rotating shaft 1, drainage channel 11, check valve 12, sealing bushing 2, bushing arc surface 21, graphite coating 22, sealing labyrinth teeth 3, labyrinth tooth arc surface 31, sealing cavity 4, water diversion channel 5. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order to make the objectives, technical solutions and advantages of the present application clearer, the following describes and explains the present application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0031] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. In addition, it can also be understood that although the efforts made in such a development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacturing, or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood as the content disclosed in the present application being insufficient.

[0032] When the term "embodiment" is mentioned in the present application, it means that the specific features, structures, or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those of ordinary skill in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.

[0033] Unless otherwise defined, the technical terms or scientific terms involved in the present application should have the ordinary meaning understood by those with ordinary skills in the technical field to which the present application belongs. The terms "a", "an", "one", "the", and similar words involved in the present application do not indicate a limitation in quantity and can represent a singular or plural number. The terms "including", "comprising", "having", and any variations thereof involved in the present application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or units (units) is not limited to the listed steps or units, but may also include unlisted steps or units, or may further include other steps or units inherent to these processes, methods, products, or devices. The terms "connected", "coupled", and similar words involved in the present application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The term "plurality" / "several" involved in the present application refers to two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. The terms "first", "second", "third", etc. involved in the present application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0034] A liquid water protection and sealing device for a low-altitude sea-skimming aircraft according to the present invention, such as Figure 3-6As shown in the figure, it includes a rotating shaft 1. A sealing bushing 2 is coaxially sleeved outside the rotating shaft 1. A plurality of sealing labyrinth teeth 3 are arranged on the rotating shaft 1. The sealing labyrinth teeth 3 are in non-contact sealing fit with the sealing bushing 2. The left contour of the sealing labyrinth teeth 3 is arc-shaped, and its windward surface is concave, that is, the labyrinth tooth arc surface 31. An arc-shaped groove, that is, the bushing arc surface 21, is provided at the sealing bushing 2. The labyrinth tooth arc surface 31 and the bushing arc surface 21 are concentric. A graphite coating 22 is provided on the surface of the arc-shaped groove at the sealing bushing 2. A water diversion channel 5 is provided directly above the center line of the sealing labyrinth teeth 3. A drainage channel 11 is provided in the sealing cavity 4 between the teeth of the sealing labyrinth teeth 3. A check valve 12 is provided at the entrance of the drainage channel 11. The labyrinth teeth and the bushing with the above structure cooperate with each other to form a water curtain, and the water flow state is as Figure 3 shown, which greatly prevents water from flowing into the tooth cavity of the next-stage labyrinth teeth, strengthens the sealing effect of the labyrinth tooth tips, and reduces the leakage flow of the fluid; a drainage channel 11 with a check valve 12 is added between the teeth of the labyrinth teeth, so that the incoming water can be discharged in time.

[0035] Specifically, in this embodiment:

[0036] The number of the sealing labyrinth teeth 3 is four, which are the first labyrinth tooth, the second labyrinth tooth, the third labyrinth tooth and the fourth labyrinth tooth in sequence from left to right. The sealing labyrinth teeth 3 are axially arranged on the rotating shaft 1 at equal intervals. A first cavity is formed between the first labyrinth tooth and the windward surface. A first sealing cavity is formed between the first labyrinth tooth and the second labyrinth tooth. A second sealing cavity is formed between the second labyrinth tooth and the third labyrinth tooth. A third sealing cavity is formed between the third labyrinth tooth and the fourth labyrinth tooth.

[0037] The left contour of the sealing labyrinth teeth 3 is arc-shaped, and its windward surface is concave. The sealing bushing 2 is provided with an arc-shaped groove at the first cavity, and its corresponding arc curve is designed as a concentric circle; the left contour of the second labyrinth tooth is arc-shaped, and its windward surface is concave. The sealing bushing 2 is provided with an arc-shaped groove at the first sealing cavity, and its corresponding arc curve is designed as a concentric circle; the left contour of the third labyrinth tooth is arc-shaped, and its windward surface is concave. The sealing bushing 2 is provided with an arc-shaped groove at the second sealing cavity, and its corresponding arc curve is designed as a concentric circle; the left contour of the fourth labyrinth tooth is arc-shaped, and its windward surface is concave. The sealing bushing 2 is provided with an arc-shaped groove at the third sealing cavity, and its corresponding arc curve is designed as a concentric circle.

[0038] A graphite coating 22 is provided in the arc-shaped groove of the sealing bushing 2.

[0039] A first water diversion channel is provided above the center line of the first labyrinth tooth; a second water diversion channel is provided above the center line of the second labyrinth tooth; a third water diversion channel is provided above the center line of the third labyrinth tooth.

[0040] The rear half of the first water diversion channel above the center line of the first comb teeth is horizontal and tangent to the arc-shaped groove at the sleeve in the first sealing cavity; the rear half of the second water diversion channel above the center line of the second comb teeth is horizontal and tangent to the arc-shaped groove at the sleeve in the second sealing cavity; the rear half of the third water diversion channel above the center line of the third comb teeth is horizontal and tangent to the arc-shaped groove at the sleeve in the third sealing cavity.

[0041] A first water inlet end of a drainage channel 11 is provided between the first and second grate teeth, a second water inlet end of a drainage channel 11 is provided between the second and third grate teeth, and a third water inlet end of a drainage channel 11 is provided between the second and third grate teeth.

[0042] A one-way valve 12 is provided at the entrance of each water inlet.

[0043] The water inlet and elbow of the water diversion channel 5 and the drainage channel 11 all adopt smooth transition.

[0044] The windward surface of the sealing grate teeth 3 is a smooth curved surface.

[0045] The present invention changes the traditional geometric shape of the comb teeth, and links the windward surface of the comb teeth and the corresponding part of the bushing so that a water curtain is formed when the fluid flows through to block the flow from the rear; and a small water diversion channel 5 is provided to reduce the mainstream flow while strengthening the water-blocking effect of the water curtain. A graphite coating 22 is provided in the arc groove of the bushing to further deal with water erosion; a drainage channel 11 is provided between the comb teeth to discharge the fluid entering the sealing cavity, filling the gap that the conventional comb tooth sealing device cannot drain water when dealing with low-altitude sea-skimming flights; a one-way valve 12 is provided at the entrance of the drainage channel 11 to reduce the damage to the sealing device caused by water droplets hitting back and forth between the comb teeth and repeatedly splashing. Strengthen the throttling and dissipation effect of the mutual cooperation between the comb teeth and the bushing; through the setting of the drainage channel 11, the incoming water can be discharged in a timely and effective manner, reducing the entry of water into the aircraft and extending the service life of the aircraft.

[0046] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the described embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A liquid water protection sealing device suitable for low-altitude sea-skimming aircraft, comprising a rotating shaft (1) and a sealing bushing (2) coaxially sleeved on the outside of the rotating shaft (1), a plurality of sealing grate teeth (3) are distributed axially at intervals on the rotating shaft (1), a sealing gap is formed between the outer peripheral surface of the sealing grate teeth (3) and the inner annular surface of the sealing bushing (2), and a sealing cavity (4) is formed between adjacent sealing grate teeth (3), characterized in that: The windward surface of the sealing grate teeth (3) is provided with a concave grate tooth arc surface (31), and the inner surface of the sealing sleeve (2) is provided with a concave sleeve arc surface (21) in front of the sealing grate teeth (3). The grate tooth arc surface (31) and the sleeve arc surface (21) are cocentric. The water flow entering the sealing cavity (4) flows partly along the grate tooth arc surface (31) and partly along the sleeve arc surface (21). The two parts of the water flow meet in front of the sealing gap to form a water curtain, thereby preventing the water flow from entering the next-level sealing cavity (4). A drainage channel (11) is provided in the rotating shaft (1). The drainage channel (11) is provided with a plurality of water inlet ends, which are connected to the sealing cavity (4). The outlet end of the drainage channel (11) is provided outside the liquid water protection sealing device. The water flow can enter the drainage channel (11) through the water inlet end and be discharged through the outlet end.

2. A liquid water protection sealing device suitable for low altitude sea skimming aircraft according to claim 1, characterized in that: The surface of the bushing arc surface (21) is provided with a graphite coating (22).

3. The liquid water protection sealing device suitable for low altitude sea skimming aircraft according to claim 1, characterized in that: The sealing bushing (2) is provided with a water diversion channel (5) at the front of each bushing arc surface (21); a sealing cavity (4) corresponds to a bushing arc surface (21) and a water diversion channel (5); the front end of the water diversion channel (5) is located at the sealing gap at the front of the corresponding sealing cavity (4); and the rear end of the water diversion channel (5) is connected to the front end of the bushing arc surface (21).

4. The liquid water protection sealing device suitable for low altitude sea skimming aircraft according to claim 3, characterized in that: The rear half of the water diversion channel (5) is horizontal and tangent to the front end of the bushing arc surface (21).

5. The liquid water protection sealing device suitable for low altitude sea skimming aircraft according to claim 4, characterized in that: A water inlet end of a drainage channel (11) is provided at the bottom of each sealing cavity (4), and a one-way valve (12) is provided at the water inlet end of the drainage channel (11). The one-way valve (12) allows water in the sealing cavity (4) to enter the drainage channel (11) in one direction.

6. A liquid water protection sealing device suitable for low altitude sea skimming aircraft according to claim 5, characterized in that: The one-way valve (12) is an elastic diaphragm. One end of the one-way valve (12) is fixed to one side of the water inlet end of the drainage channel (11), and the other end is a free end. When the one-way valve (12) is not subjected to external force, the one-way valve (12) covers the water inlet end of the drainage channel (11). When subjected to external force, the one-way valve (12) has its own preset elasticity so that the free end of the one-way valve (12) can rotate downward but cannot rotate upward. When the free end of the one-way valve (12) rotates downward, the water inlet end of the drainage channel (11) is opened.

7. A liquid water protection sealing device suitable for low altitude sea skimming aircraft according to claim 6, characterized in that: The number of the sealing grate teeth (3) is four, and correspondingly, the number of the sealing cavities (4) is three, and the drainage channel (11) has three water inlet ends.

8. The liquid water protection sealing device suitable for low altitude sea skimming aircraft according to claim 6, characterized in that: The water diversion channel (5) is a smooth curved channel with a concave middle portion, and the water inlet end, water outlet end and bend of the drainage channel (11) all adopt smooth transitions.

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