High-temperature-rise combustion chamber applied to small supersonic turbine engine

Abstract

The high-temperature-rise combustion chamber comprises a sudden expansion diffuser, a cartridge receiver, a combined air atomizing nozzle and a flame tube and can solve the problems that in the prior art, a high-temperature-rise combustion chamber of a small and medium-sized turbojet engine is low in fuel oil supply pressure and fuel oil flow is increased, so that fuel oil atomization is poor, the combustion efficiency is low, and the combustion efficiency is low. And the service life of the flame tube is difficult to meet the requirement due to great reduction of the cooling air quantity and increase of the cooling air temperature. An overall layout form of fuel oil radial grading and axial grading is innovatively adopted, and swirlers used for assisting fuel oil atomization all adopt a beveling hole mode; space compound angles are innovatively adopted for cooling holes in the flame tube, and the overall layout form of different sizes and different hole pitches is adopted in different areas. Fuel oil atomization quality and efficient combustion under various working conditions can be improved, the service life of the flame tube is prolonged, and meanwhile the machining process of the swirler is simplified due to the fact that the swirler adopts an inclined hole mode.

Description

Technical Field

[0001] The invention relates to the technical field of small turbine engine combustion chambers for hypersonic unmanned aerial vehicles, and in particular to a high temperature rise combustion chamber applied to a small supersonic turbine engine. Background Art

[0002] As the oil-gas ratio of a high-temperature rise combustion chamber increases, the fuel flow rate supplied to the combustion chamber gradually increases. In order to fully atomize more fuel and burn it efficiently, researchers will use staged supply of fuel and adopt corresponding fuel atomization methods to achieve fuel atomization. The resulting fuel center-staged combustion chamber, radial-staged combustion chamber or axial-staged combustion chamber, by comparison, radial-staged and circumferential-staged combustion chambers have larger radial and axial requirements for the combustion chamber, respectively, and are more suitable for large engines; more researchers will use a center-staged combustion chamber, because the fuel flow rate increases and the amount of air assisting fuel atomization gradually increases, forming a head atomization device with a combination of multiple oil circuits + multi-stage swirlers, which has larger requirements for the radial dimensions of the combustion chamber, making it difficult to apply to small-sized high-temperature rise combustion chambers. And most of the swirlers in this configuration use blade-type swirlers, and only a small number of swirlers have circular holes in the first-stage swirler, which makes the multi-stage swirler structure too complicated.

[0003] While the oil-gas ratio of the high-temperature rise combustion chamber is increased, the inlet temperature of the combustion chamber is further increased, but the amount of gas used for cooling the high-temperature rise combustion chamber is greatly reduced. Compared with the cooling air volume of the conventional combustion chamber, the cooling air volume of the high-temperature rise combustion chamber is reduced by nearly 40%, which increases the heat load on the flame tube wall. Researchers will adopt various advanced cooling methods (such as divergent cooling, impingement + divergent cooling) to improve the heat exchange efficiency of the cooling air, reduce the flame tube wall temperature and temperature gradient, and increase the service life of the flame tube. Summary of the invention

[0004] The object of the present invention is to provide a high temperature rise combustion chamber for a small supersonic turbine engine in order to solve the above problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] The present invention provides a high temperature rise combustion chamber for a small supersonic turbine engine, comprising a sudden expansion diffuser, a casing, a combined air atomizing nozzle, and a flame tube, wherein the right end of the sudden expansion diffuser is connected to the left end of the casing, the combined air atomizing nozzle and the flame tube are located inside the casing, and the combined air atomizing nozzle partially extends into the flame tube.

[0007] As a preferred embodiment of the present invention, the combined air atomizing nozzle includes a centrifugal nozzle, a main oil circuit, a direct-injection nozzle, a primary swirler and a secondary swirler. The centrifugal nozzle, the primary swirler, the main oil circuit and the secondary swirler are sequentially combined and connected as one body. The direct-injection nozzle penetrates the casing shell and penetrates into the flame tube. There are three air paths in the primary swirler and the secondary swirler. The first air path is composed of 4-8 first air holes with circular cross-sections. The second air path is composed of 6-10 second air holes with circular cross-sections. The third air path is composed of 8-20 third air holes with circular cross-sections.

[0008] As a preferred embodiment of the present invention, the main oil circuit includes an oil inlet, an oil tank, an oil injection hole, and an oil channel. The fuel enters the oil tank through the oil inlet and is rotated and injected into the oil channel through four oil injection holes.

[0009] As a preferred embodiment of the present invention, the vents of the three air paths have their own spatial angles; and the circumferential deflection angles of the vents of the first air path and the vents of the second air path are opposite; and the apertures of all the vents are between 4mm and 7mm.

[0010] As a preferred embodiment of the present invention, the flame tube includes a flame tube wall, a main combustion hole, and a cooling hole. The main combustion hole and the cooling hole are arranged on the flame tube wall, and the cooling hole is arranged in the front and rear areas of the main combustion hole.

[0011] As a preferred embodiment of the present invention, the third oil circuit extending into the interior of the combustion chamber adopts a direct-injection nozzle structure, and its end face is provided with two oil injection holes, and the direct-injection nozzle penetrates into the main combustion hole of the flame tube; in order to better realize the atomization of the fuel, the main combustion hole adopts a flanged hole structure.

[0012] As a preferred embodiment of the present invention, the flange height of the flange hole of the main combustion hole is between 0-4mm, and the nozzle insertion depth is 2mm-5mm.

[0013] As a preferred embodiment of the present invention, the number of main combustion holes is 1 or 2 times the number of direct-injection nozzles.

[0014] As a preferred embodiment of the present invention, the cooling holes on the flame tube wall in the high temperature zone before and after the main combustion hole are spatial compound angles, with radial (25°-35°) and circumferential (20°-40°) angles, and the hole diameter is between 0.3mm-0.5mm.

[0015] The beneficial effects of the present invention are:

[0016] (1) The high temperature rise combustion chamber of the present invention adopts a combined overall layout of radial fuel grading + axial fuel grading to achieve wide range regulation of fuel flow. Compared with traditional radial grading combustion chambers and axial grading combustion chambers, it has lower requirements on the size of the combustion chamber and is more suitable for use in small-sized high temperature rise combustion chambers.

[0017] (2) In the combined air atomizing nozzle of the high temperature rise combustion chamber of the present invention, the air swirl that assists the fuel atomization and the swirl that constructs the head recirculation zone are both constructed through air vents with circular cross-sections. Compared with the blade-type swirler, it has a simple structure and a simpler process.

[0018] (3) The axial grading scheme of the high temperature rise combustion chamber of the present invention realizes fuel atomization and mixing with air through the main combustion hole jet, avoiding excessive oil-gas ratio in the head to cause oil-rich combustion and uneven combustion, which is conducive to achieving efficient combustion and reducing pollutants.

[0019] (4) In the present invention, the flame tube wall of the high temperature rise combustion chamber adopts composite divergent cooling holes, and the cooling hole sizes and spatial angles are different according to different positions, which is more conducive to reducing the flame tube wall temperature and temperature gradient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a general schematic diagram of a high temperature rise combustion chamber of the present invention;

[0021] Figure 2 It is the layout diagram of the fuel nozzle of the present invention;

[0022] Figure 3 The schematic diagram of the cross-sectional structure of the combined air atomizing nozzle of the present invention is

[0023] Figure 4 It is a structural schematic diagram of the combined air atomizing nozzle of the present invention;

[0024] Figure 5 It is a schematic diagram of the flame tube cooling structure of the present invention;

[0025] Figure 6 A partial enlarged schematic diagram of the flame tube cooling structure of the present invention

[0026] Figure 7 It is a schematic diagram of three types of cooling holes of the flame tube cooling structure of the present invention.

[0027] Figure markings: 1-sudden expansion diffuser, 2-casing, 3-combined air atomizing nozzle, 31-centrifugal nozzle, 32-main oil circuit, 321-oil inlet, 322-oil tank, 323-injection hole one, 324-oil channel, 33-straight nozzle, 331-injection hole two, 34-first-stage swirler, 341-first air vent, 35-second-stage swirler, 351-second air vent, 352-third air vent, 4-flame tube, 41-flame tube wall, 42-main combustion hole, 43-cooling hole, 431-cooling hole one, 432-cooling hole two, 433-cooling hole three, a-fuel, b-air. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the implementation method of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0030] Combined with Figure 1-7 The present invention is a high temperature rise combustion chamber for a small supersonic turbine engine, such as Figure 1 As shown, it includes a sudden expansion diffuser 1, a casing 2, a combined air atomizing nozzle 3, and a flame tube 4. The right end of the sudden expansion diffuser 1 is connected to the left end of the casing 2. The combined air atomizing nozzle 3 and the flame tube 4 are located inside the casing 2, and the combined air atomizing nozzle 3 partially extends into the flame tube 4.

[0031] like Figure 2-4 As shown, the combined air atomizing nozzle 3 includes a centrifugal nozzle 31, a main oil circuit 32, a direct-injection nozzle 33, a primary swirler 34 and a secondary swirler 35. The centrifugal nozzle 31, the primary swirler 34, the main oil circuit 32 and the secondary swirler 35 are sequentially combined and connected as a whole. The direct-injection nozzle 33 penetrates the outer shell of the casing 2 and penetrates into the interior of the flame tube 4. The primary swirler 34 and the secondary swirler 35 have three air passages. The first air passage is composed of 4-8 first air holes 341 with circular cross-sections; the second air passage is composed of 6-10 second air holes 351 with circular cross-sections; and the third air passage is composed of 8-20 third air holes 352 with circular cross-sections.

[0032] The main oil circuit 32 includes an oil inlet 321 , an oil groove 322 , an oil injection hole 323 , and an oil passage 324 . The fuel enters the oil groove 322 through the oil inlet 321 , and is rotated and injected into the oil passage 324 through the four oil injection holes 323 .

[0033] The combined air atomizing nozzle 3 adopts a combined overall layout of radial fuel classification + axial fuel classification, that is, the fuel is divided into three routes (the internal fuel route of the combustion chamber, and the external fuel route of the combustion chamber is not introduced for the time being) to supply the combustion chamber flame tube 4; the radial fuel classification is divided into two fuel flow paths, of which the central fuel path adopts a centrifugal nozzle 31, and the main fuel path 32 adopts a pre-film air atomizing nozzle method; there is only one axial fuel classification, which adopts a direct injection nozzle 33. The two radial fuel paths are integrated with the primary swirler 34 and the secondary swirler 35 to form the combined air atomizing nozzle 3. The first fuel a is sprayed into the flame tube 4 through the centrifugal nozzle 31 at the center of the combined air atomizing nozzle 3; the fuel nozzle 31 can be fixed on the combustion chamber casing 2; the second fuel a enters the oil groove 322 through the oil inlet hole 321, and is rotated and sprayed into the oil channel 324 through four injection holes 323 with a certain spatial angle, flows along the oil channel 324 and forms an oil film a at the end of the oil channel 324, and flows into the flame tube 4 with the air b; this part of the fuel is coaxially distributed with the centrifugal nozzle and is located on the outside of the central fuel; the main oil circuit 32 can be designed integrally with the central centrifugal nozzle 31, or it can be connected to the fuel main pipe to be supplied by the external oil circuit of the combustion chamber. The axially graded third fuel a is sprayed out through the second fuel injection hole 331 on the direct-injection nozzle 33, broken up by the jet air b of the main combustion hole 42 of the flame tube, and mixed with it to enter the flame tube 4; the direct-injection nozzle 33 is fixed on the casing 2 and connected to the external oil circuit, and can also be considered to be integrated with other oil circuits; the number of main combustion holes 42 is 1 or 2 times the number of direct-injection nozzles 33 to ensure uniform distribution of the fuel.

[0034] like Figure 4 As shown, part of the air b at the outlet of the sudden expansion diffuser 1 passes through the first air vent 341 of the first-stage swirler 34 and rotates into the flame tube 4; part of the air b passes through the second air vent 351 of the second-stage swirler 35 and rotates into the flame tube 4; at the end of the oil channel 324, the two air flows b interact with each other, helping the oil film a to break into oil droplets, forming an oil-gas mixture that flows downstream and is mixed with the air b that passes through the third air vent 352, and enters the flame tube 4 to burn.

[0035] like Figure 5-7As shown, the flame tube 4 includes a flame tube wall 41, a main combustion hole 42, and a cooling hole 43. The main combustion hole 42 and the cooling hole 43 are arranged on the flame tube wall 41, and the cooling hole 43 is arranged in the front and rear areas of the main combustion hole 42. A plurality of exhaust gas cooling holes 43 are arranged near the front and rear areas of the main combustion hole 42. The aperture of the cooling hole 43 is 0.3mm-0.5mm. Three types of cooling holes 43 are simply cited, namely cooling hole 1 431, cooling hole 2 432, and cooling hole 3 433. The circumferential angle between cooling hole 1 431 and the flame tube wall 41 is 0°, the circumferential angle between cooling hole 2 432 and the flame tube wall 41 is 30°, and the circumferential angle between cooling hole 3 433 and the flame tube wall 41 is 21°. Such a structural design can improve the heat exchange efficiency of the cooling gas, and even if the gas volume is reduced, the temperature distribution and temperature gradient of the flame tube wall can be guaranteed.

[0036] Working principle:

[0037] When the small supersonic turbine engine transitions from ignition start to slow running condition, the engine fuel supply system only supplies fuel to the centrifugal nozzle 31 oil circuit of the high temperature rise combustion chamber, and the flow rate of fuel a gradually increases; at the same time, the flow rate of air b entering the combustion chamber also gradually increases, and a small amount of air b will generate swirl through the first air vent 341 on the first-stage swirler 34. The swirling air b can play a secondary role in breaking up the initially atomized fuel a, so that the fuel a is well atomized, stable combustion can be achieved, and it is not easy to flameout.

[0038] When a small supersonic turbine engine transitions from slow-running operation to cruising operation (medium operation), the engine fuel supply system starts to supply fuel to the main oil circuit 32. As the intake volume of the engine air b increases, the flow rate of the fuel a in this circuit gradually increases. The fuel a passes through the oil inlet hole 321 of the main oil circuit 32, the oil groove 322, and the oil injection hole 1 323, and forms an oil film at the end of the oil channel 324; the air b enters the three air passages of the swirlers 34 and 35, and forms two swirling air b with opposite options and different flow rates at the end of the oil channel 324. The oil film is unstable and atomized under the action of the primary swirling air 34 and the secondary swirler 35 air b, that is, the pre-film air atomizing nozzle starts to work. This part of the atomized fuel a is distributed in the coaxial outer area of ​​the centrifugal nozzle 31 fuel a, and the fuel a is evenly distributed radially, which can achieve efficient combustion in the high-temperature rise combustion chamber.

[0039] When the small supersonic turbine engine transitions from the cruise condition to the design point condition (high condition), the engine fuel supply system starts to supply the third fuel. As the engine intake volume b increases, the flow rate of the fuel a gradually increases. This part of the fuel a uses the impact of the high-speed air b jet passing through the main combustion hole 42 of the flame tube 4 to achieve rapid deformation, oil film breakage and atomization of the fuel a jet, and then mixes with the air b jet of the main combustion hole 42 and enters the flame tube 4 for combustion, that is, the direct injection nozzle 33 starts to work. Part of this part of the fuel a enters the reflow zone of the main combustion zone, and part of it burns after the main combustion hole. The main combustion zone will not be over-rich in fuel a, and the fuel is distributed along the axial direction and burned efficiently.

[0040] In the high-temperature area before and after the main combustion hole 42, the cooling holes 43 on the flame tube wall 41 are spatial compound angles, with axial and circumferential angles. Such cooling holes 43 increase the heat exchange area with the flame tube wall 41, which is beneficial to reducing the temperature of the flame tube wall 41; such cooling holes 43 have a circumferential deflection angle, which matches the swirling air b inside the flame tube 4, and better reduces the wall 41 temperature and temperature gradient.

[0041] Such a small-sized high-temperature rise combustion chamber fuel combined atomization device has a simpler structure, higher reliability, and greater versatility, and is more suitable for small turbine engines in a wide airspace and speed range.

[0042] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, the above embodiments are only preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and embodiments, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A high temperature rise combustion chamber for a small supersonic turbine engine, characterized in that: The invention comprises a sudden expansion diffuser (1), a casing (2), a combined air atomizing nozzle (3), and a flame tube (4). The right end of the sudden expansion diffuser (1) is connected to the left end of the casing (2). The combined air atomizing nozzle (3) and the flame tube (4) are located inside the casing (2), and the combined air atomizing nozzle (3) partially extends into the flame tube (4).

2. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 1, characterized in that: The combined air atomizing nozzle (3) comprises a centrifugal nozzle (31), a main oil circuit (32), a direct-injection nozzle (33), a primary swirler (34) and a secondary swirler (35). The centrifugal nozzle (31), the primary swirler (34), the main oil circuit (32) and the secondary swirler (35) are sequentially combined and connected to form an integral body. The direct-injection nozzle (33) penetrates the casing (2) shell and penetrates into the flame tube (4). The primary swirler (34) and the secondary swirler (35) have three air passages. The first air passage is composed of 4 to 8 first air vents (341) with circular cross sections. The second air passage is composed of 6 to 10 second air vents (351) with circular cross sections. The third air passage is composed of 8 to 20 third air vents (352) with circular cross sections.

3. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 1 or 2, characterized in that: The combined air atomizing nozzle (3) adopts a combined overall layout of radial fuel classification + axial fuel classification; the radial fuel classification is divided into two fuel flow paths, wherein the central fuel path adopts a centrifugal nozzle (31) and the main fuel path (32) adopts a pre-filmed air atomizing nozzle method; there is only one axial fuel classification path, which adopts a direct injection nozzle (33) method.

4. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 3, characterized in that: The vent holes of the three air passages all have their own spatial angles; the vent holes (341) of the first air passage and the vent holes (351) of the second air passage have opposite circumferential deflection angles, and the apertures of all vent holes are between 4 mm and 7 mm.

5. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 4, characterized in that: The main oil circuit (32) includes an oil inlet (321), an oil groove (322), an oil injection hole (323), and an oil passage (324). The fuel enters the oil groove (322) through the oil inlet hole (321) and is rotated and injected into the oil passage (324) through the four oil injection holes (323).

6. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 5, characterized in that: The flame tube (4) comprises a flame tube wall surface (41), a main combustion hole (42), and a cooling hole (43); the main combustion hole (42) and the cooling hole (43) are arranged on the flame tube wall surface (41).

7. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 6, characterized in that: The third oil passage extending into the combustion chamber adopts a direct-injection nozzle (33) structure, and a second oil injection hole (331) is arranged on its end surface. The direct-injection nozzle (33) penetrates into the main combustion hole (42) on the outer ring of the flame tube (4). The main combustion hole (42) adopts a flanged hole structure; the flange height of the flanged hole is between 0-4 mm, and the insertion depth of the direct-injection nozzle (33) is 2 mm-5 mm.

8. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 7, characterized in that: The number of the main combustion holes (42) is 1 or 2 times the number of the direct-injection nozzles (33).

9. A high temperature rise combustion chamber for a small supersonic turbine engine according to claim 8, characterized in that: The cooling holes (43) generally adopt a composite divergent form, and the diameters and spatial angles of the cooling holes (43) at different positions are different; wherein, in the high temperature zone before and after the main combustion hole (42), the diameter of the cooling holes (43) is between 0.3 mm and 0.5 mm, the radial angle between the cooling holes (43) and the flame tube wall (41) is between 25° and 35°, and the circumferential angle is between 20° and 40°.

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