A backflow combustion device

Abstract

The application discloses a backflow combustion device, which comprises a shell, a vortex device installed on the shell and an air atomizing nozzle installed on the vortex device. The device adopts a design of a direct jet nozzle, an internal swirler, an atomizing venturi and a nozzle shell, has a wide fuel regulation ratio range, is not sensitive to fuel pollution, can adapt to various liquid fuels, has low requirements on fuel system pressure, uniformly mixes fuel and air, has wide spatial distribution of fuel mist, has good atomizing effect in a wide working range, can effectively reduce exhaust smoke in a high-power state, and is not easy to coke and form carbon due to the simple fuel flow channel of the direct jet nozzle and the wrapping of high-speed airflow.

Description

Technical Field

[0001] This application relates to the field of aero-engine technology, and specifically to a recirculation combustion device. Background Technology

[0002] Currently, aero-engine recirculation combustion chambers primarily employ single- or dual-fuel-path centrifugal nozzles to atomize fuel. Centrifugal nozzles have complex structures, require extremely high machining precision, are expensive, and suffer from low fuel regulation ratios, high fuel pressures, concentrated fuel mist distribution, and are highly susceptible to fuel contamination, leading to coking and carbon buildup. In contrast, air atomizing nozzles have simple structures, lower machining requirements, are cheaper, and are less sensitive to fuel pressure and fuel contamination. However, their atomization quality is poor under low operating conditions, negatively impacting the combustion chamber's ignition and shutdown performance.

[0003] Single- or dual-oil-path centrifugal nozzles can provide good atomization performance under low operating conditions such as starting and idle, as seen in the single- and dual-oil-path centrifugal nozzles used in the recirculation combustors of the PT6 series engines. Furthermore, centrifugal nozzles are widely used in direct-flow combustors, such as those in the CFM56 series and F110 engines. However, centrifugal nozzles suffer from drawbacks such as a small fuel regulation ratio, high fuel pressure requirements, complex structure and difficult manufacturing, and a tendency to produce exhaust smoke. Recirculation combustors are generally suitable for small and medium-sized aero engines with very small fuel flow rates, making them highly costly. Using complex centrifugal nozzles would lead to manufacturing difficulties and high prices; and because the size of recirculation combustors in small and medium-sized aero engines is generally small, it is not feasible to use highly complex aerodynamic atomizing nozzles. Summary of the Invention

[0004] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0005] This disclosure provides a recirculation combustion device, the device comprising:

[0006] case;

[0007] A vortex generator is mounted on the housing.

[0008] An air atomizing nozzle is mounted on the vortex generator.

[0009] Furthermore, the eddy current generator includes:

[0010] A first-stage vortex generator, which has a fuel nozzle mounting hole for installing an air atomizing nozzle;

[0011] The venturi tube is installed on the first-stage eddy current generator;

[0012] A secondary eddy current generator is mounted on the venturi tube.

[0013] Furthermore, the first-stage vortex generator is provided with multiple vortex channels; the second-stage vortex generator is provided with multiple vortex channels.

[0014] Furthermore, the air atomizing nozzle includes:

[0015] The nozzle housing is equipped with an inner swirler inlet and an outer swirler air inlet.

[0016] Atomizing venturi tube is welded to the inner wall of the nozzle housing;

[0017] An internal vortex generator is welded to the inner wall of the atomizing venturi tube and has multiple vortex grooves on it.

[0018] A direct-fire nozzle is inserted into the orifice of the inner cyclone separator.

[0019] Furthermore, the direct-fire nozzle is provided with multiple circular holes with a diameter of 0.2mm-0.4mm.

[0020] Furthermore, the diameter of the air inlet of the internal cyclone separator ranges from 3mm to 6mm, and the number ranges from 1 to 3.

[0021] Furthermore, the diameter of the external swirling air inlet holes ranges from 1mm to 3mm, and the number ranges from 6 to 12.

[0022] Furthermore, the outer diameter of the direct-fire nozzle is D1, and the throat diameter of the atomizing venturi tube is D2, where D2 is 1.5-3 times D1.

[0023] Furthermore, the distance between the end face of the direct-fire nozzle and the throat of the atomizing venturi tube is L1, and the value of L1 ranges from 0.5mm to 2mm.

[0024] Furthermore, the angle of the convergent section of the atomizing venturi tube is α, with a value ranging from 40° to 80°, and the angle of the expanding section of the atomizing venturi tube is β, with a value ranging from 20° to 40°.

[0025] Furthermore, the tangential angle of the external swirling air inlet is the angle γ between the centerline and the horizontal, and the angle γ ranges from 20° to 50°.

[0026] The recirculation combustion device provided in this disclosure can achieve the following technical effects:

[0027] (1) The design of direct-injection nozzle with internal swirler, atomizing venturi tube and nozzle housing has a wide fuel adjustment range, is not sensitive to fuel pollution, and can adapt to a variety of liquid fuels.

[0028] (2) It has low requirements for fuel system pressure, uniform fuel and air mixing, wide spatial distribution of oil mist, good atomization effect in a wide working range, and can effectively reduce exhaust smoke under high power conditions;

[0029] (3) The direct-injection nozzle has a simple fuel flow path and is surrounded by a high-speed airflow, making it less prone to coking and carbon buildup.

[0030] (4) The air atomizing nozzle of the present invention has a simple structure, is easy to process, and has low cost. Attached Figure Description

[0031] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0032] Figure 1 This is a cross-sectional view of a recirculation combustion device provided in an embodiment of this disclosure;

[0033] Figure 2 This is a cross-sectional view of the vortex generator and air atomizing nozzle provided in the embodiments of this disclosure;

[0034] Figure 3 This is a cross-sectional view of the eddy current generator provided in an embodiment of this disclosure;

[0035] Figure 4 This is a cross-sectional view of an air atomizing nozzle provided in an embodiment of this disclosure;

[0036] Figure 5 This is a cross-sectional view of the external swirling air inlet provided in an embodiment of this disclosure;

[0037] Figure 6 This is a schematic diagram of the internal vortex generator provided in an embodiment of this disclosure.

[0038] In the diagram: 1. Diffuser, 2. Outer combustion chamber casing, 3. Inner combustion chamber casing, 4. Outer ring of the flame tube, 5. Inner ring of the flame tube, 6. Head ring of the flame tube, 7. Swirler, 8. Air atomizing nozzle, 9. Large bend, 10. Small bend, 11. Guide plate, 12. Fuel nozzle mounting hole, 13. First-stage swirler, 14. Venturi tube, 15. Second-stage swirler, 16. Direct-injection nozzle, 17. Inner swirler, 18. Atomizing Venturi tube, 19. Nozzle housing, 20. Inner swirler air inlet, 21. Outer swirling air inlet, 22. Swirl groove. Detailed Implementation

[0039] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0040] Combination Figure 1-6 As shown, this disclosure provides a recirculation combustion device, including:

[0041] case;

[0042] Eddy current generator 7 is mounted on the housing;

[0043] An air atomizing nozzle 8 is installed on the vortex generator 7.

[0044] In some embodiments of the present invention, the eddy current generator 7 includes:

[0045] A first-stage vortex generator 13 is provided with a fuel nozzle mounting hole 12 for mounting an air atomizing nozzle 8;

[0046] Venturi tube 14 is installed on the first-stage vortex generator 13;

[0047] A secondary eddy current generator 15 is mounted on the venturi tube 14.

[0048] In some embodiments of the present invention, the primary vortex generator 13 is provided with a plurality of vortex channels; the secondary vortex generator 15 is provided with a plurality of vortex channels.

[0049] In some embodiments of the present invention, the air atomizing nozzle 8 includes:

[0050] The nozzle housing 19 is equipped with an inner swirler inlet 20 and an outer swirler air inlet 21.

[0051] The atomizing venturi tube 18 is welded to the inner wall of the nozzle housing 19;

[0052] An inner vortex generator 17 is welded to the inner wall of the atomizing venturi tube 18, and has multiple vortex grooves 22 thereon;

[0053] A direct-fire nozzle 16 is inserted into the channel of the inner vortex 17.

[0054] In some embodiments of the present invention, the direct-fire nozzle 16 is provided with a plurality of circular holes with a diameter of 0.2 mm to 0.4 mm.

[0055] In some embodiments of the present invention, the diameter of the air inlet 20 of the internal cyclone separator ranges from 3mm to 6mm, and the number ranges from 1 to 3.

[0056] In some embodiments of the present invention, the diameter of the external swirling air inlet 21 ranges from 1 mm to 3 mm, and the number ranges from 6 to 12.

[0057] In some embodiments of the present invention, the outer diameter of the direct-fire nozzle 16 is D1, and the throat diameter of the atomizing venturi tube 18 is D2, where D2 is 1.5-3 times D1.

[0058] In some embodiments of the present invention, the distance between the end face of the direct-fire nozzle 16 and the throat of the atomizing venturi tube 18 is L1, and the value of L1 ranges from 0.5mm to 2mm.

[0059] In some embodiments of the present invention, the angle of the convergent section of the atomizing venturi tube 18 is α, and the value of α ranges from 40° to 80°; the angle of the expanding section of the atomizing venturi tube 18 is β, and the value of β ranges from 20° to 40°.

[0060] In some embodiments of the present invention, the tangential angle of the external swirling air inlet 21 is the angle γ between the centerline and the horizontal, and the angle γ ranges from 20° to 50°.

[0061] This invention employs a direct-fire nozzle matched with a simple air atomizing nozzle featuring a two-stage rotating airflow venturi structure. This design is simple in structure, easy to manufacture, and low in cost. It is also insensitive to fuel pressure and provides excellent atomization over a wide operating range. The air atomizing nozzle of this invention ensures uniform fuel-air mixing, is insensitive to liquid fuel type, has a wide fuel adjustment ratio, and is simple in structure, easy to manufacture, and low in cost.

[0062] A simple air atomizing nozzle and recirculation combustion chamber, mainly composed of a diffuser, combustion chamber casing, air atomizing nozzle, inner and outer rings of the flame tube, etc., the structure is shown in [see details]. Figure 1 .

[0063] Figure 1 The diagram shows a cross-sectional view of the combustion chamber. The combustion chamber adopts a single-annular cavity structure. The outer casing 2 and the inner casing 3 of the combustion chamber form the outer outline of the combustion chamber and are connected to the compressor and turbine at the front and rear. The incoming air from the compressor enters the combustion chamber after being decelerated and diffused by the diffuser 1. It then burns with the fuel, which has been atomized by the air atomizing nozzle 8 and the vortex generator 7, within the space surrounded by the outer ring 4, inner ring 5, head ring 6, large bend 9, small bend 10, and guide plate 11.

[0064] Figure 2 The image shown is a cross-sectional view of the combination of a vortex generator and an air atomizing nozzle. Figure 3This is a cross-sectional view of the vortex generator. The air atomizing nozzle 8 is inserted into the first-stage vortex generator 13 through the fuel nozzle mounting hole 12. The vortex generator 7 consists of a first-stage vortex generator 13, a venturi tube 14, and a second-stage vortex generator 15. The first-stage vortex generator 13 has multiple swirling channels machined on it (located between the fuel nozzle mounting hole 12 and the venturi tube 14) to form a rotating airflow. The second-stage vortex generator 15 has multiple swirling channels machined on it (located after the venturi tube 14) to form a rotating airflow. The first-stage vortex generator 13 is designed with a fuel nozzle mounting hole 12 for mounting the air atomizing nozzle 8.

[0065] Figure 4 This is a cross-sectional view of an air atomizing nozzle. Figure 5 This is a cross-sectional view of the external swirling air inlet. Figure 6This is a three-dimensional view of the inner vortex 17 of the air atomizing nozzle 8. The air atomizing nozzle 8 consists of a direct-shot nozzle 16, an inner vortex 17, an atomizing venturi tube 18, and a nozzle housing 19. A circular hole with a diameter of (0.2–0.4) mm is machined on the direct-shot nozzle 16. The inner vortex 17 is designed with swirl grooves 22, with 6–12 grooves. The nozzle housing is designed with inner vortex inlet holes 20 and outer swirling air inlet holes 21. The diameter of the inner vortex inlet holes 20 is (3–6) mm, and there are 1–3 inlet holes. The diameter of the outer swirling air inlet holes 21 is (1–3) mm, and there are 6–12 inlet holes. This design achieves the advantage of a large opening area for the inner vortex inlet holes, ensuring sufficient airflow into the inner vortex. The large number and small diameter of the outer swirling air inlet holes improve the uniformity of the swirling air. The direct-injection nozzle 16 passes through the inner vortex concentrator 17 and is fixed to the inner vortex concentrator 17 by welding. The inner vortex concentrator 17 is fixed to the atomizing venturi tube 18 by welding, and the atomizing venturi tube 18 is fixed to the nozzle housing 19. The outer diameter of the direct-injection nozzle 16 is D1, and the throat diameter of the atomizing venturi tube 18 is D2, where D2 is equal to (1.5 to 3) times D1. This value ensures that the swirling air can flow smoothly in the atomizing venturi tube and that there is sufficient airflow velocity in the atomizing venturi tube to provide sufficient air kinetic energy for fuel atomization. The distance from the end face of the direct-injection nozzle 16 to the throat of the atomizing venturi tube 18 is L1, where L1 is (0.5 to 2) mm. This value ensures that the fuel is well atomized before entering the atomizing venturi tube. The angle of the converging section of the atomizing venturi tube 18 is α, where α is (40°). ~80)° (This has the advantage of ensuring that the airflow is accelerated with less flow loss, thereby increasing the kinetic energy of the atomized air). The angle of the cross-sectional line of the expansion section of the atomizing venturi tube 18 is β, and the value of β is (20~40)° (This value has the advantage of increasing the atomization cone angle of the fuel on the one hand, improving the radial distribution uniformity of the fuel, and on the other hand, avoiding flow separation due to rapid deceleration and diffusion of the airflow). The external swirling air inlet 21 on the nozzle housing 19 has a certain tangential angle, and the angle between its centerline and the horizontal is γ, and the value of γ is (20~50)° (This value has the advantage of providing a suitable swirling intensity for the external swirling air).

[0066] When the combustion chamber is operating, fuel is injected through the direct-injection nozzle 16. A portion of the high-pressure air from the diffuser 1 enters the annular channel formed by the direct-injection nozzle 16 and the nozzle housing 19 through the inner swirler inlet 20, forming an inner swirling airflow through the inner swirler 17. This airflow is then accelerated by the atomizing venturi tube 18, resulting in initial fuel atomization. A portion of the high-pressure air from the diffuser 1 forms an outer swirling airflow through the outer swirling air inlet 21 on the nozzle housing 19. This outer swirling airflow interacts with the inner swirling airflow at the outlet of the atomizing venturi tube 18, further atomizing the fuel. The fuel-air mixture, atomized by the air atomizing nozzle 8, is then re-atomized by the vortex tube before entering the flame tube for combustion.

[0067] This device achieves the following: It employs a direct-injection nozzle with an internal vortex generator, an atomizing venturi tube, and a nozzle housing design, resulting in a wide fuel adjustment range, insensitivity to fuel contamination, and adaptability to various liquid fuels; it requires low fuel system pressure, ensures uniform fuel-air mixing, and produces a wide spatial distribution of fuel mist, providing excellent atomization over a broad operating range and effectively reducing exhaust smoke at high power levels; the direct-injection nozzle has a simple fuel flow path, surrounded by a high-speed airflow, making it less prone to coking and carbon buildup; the air atomizing nozzle of this invention has a simple structure, is easy to manufacture, and is low in cost.

[0068] The foregoing description and accompanying drawings fully illustrate embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included or substituted for parts and features of other embodiments. Embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from its scope. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A reflux combustion device, characterized in that, include: case; The vortex generator (7) is mounted on the housing; An air atomizing nozzle (8) is mounted on the vortex generator (7); the vortex generator (7) includes: A first-stage vortex generator (13) is provided with a fuel nozzle mounting hole (12) for mounting an air atomizing nozzle (8). A venturi tube (14) is mounted on the first-stage vortex generator (13); A secondary eddy current generator (15) is mounted on the venturi tube (14); The air atomizing nozzle (8) includes: The nozzle housing (19) is equipped with an inner swirler inlet (20) and an outer swirler air inlet (21). Atomizing Venturi tube (18) is welded to the inner wall of the nozzle housing (19); An inner vortex generator (17) is welded to the inner wall of the atomizing venturi tube (18) and has multiple vortex grooves (22) on it. A direct-fire nozzle (16) is inserted into the channel of the inner vortex (17).

2. The reflux combustion device according to claim 1, characterized in that, The first-stage vortex generator (13) is provided with multiple vortex channels; the second-stage vortex generator (15) is provided with multiple vortex channels.

3. The reflux combustion device according to claim 1, characterized in that, The direct-fire nozzle (16) is provided with multiple round holes with a diameter of 0.2mm-0.4mm.

4. The reflux combustion device according to claim 1, characterized in that, The diameter of the air inlet (20) of the internal cyclone separator ranges from 3mm to 6mm, and the number ranges from 1 to 3.

5. A reflux combustion device according to claim 1, characterized in that, The diameter of the external swirling air inlet (21) ranges from 1 mm to 3 mm, and the number ranges from 6 to 12.

6. A reflux combustion device according to claim 1, characterized in that, The outer diameter of the direct-fire nozzle (16) is D1, and the throat diameter of the atomizing venturi tube (18) is D2, which is 1.5-3 times that of D1.

7. A reflux combustion device according to claim 1, characterized in that, The distance between the end face of the direct-fire nozzle (16) and the throat of the atomizing venturi tube (18) is L1, and the value of L1 ranges from 0.5mm to 2mm.

8. A reflux combustion device according to claim 7, characterized in that, The angle of the convergent section of the atomizing venturi tube (18) is α, and the value of α ranges from 40° to 80°. The angle of the expansion section of the atomizing venturi tube (18) is β, and the value of β ranges from 20° to 40°.

9. A reflux combustion device according to claim 1, characterized in that, The tangential angle of the external swirling air inlet (21) is the angle γ between the centerline and the horizontal, and the angle γ ranges from 20° to 50°.

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