Turbojet engine of dynamic pressure air bearing

Abstract

The invention belongs to the technical field of turbojet engines, and particularly relates to a turbojet engine of a dynamic pressure air bearing. The air bearing forwards penetrates through a front thrust plate and backwards penetrates through a rear thrust plate and an inner pipe shaft, and the two ends of the air bearing are connected with a centrifugal compressor impeller and a turbine respectively; the H-shaped dynamic pressure air bearing and the assembly thereof are located between the rectifying plate and the combustion chamber, and the combustion chamber is arranged between the inner pipe shaft and the front shell cylinder and between the inner pipe shaft and the rear shell cylinder. The turbine and the centrifugal compressor impeller are concentrically installed on the air bearing, the nozzle ring is located in front of the turbine, and the exhaust nozzle is located behind the turbine. According to the invention, by adopting the H-shaped dynamic pressure air bearing and the assembly thereof, a gas film formed during rotation of the bearing is utilized to support and lubricate a rotating part, so that frictional wear is greatly reduced, and the problems that the service life is short and the bearing needs to be frequently replaced due to high-speed rotation and quick wear of the bearing of a traditional turbojet engine are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of turbojet engines, and particularly relates to a turbojet engine with dynamic pressure air bearing. BACKGROUND

[0002] With the rapid development of science and technology, micro turbojet engines have shown great application potential and market value in the fields of aviation, aerospace, national defense and civil use due to their small size, light weight, high energy density and large thrust-to-weight ratio. Its high efficiency, energy saving and environmental protection, high reliability, easy maintenance, superior starting performance and cost-effectiveness make it an important direction for the development of related technologies.

[0003] However, there are still many problems to be solved in the practical application of traditional micro turbojet engines. Among them, the performance of the bearing system is the key factor restricting its development: the traditional bearing has a fast wear rate due to the need to withstand the severe friction caused by the high-speed rotation of the engine, resulting in a generally short service life of the engine, usually only 50 hours. Frequent replacement of bearings not only greatly increases the maintenance cost, but also seriously affects the continuous working ability and reliability of the engine. In addition, in order to ensure high performance operation, traditional turbojet engines often consume a large amount of fuel, which not only increases the use cost, but also increases the environmental pressure, which is contrary to the current development trend of high efficiency, energy saving, environmental protection and emission reduction.

[0004] The emergence of dynamic pressure air bearing technology provides a new way to solve the above problems. Dynamic pressure air bearing uses the gas generated during the operation of the engine as a lubricant, without the need for additional lubricating medium, which not only reduces the complexity and additional energy consumption of the system, but also effectively reduces the friction between the bearing and the shaft sleeve through the formation of a gas film, significantly prolonging the service life of the bearing and reducing the frequency of bearing replacement and maintenance costs. At the same time, through the optimization of gas flow and bearing structure design, dynamic pressure air bearing can effectively improve the fuel economy of the engine and reduce fuel consumption. In addition, it has good absorption capacity for impact load, which can further improve the overall stability and reliability of the engine.

[0005] Therefore, in view of the high energy consumption, fast wear, and insufficient stability of traditional micro turbojet engines, the development of micro turbojet engines based on dynamic pressure air bearing is an inevitable choice to meet the development trend of high efficiency, energy saving, stable performance, low maintenance cost, and environmental protection and emission reduction, and is of great significance to the progress and application expansion of micro turbojet engine technology. SUMMARY

[0006] In view of the technical problems existing in the above-mentioned traditional micro turbojet engine, the present application provides a turbojet engine with dynamic pressure air bearing, which changes the lubrication mode of the bearing to overcome the defects of high energy consumption, fast wear and instability of the turbojet engine.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is: A turbojet engine with dynamic pressure air bearing, comprising a starting motor, an air inlet pressure shell, an air diffuser, a front shell cylinder, a rear shell cylinder, a centrifugal compressor impeller, an H-shaped dynamic pressure air bearing and its assembly, an inner tube shaft, a combustion chamber, a turbine, a nozzle ring, a tail nozzle and a fairwater; the air bearing passes through the front thrust plate forwardly and the rear thrust plate and the inner tube shaft rearwardly, and the two ends thereof are connected with the centrifugal compressor impeller and the turbine respectively; the H-shaped dynamic pressure air bearing and its assembly are located between the fairwater and the combustion chamber, the combustion chamber is arranged between the inner tube shaft and the front shell cylinder and the rear shell cylinder; the centrifugal compressor impeller compresses the air entering through the air inlet pressure shell and sends it into the combustion chamber, the turbine is concentrically installed on the air bearing with the centrifugal compressor impeller, the nozzle ring is located in front of the turbine, and the tail nozzle is located behind the turbine.

[0008] It also comprises a connecting shaft sleeve, an oil delivery pipe, an air pipe and a bearing fixing bolt; the starting motor is connected with the air bearing through the connecting shaft sleeve to drive the air bearing to rotate; the air diffuser is located behind the air inlet pressure shell, and its output end is connected with the fairwater to diffuse the air entering through the air inlet pressure shell; one end of the oil delivery pipe is connected with an external oil supply device, and the other end thereof is connected into the combustion chamber to deliver fuel oil; one end of the air pipe is communicated with an external air source, and the other end thereof is connected into the combustion chamber to assist air supply.

[0009] The H-shaped dynamic pressure air bearing and its assembly comprise an H-shaped sleeve front end cover, an L-shaped sleeve, an H-shaped sleeve, a rear thrust plate, a front thrust plate, an H-shaped sleeve shell, an air bearing and an H-shaped sleeve rear end cover; the bearing fixing bolt passes through sleeve screw holes on the H-shaped sleeve shell to fixedly connect the H-shaped sleeve and the H-shaped sleeve shell and arrange them tangentially.

[0010] When in dynamic balance, the axis of the air bearing coincides with the axes of the front thrust plate, the rear thrust plate, the H-shaped sleeve, the H-shaped sleeve shell, the front shell cylinder, the rear shell cylinder and the inner tube shaft; the front end of the H-shaped sleeve shell is connected with the inner edge of the H-shaped sleeve front end cover, and the H-shaped sleeve front end cover is connected with the fairwater.

[0011] The H-shaped sleeve front end cover is provided with a front end cover lateral screw hole and a front end cover forward screw hole, the front end cover lateral screw hole is connected with the fairwater through a bolt, and the front end cover forward screw hole is connected with the H-shaped sleeve through a bolt.

[0012] The front thrust plate is fixed in the inner side of the front shell cylinder through the L-shaped sleeve, the front thrust plate is engraved with radially spiral grooves which are annularly distributed outwardly with the axis as the center, and the depth of the radially spiral grooves is 5 μm; the rear thrust plate is interference-fitted with the air bearing, and the rear thrust plate is engraved with spiral grooves which are annularly distributed outwardly with the axis as the center.

[0013] The air bearing is provided with axial spiral grooves and screw grooves which are symmetrically distributed in a ring shape outwardly from the central axis.

[0014] The H-shaped sleeve is provided with a plurality of rows of air inlet holes and air chambers, the air inlet holes are distributed in the middle section of the H-shaped sleeve, and each row of air inlet holes is distributed in a ring shape with the inner tube shaft axis as the center line; after the gas enters the air chamber through the air inlet hole and converges, the air film is formed in the gap between the air bearing and the H-shaped sleeve.

[0015] Compared with the prior art, the present application has the beneficial effects that: By adopting the H-shaped dynamic pressure air bearing and its assembly, the gas film formed during the rotation of the bearing is used to support and lubricate the rotating part, greatly reducing the friction and wear, effectively overcoming the problem of short service life and frequent bearing replacement caused by the fast wear of the bearing during high-speed rotation of the traditional turbojet engine, significantly prolonging the service life of the engine and reducing the maintenance cost; at the same time, the additional supporting force generated by the gas film enhances the bearing carrying capacity, improves the stability and reliability of the engine operation, and does not need additional lubricant, but can realize lubrication by using the gas of the engine itself, reducing energy consumption and system complexity, and combining with the optimized gas flow design to reduce fuel consumption, conforming to the development trend of high efficiency, energy saving, environmental protection and emission reduction, making the micro turbojet engine have more advantages in the application of aviation, aerospace and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only exemplary, and those skilled in the art can also obtain other implementation drawings according to the provided drawings without creating any creative labor.

[0017] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not define the limiting conditions for the implementation of the present application, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0018] Figure 1 is a cross-sectional schematic view of the present application; Figure 2 is a structural schematic view of the H-shaped sleeve assembly of the present application; Figure 3It is the front and rear thrust plate structure schematic diagram of the present application; Figure 4 It is the front and rear thrust plate structure schematic diagram of the present application; Figure 5 It is the air bearing no-load concentric schematic diagram of the present application; Figure 6 It is the air bearing load operation schematic diagram of the present application; Figure 7 It is the bearing structure schematic diagram of the present application; Figure 8 It is the H type sleeve section schematic diagram of the present application.

[0019] Wherein: 1 is the starting motor, 2 is the connecting shaft sleeve, 3 is the front shell cylinder, 4 is the centrifugal compressor impeller, 5 is the H type sleeve front end cover, 5a1 is the front end cover lateral screw hole, 5a2 is the front end cover positive screw hole, 6 is the L type sleeve, 7 is the H type sleeve, 7a1 is the air inlet hole, 7a2 is the air chamber, 8 is the rear thrust plate, 9 is the combustion chamber, 10 is the oil pipe, 11 is the air pipe, 12 is the bearing fixing bolt, 13 is the tail nozzle, 14 is the air inlet pressure shell, 15 is the diffuser, 16 is the rectifier plate, 17 is the front thrust plate, 17a is the radial spiral groove, 18 is the H type sleeve shell, 18a is the sleeve screw hole, 19 is the air bearing, 19a is the axial spiral groove, 19b is the screw groove, 20 is the H type sleeve rear end cover, 21 is the inner tube shaft, 22 is the rear shell cylinder, 23 is the turbine, 24 is the nozzle ring. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. These descriptions are only for further illustrating the features and advantages of the present application, but not for limiting the claims of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0021] The specific embodiments of the present application will be described in further detail below in combination with the drawings and embodiments. The following embodiments are used to illustrate the present application, but not to limit the scope of the present application.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0023] This embodiment provides a turbojet engine with a dynamic pressure air bearing, such as Figure 1 As shown, the system includes a starter motor 1, an intake plenum 14, a diffuser 15, a front outer casing 3, a rear outer casing 22, a centrifugal compressor impeller 4, an H-type dynamic pressure air bearing and its components, an inner tubular shaft 21, a combustion chamber 9, a turbine 23, a nozzle ring 24, and a tail nozzle 13. The air bearing 19 extends forward through the front thrust plate 17 and rearward through the rear thrust plate 8 and the inner tubular shaft 21. The ends of the air bearing 19 connect to the centrifugal compressor impeller 4 and the turbine 23, respectively. The centrifugal compressor impeller 4 compresses the air entering through the intake plenum 14, increasing the oxygen content per unit volume, and then delivers the air to the combustion chamber 9 for combustion. The high-temperature, high-pressure combustion gas exiting the combustion chamber flows through the turbine 23, which is mounted on the same air bearing 19 as the centrifugal compressor impeller 4. A portion of the high-pressure combustion gas's internal energy expands in turbine 23 and is converted into mechanical energy, driving the rotation of centrifugal compressor impeller 4. In a jet engine with turbine 23, at equilibrium, the work performed by the gas expanding in turbine 23 equals the work consumed by centrifugal compressor impeller 4 to compress the air, plus the work required by the transmission accessories to overcome friction. After combustion, the energy of the combustion gas before turbine 23 is greatly increased, resulting in a much greater expansion ratio in turbine 23 than in centrifugal compressor impeller 4. The pressure and temperature at the turbine 23 outlet are significantly higher than at the centrifugal compressor impeller 4 inlet. The turbojet engine's thrust is derived from this portion of the combustion gas's energy.

[0024] The high-temperature, high-pressure gas flowing out of the turbine 23 continues to expand in the tail nozzle 13 and is discharged backward from the nozzle along the engine axis at a high speed. This speed is much greater than the speed of the airflow entering the engine, which enables the engine to obtain a reaction thrust.

[0025] The H-type dynamic pressure air bearing and its assembly are arranged between the fairing plate 16 and the combustion chamber 9, and the H-type dynamic pressure air bearing and its assembly include an H-type sleeve front end cover 5, an L-type sleeve 6, an H-type sleeve 7, a rear thrust plate 8, a front thrust plate 17, an H-type sleeve shell 18, an air bearing 19, and an H-type sleeve rear end cover 20. When in dynamic balance, the axis of the air bearing 19 coincides with the axes of the front thrust plate 17, the rear thrust plate 8, the H-type sleeve 7, the H-type sleeve shell 18, the front shell cylinder 3, the rear shell cylinder 22, and the inner tube shaft 21, and the H-type sleeve 7 is tangentially arranged with the H-type sleeve shell 18. The front end of the H-type sleeve shell 18 is connected with the inner edge of the front end cover 5, the front end cover 5 is connected with the fairing plate 16, and the rear end of the H-type sleeve shell 18 is connected with the inner edge of the rear end cover 20.

[0026] As shown in Figure 2 , the H-type sleeve front end cover 5 is provided with a front end cover lateral screw hole 5a1 connected with the fairing plate 16 in front, and is provided with a front end cover forward screw hole 5a2 connected with the H-type sleeve 7.

[0027] As shown in Figure 3 , 4 , a spiral groove 17a with a depth of 5 μm is engraved on the front thrust plate 17. When the air bearing 19 rotates, air continuously flows through the spiral groove 17a to provide axial bearing capacity, and the bearing capacity increases with the increase of the rotating speed.

[0028] As shown in Figure 5 , 6 , when the air bearing 19 and the H-type sleeve 7 move relatively, due to the viscosity of the gas, the gravity of the air bearing 19 itself and external force form a wedge-shaped gap between the air bearing 19 and the H-type sleeve 7. When the gas moves relatively, it moves from a large gap to a small gap, so that the gas is subjected to pressure and generates pressure, thereby generating bearing capacity. As shown in Figure 7 , the air bearing 19 is provided with symmetrical spiral grooves with a depth of 5 μm. As shown in Figure 8 , the H-type sleeve 7 has a plurality of annularly distributed air inlet holes, which are divided into two parts, the top part is an air hole 7a1, and the bottom part is an air chamber 7a2. The gas enters the air hole 7a1 from the outside, converges in the air chamber 7a2, and finally forms a gas film in the gap between the air bearing and the H-type sleeve.

[0029] The above only describes the preferred embodiments of the present application in detail, but the present application is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge possessed by those skilled in the art without departing from the purpose of the present application, and all the changes shall be included in the protection scope of the present application.

Claims

1. A turbojet engine with a dynamic pressure air bearing, characterized in that: It comprises a starter motor (1), an intake pressure casing (14), a diffuser (15), a front outer casing (3), a rear outer casing (22), a centrifugal compressor impeller (4), an H-type dynamic pressure air bearing and its components, an inner tube shaft (21), a combustion chamber (9), a turbine (23), a nozzle ring (24), a tail nozzle (13), and a rectifier plate (16); the air bearing (19) passes through the front thrust plate (17) forward and passes through the rear thrust plate (8) and the inner tube shaft (21) backward, and its two ends are respectively connected to the centrifugal compressor impeller (4) and the turbine (23); The H-type dynamic pressure air bearing and its components are located between the rectifying plate (16) and the combustion chamber (9), and the combustion chamber (9) is arranged between the inner tube shaft (21) and the front outer shell (3) and the rear outer shell (22); the centrifugal compressor impeller (4) compresses the air entering through the air intake casing (14) and sends it into the combustion chamber (9), the turbine (23) and the centrifugal compressor impeller (4) are concentrically mounted on the air bearing (19), the nozzle ring (24) is located in front of the turbine (23), and the tail nozzle (13) is located behind the turbine (23).

2. A turbojet engine with a dynamic pressure air bearing according to claim 1, characterized in that: It also includes a connecting sleeve (2), an oil delivery pipe (10), a vent pipe (11), and a bearing fixing bolt (12); the starting motor (1) is connected to the air bearing (19) through the connecting sleeve (2) to drive the air bearing (19) to rotate; the diffuser (15) is located behind the intake pressure shell (14), and its output end is connected to the rectifier plate (16) for diffusing the air entering through the intake pressure shell (14); one end of the oil delivery pipe (10) is connected to an external oil supply device, and the other end is connected to the combustion chamber (9) to transport fuel; one end of the vent pipe (11) is connected to an external air source, and the other end is connected to the combustion chamber (9) to assist ventilation.

3. The turbojet engine with a dynamic pressure air bearing according to claim 1, characterized in that: The H-type dynamic pressure air bearing and its components include an H-type sleeve front end cover (5), an L-type sleeve (6), an H-type sleeve (7), a rear thrust plate (8), a front thrust plate (17), an H-type sleeve housing (18), an air bearing (19), and an H-type sleeve rear end cover (20); the bearing fixing bolt (12) passes through the sleeve screw hole (18a) on the H-type sleeve housing (18) to fix the H-type sleeve (7) and the H-type sleeve housing (18) in connection, and the two are arranged tangentially.

4. The turbojet engine with a dynamic pressure air bearing according to claim 3, characterized in that: When in dynamic balance, the axis of the air bearing (19) coincides with the axis of the front thrust plate (17), the rear thrust plate (8), the H-type sleeve (7), the H-type sleeve housing (18), the front outer housing (3), the rear outer housing (22), and the inner tube shaft (21); the front end of the H-type sleeve housing (18) is connected to the inner edge of the H-type sleeve front end cover (5), the H-type sleeve front end cover (5) is connected to the rectifier plate (16), and the rear end of the H-type sleeve housing (18) is connected to the inner edge of the H-type sleeve rear end cover (20).

5. The turbojet engine with a dynamic pressure air bearing according to claim 3, characterized in that: The front end cover (5) of the H-shaped sleeve is provided with a front end cover lateral screw hole (5a1) and a front end cover forward screw hole (5a2); the front end cover lateral screw hole (5a1) is connected to the rectifier plate (16) via a bolt, and the front end cover forward screw hole (5a2) is connected to the H-shaped sleeve (7) via a bolt.

6. The turbojet engine with a dynamic pressure air bearing according to claim 3, characterized in that: The front thrust plate (17) is fixed to the inner side of the front outer shell (3) through an L-shaped sleeve (6), and the front thrust plate (17) is engraved with a radial spiral groove (17a) distributed in an annular manner outward with the axis as the center, and the depth of the radial spiral groove (17a) is 5μm; the rear thrust plate (8) is interference fit with the air bearing (19), and the rear thrust plate (8) is engraved with a spiral groove distributed in an annular manner outward with the axis as the center.

7. The turbojet engine with a dynamic pressure air bearing according to claim 3, characterized in that: The air bearing (19) is provided with an axial spiral groove (19a) and a spiral groove (19b) which are symmetrical with the vertical center plane and distributed annularly outward with the axis as the center. The depth of the axial spiral groove (19a) and the spiral groove (19b) are both 5 μm.

8. The turbojet engine with a dynamic pressure air bearing according to claim 3, characterized in that: The H-shaped sleeve (7) is provided with a plurality of rows of air inlet holes (7a1) and an air chamber (7a2). The air inlet holes (7a1) are distributed in the middle section of the H-shaped sleeve (7), and each row of air inlet holes (7a1) is distributed in a ring shape with the axis of the inner tube shaft (21) as the center line. After the gas enters the air chamber (7a2) through the air inlet holes (7a1) and converges, an air film is formed in the gap between the air bearing (19) and the H-shaped sleeve (7).

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