Air inlet uniformity diffuser and radial flow combustion chamber

Abstract

The application provides an air inlet uniform diffuser and a radial flow combustion chamber. The diffuser comprises a diffuser outer ring, a diffuser inner ring, and a plurality of diffuser blades. The two ends of the diffuser blades are connected to the inner wall of the diffuser outer ring and the outer wall of the diffuser inner ring respectively. The diffuser outer ring comprises a coaxially connected outer ring part and a bent body part. The free end of the bent body part towards the inner cavity of the combustion chamber extends to one side of the axis of the outer ring part. A first circular clamping groove is arranged on the bent body part. The free end of the outer ring part is connected to the external environment of the combustion chamber, and the free end of the bent body part is connected to the internal environment of the combustion chamber. When the airflow is in the hollow interlayer between the bent body part and the diffuser inner ring, the airflow is guided to flow to one side of the axis of the outer ring part, the flow direction of the airflow is changed, the airflow directly flows into the combustion chamber is avoided, and the problem of asymmetric air inlet of the two channels of the front and back walls and the head of the radial flow configuration combustion chamber is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of diffusers, and in particular relates to a diffuser with uniform air intake and a radial flow combustion chamber. Background Art

[0002] With advancements in aero-engine technology, the power-to-weight ratio of turboshaft engines continues to improve. This requires the development of combustion chambers with higher temperature rises and smaller axial footprints to achieve better engine performance. The current average combustor outlet temperature has reached 1900K and is expected to rise further in the future. This will increase the combustor's heat capacity, posing significant challenges to combustor design. Direct-flow and recirculating combustors are commonly used structural layouts in turboshaft engines. Direct-flow combustors occupy a large axial footprint, which is not conducive to improving the engine's rotordynamic performance; recirculating combustors have a large cooling area, which is not conducive to increasing the combustor's temperature rise. The radial-flow combustor, an innovative design based on the recirculating combustor, is designed to meet the performance requirements of higher-temperature-rise combustors. It also shortens the engine shafting and reduces the weight of the flame tube, which helps improve the power-to-weight ratio of the turboshaft engine.

[0003] Since the distance between the head of the flame tube of the radial flow combustion chamber and the diffuser inlet is relatively close, the airflow from the diffuser into the two channels on the front and rear walls of the flame tube is asymmetric, and the airflow entering the head is circumferentially asymmetric, resulting in poor uniformity of the flow field in the flame tube, which directly affects the full combustion and the uniformity of the outlet temperature field.

[0004] In view of this, overcoming the defects of the above-mentioned prior art is an urgent problem to be solved in this technical field. Summary of the Invention

[0005] In view of the above problems, the present invention proposes a diffuser with uniform air intake, comprising: a diffuser outer ring, diffuser blades, and a diffuser inner ring;

[0006] The diffuser outer ring and the diffuser inner ring are coaxially arranged and sleeved with a gap, and the ends of a plurality of diffuser blades arranged in a circumferential array are respectively connected to the inner wall of the diffuser outer ring and the outer wall of the diffuser inner ring, forming a hollow sandwich between the inner wall of the diffuser outer ring and the outer wall of the diffuser inner ring;

[0007] The outer ring of the diffuser includes an outer ring portion and a bent body portion that are coaxially connected. The free end of the bent body portion toward the inner cavity of the combustion chamber extends toward the side of the axis of the outer ring portion, and the tangent of the free end of the bent body portion forms a predetermined angle with the axis of the outer ring portion. Several first circular grooves for assembling nozzles are provided on the side wall of the bent body portion.

[0008] Furthermore, the two ends of the diffuser blade are respectively connected to the inner wall of the outer ring and the outer wall of the diffuser inner ring, and the connecting end surface of the outer ring and the curved body is flush with the end surface of the diffuser inner ring facing the curved body.

[0009] Furthermore, the side walls of the diffuser outer ring and the diffuser inner ring are respectively provided with a plurality of second through holes and first through holes arranged in a circumferential array, and the two ends of the diffuser blades are respectively inserted into the first through holes and the second through holes to form a fixed sleeve connection.

[0010] Furthermore, the cross section of the diffuser blade adopts a diamond structure, and the axis of the diffuser blade is arranged in parallel with the axis of the diffuser inner ring.

[0011] Furthermore, a first distance is maintained between a side of the diffuser inner ring facing the curved portion and an end portion of the diffuser blade on the same side, and the first distance is greater than or equal to 0.4 times the nozzle diameter.

[0012] Furthermore, the length of the diffuser blades toward the curved body portion is 1 to 2 times the nozzle diameter.

[0013] Furthermore, there is a second distance between one end of the diffuser inner ring facing the curved portion and the side wall of the first circular groove, and the second distance is greater than 0.3 times the nozzle diameter.

[0014] Furthermore, it further comprises second circular grooves, which are arranged circumferentially about the axis of the diffuser outer ring, and the angle between any second circular groove and two adjacent first circular grooves is consistent.

[0015] Furthermore, the side wall of the curved portion facing the hollow interlayer adopts an arc structure;

[0016] The starting point of the curved arc sidewall is spaced a third distance from the axis of the first circular slot, the third distance is 0 to 0.2 times the nozzle diameter, and the radius of the curved arc sidewall is 0.525 to 0.6 times the nozzle diameter.

[0017] The present invention also provides a radial flow combustion chamber, comprising the diffuser with uniform air intake as described above.

[0018] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0019] The diffuser with uniform air intake of the present invention is connected to the external environment of the combustion chamber by the free end of the outer ring part, and is connected to the environment of the inner cavity of the combustion chamber by the free end of the bent body part; so that the airflow maintains horizontal flow in the hollow interlayer between the outer ring part and the inner ring of the diffuser; when the airflow is in the hollow interlayer between the bent body part and the inner ring of the diffuser, the tangent of the free end of the bent body part and the axial line of the outer ring part form a predetermined angle, thereby guiding the airflow to flow to one side of the axial line of the outer ring part, realizing the change of the flow direction of the airflow, avoiding the airflow directly flowing into the combustion chamber, causing the problem of asymmetric air intake of the two channels on the front and rear walls of the radial flow configuration combustion chamber and the head, and improving the uniformity of the temperature field at the outlet of the combustion chamber.

[0020] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A cross-sectional schematic diagram of a diffuser with uniform air intake according to an embodiment of the present invention is shown;

[0023] Figure 2 A schematic structural diagram of the diffuser outer ring in an embodiment of the present invention is shown;

[0024] Figure 3 FIG2 shows a front view schematic diagram of the diffuser outer ring in an embodiment of the present invention;

[0025] Figure 4 A cross-sectional schematic diagram of the outer ring of the diffuser in an embodiment of the present invention is shown;

[0026] Figure 5 A schematic top view of the outer ring of the diffuser in an embodiment of the present invention is shown;

[0027] Figure 6 A schematic structural diagram of the inner ring of the diffuser in an embodiment of the present invention is shown;

[0028] Figure 7 A schematic structural diagram of a diffuser blade in an embodiment of the present invention is shown;

[0029] Figure 8 A schematic diagram of the use status of the diffuser and the radial flow combustion chamber in an embodiment of the present invention is shown.

[0030] In the figure, diffuser 1, diffuser outer ring 101, outer ring portion 1011, curved body portion 1012, diffuser blades 102, diffuser inner ring 103, first through hole 104, second through hole 105, first circular groove 106, second circular groove 107, front wall casing 2, rear wall casing 3, flame tube front wall 4, flame tube rear wall 5, nozzle 6, and head heat shield 7. DETAILED DESCRIPTION

[0031] The following description provides many different embodiments or examples for implementing different features of the present invention. The components and arrangements described in the following specific examples are only used to simplify the present invention and are only used as examples, not to limit the present invention.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] The present invention provides a diffuser with uniform air intake, referring to Figure 1 In the example shown, the diffuser 1 is installed at the inlet of the combustion chamber and is assembled with the nozzle 6 to guide the air flow of the compressor to the inner cavity of the combustion chamber for ignition.

[0034] Figure 1 FIG. 1 shows a cross-sectional schematic diagram of a diffuser with uniform air intake in an embodiment of the present invention, with reference to FIG. Figures 1 to 6 , the diffuser 1 includes: a diffuser outer ring 101, diffuser blades 102, and a diffuser inner ring 103;

[0035] The diffuser outer ring 101 and the diffuser inner ring 103 are coaxially arranged and interlocked with each other. The ends of a plurality of diffuser blades 102 arranged in a circumferential array are respectively connected to the inner wall of the diffuser outer ring 101 and the outer wall of the diffuser inner ring 103. A hollow interlayer is formed between the inner wall of the diffuser outer ring 101 and the outer wall of the diffuser inner ring 103 to guide the airflow output by the compressor through the hollow interlayer into the combustion chamber cavity.

[0036] The diffuser outer ring 101 includes an outer ring portion 1011 and a bent portion 1012 that are coaxially connected. The free end of the bent portion 1012 toward the inner cavity of the combustion chamber extends toward the side of the axis of the outer ring portion 1011, and the tangent of the free end of the bent portion 1012 forms a predetermined angle with the axis of the outer ring portion 1011. A plurality of first circular grooves 106 for assembling the nozzle 6 are provided on the side wall of the bent portion 1012.

[0037] During actual use of the diffuser of the present application, the outer wall of the diffuser outer ring 101 and the inner wall of the diffuser inner ring 103 are respectively fitted and sleeved with the inner wall of the combustion chamber inlet, and the diffuser and the combustion chamber are fixed by bolts.

[0038] The free end of the outer ring portion 1011 is connected to the external environment of the combustion chamber, and the free end of the curved portion 1012 is connected to the environment of the combustion chamber's inner cavity. When the external airflow passes through the hollow interlayer between the inner wall of the diffuser outer ring 101 and the outer wall of the diffuser inner ring 103, the airflow maintains a horizontal flow in the hollow interlayer between the outer ring portion 1011 and the diffuser inner ring 103. When the airflow is in the hollow interlayer between the curved portion 1012 and the diffuser inner ring 103, the tangent line of the free end of the curved portion 1012 forms a predetermined angle with the axis of the outer ring portion 1011, thereby guiding the airflow to flow toward the axis of the outer ring portion 1011, thereby changing the flow direction of the airflow and preventing the airflow from flowing directly into the combustion chamber, which would cause the asymmetric airflow intake problem in the two channels on the front and rear walls of the radial flow configuration combustion chamber and the head.

[0039] The diffuser proposed in the present invention guides the airflow to turn and flow toward the middle position of the combustion chamber cavity, causing the airflow to split into two symmetrical airflows at the middle position, so that the airflow in the two channels on the front and rear walls of the combustion chamber and the head remains symmetrical, thereby improving the uniformity of the temperature field at the combustion chamber outlet.

[0040] In this embodiment, the two ends of the diffuser blade 102 are connected to the inner wall of the outer ring portion 1011 and the outer wall of the diffuser inner ring 103 respectively. The connecting end surface of the outer ring portion 1011 and the curved portion 1012 is flush with the end surface of the diffuser inner ring 103 facing the curved portion 1012.

[0041] refer to Figure 1 , shows a schematic cross-sectional view of the diffuser outer ring 101 and the diffuser inner ring 103. In the figure, the cross sections of the outer ring portion 1011 and the diffuser inner ring 103 are vertically aligned, and there is no vertical alignment interval between the cross sections of the curved portion 1012 and the diffuser inner ring 103. By limiting the length of the diffuser inner ring 103, a turning space is provided for the curved portion 1012 to guide the airflow, thereby ensuring smooth turning and flow of the airflow.

[0042] Correspondingly, the side walls of the diffuser outer ring 101 and the diffuser inner ring 103 are respectively provided with a plurality of second through holes 105 and first through holes 104 arranged in a circumferential array, and the two ends of the diffuser blades 102 are respectively inserted into the first through holes 104 and the second through holes 105 to form a fixed socket.

[0043] exist Figure 4 and Figure 6In the example shown, the plurality of first through holes 104 and the plurality of second through holes 105 are arranged in a one-to-one correspondence; in the production and processing of the diffuser of the present application, the first through holes 104 and the second through holes 105 are first opened, and the two ends of the diffuser blade 102 are respectively inserted into the first through holes 104 and the second through holes 105 to form a preliminary fixation; illustratively, welding is used to achieve the fixation of the diffuser blade 102 to the first through holes 104 and the second through holes 105, and the welding operation can be performed directly on the outer wall of the diffuser outer ring 101 and the inner wall of the diffuser inner ring 103, which reduces the processing difficulty of the diffuser itself, and only requires reasonable polishing afterwards without affecting the use of the diffuser.

[0044] Among them, reference Figure 7 The cross section of the diffuser blade 102 adopts a diamond structure, and the axis of the diffuser blade 102 is arranged parallel to the axis of the diffuser inner ring 103. On the basis of using the diffuser blade 102 to connect the diffuser outer ring 101 and the diffuser inner ring 103 to form a whole, the diamond structure of the diffuser blade 102 itself realizes the rectification effect of the airflow with a circumferential airflow angle output by the compressor, reduces the circumferential component velocity of the airflow output by the compressor, and improves the stability of the airflow in the process of entering the combustion chamber cavity and the stability of the airflow in the combustion chamber cavity.

[0045] The side of the diffuser inner ring 103 facing the curved portion 1012 maintains a first spacing L1 with the end of the diffuser blade 102 on the same side. This spacing L1 is set to be greater than or equal to 0.4 times the diameter D0 of the nozzle 6. For example, the first spacing L1 is 0.4 times the diameter D0 of the nozzle 6. After the diffuser blade 102 changes the circumferential flow angle of the compressor output airflow, a certain buffer space is provided before the changed airflow contacts the curved portion 1012, further improving the stability of the airflow passing through the hollow interlayer.

[0046] Correspondingly, the length of the diffuser blade 102 toward the curved portion 1012 is 1 to 2 times the diameter D0 of the nozzle 6 to ensure that the diffuser blade 102 has sufficient depth to ensure the effect of changing the circumferential airflow angle.

[0047] exist Figure 1 In the example shown, in combination with the design of maintaining a first spacing L1 between one side of the diffuser blade 102 and the end portion on the same side of the diffuser blade 102, a second spacing L2 is further set between the end of the diffuser inner ring 103 facing the curved portion 1012 and the side wall of the first circular groove 106. The second spacing L2 is greater than 0.3 times the diameter D0 of the nozzle 6.

[0048] While further increasing the airflow buffer space, the first circular groove 106 is provided to limit the position of the nozzle 6, thereby preventing the side wall of the nozzle 6 from abutting against the end wall of the diffuser inner ring 103 and obstructing the flow of airflow.

[0049] refer to Figure 1 、 Figure 2 and Figure 3 In order to ensure the circumferential consistency of the air intake of the nozzle 6, the axis of the first circular groove 106 is coaxially arranged with the axis of the nozzle 6.

[0050] Also refer to Figure 5 Taking into account the thermal expansion and deformation that may occur in the flame tube under high temperature conditions, a gap of 0.4 mm to 0.5 mm is reserved between the inner wall of the first circular groove 106 and the side wall of the nozzle 6, that is, the difference between the diameter D1 of the inner wall of the first circular groove 106 and the outer diameter D0 of the nozzle 6 is 0.8 to 1.0 mm, so that the first circular groove 106 and the nozzle 6 are assembled with a gap, providing sufficient space for the expansion and deformation of the flame tube.

[0051] Correspondingly, in the present application, a plurality of first circular grooves 106 are arranged in a circular array about the axis of the diffuser outer ring 101. When designing the diffuser outer ring 101, it is necessary to first obtain a set number of nozzles 6 as M, and calculate the angle between the centers of adjacent first circular grooves 106 as θ = 360° / (2M).

[0052] In addition, reference Figure 3 Due to monitoring requirements, a test probe is also installed on the combustion chamber casing to monitor the area near the diffuser outlet. A second circular slot 107 is added to mate with the test probe. These slots are arranged circumferentially about the axis of the diffuser outer ring 101, and the angle between any second circular slot 107 and two adjacent first circular slots 106 remains consistent.

[0053] In this embodiment, reference Figure 4 In order to avoid the formation of a low-speed recirculation zone when the airflow is guided by the curved portion 1012 to turn, the side wall of the curved portion 1012 facing the hollow interlayer adopts an arc structure to guide the fluid.

[0054] It should be noted that the combustion chamber includes a combustion chamber front wall casing 2, a combustion chamber rear wall casing 3, a flame tube front wall 4, a flame tube rear wall 5 and a head heat insulation plate 7. The incoming air from the compressor enters the combustion chamber after deceleration and compression through the diffuser 1, and is fully mixed with the fuel in the space surrounded by the flame tube front wall 4, the flame tube rear wall 5 and the head heat insulation plate 7 to complete the combustion process.

[0055] Considering that the fuel nozzle 6 is located at the center of the head heat shield 7, the outer ring portion 1011 and the inner ring 103 of the diffuser 1 are arranged parallel to the head heat shield 7. The arc angle of the arc side wall of the curved portion 1012 is 90°, which achieves the effect of guiding the airflow to turn 90°, so that the direction of the airflow changes from a direction perpendicular to the axis of the nozzle 6 to a direction consistent with the direction axis of the nozzle 6.

[0056] At the same time, the starting point of the arc side wall of the curved body portion 1012 is spaced a third distance from the axial centerline of the first circular slot 106 , and the third distance is 0 to 0.2 times the diameter of the nozzle 6 . The radius of the arc side wall of the curved body portion 1012 is 0.525 to 0.6 times the diameter of the nozzle 6 .

[0057] The diffuser proposed in the present invention guides the airflow to the middle position of the inner cavity of the combustion chamber by guiding the airflow, so as to promote the airflow to the middle position of the head heat insulation plate 7 and maintain the same direction as the output end of the nozzle 6, so that the airflow is evenly divided into two symmetrical airflows at the middle position of the head heat insulation plate 7. The two symmetrical airflows flow into the front wall casing 2 and the rear wall casing 3 respectively under the obstruction of the head heat insulation plate 7, thereby realizing a symmetrical and stable flow state of the airflow and improving the uniformity of the temperature field at the combustion chamber outlet.

[0058] In addition, reference Figure 8 The present invention also proposes a radial flow combustion chamber, including a diffuser with uniform air intake as described above. In the figure, the arrows indicate the flow direction of the airflow, and it can be seen that the single airflow is divided into two symmetrical airflows through the diffuser 1.

[0059] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the specified features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0060] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical, electrical, or intercommunication connections; direct or indirect connections through an intermediary; and may encompass internal connectivity between multiple components or interactions between multiple components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0061] In the description of the present invention, it should be understood that all terms used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and cannot be understood as a limitation on the present invention.

[0062] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A diffuser with uniform air intake, for installation at the inlet of a combustion chamber and forming an assembly with a nozzle (6), characterized in that: The diffuser comprises: a diffuser outer ring (101), diffuser blades (102), and a diffuser inner ring (103); The diffuser outer ring (101) and the diffuser inner ring (103) are coaxially arranged and sleeved in a gap manner, and the two ends of a plurality of diffuser blades (102) arranged in a circumferential array are respectively connected to the inner wall of the diffuser outer ring (101) and the outer wall of the diffuser inner ring (103), forming a hollow interlayer between the inner wall of the diffuser outer ring (101) and the outer wall of the diffuser inner ring (103); The diffuser outer ring (101) comprises an outer ring portion (1011) and a bent portion (1012) connected coaxially, wherein the bent portion (1012) extends toward the free end of the combustion chamber inner cavity toward the side of the axis of the outer ring portion (1011), and the tangent line of the free end of the bent portion (1012) forms a predetermined angle with the axis of the outer ring portion (1011), and a plurality of first circular grooves (106) for assembling the nozzle (6) are provided on the side wall of the bent portion (1012).

2. The diffuser with uniform air intake according to claim 1, characterized in that: The two ends of the diffuser blade (102) are respectively connected to the inner wall of the outer ring portion (1011) and the outer wall of the diffuser inner ring (103); the connecting end surface of the outer ring portion (1011) and the curved body portion (1012) is flush with the end surface of the diffuser inner ring (103) facing the curved body portion (1012).

3. The diffuser with uniform air intake according to claim 2, characterized in that: The side walls of the diffuser outer ring (101) and the diffuser inner ring (103) are respectively provided with a plurality of second through holes (105) and first through holes (104) arranged in a circumferential array, and the two ends of the diffuser blade (102) are respectively inserted into the first through hole (104) and the second through hole (105) to form a fixed sleeve connection.

4. The diffuser with uniform air intake according to claim 2, characterized in that: The cross section of the diffuser blade (102) adopts a diamond structure, and the axis of the diffuser blade (102) is arranged in parallel with the axis of the diffuser inner ring (103).

5. The diffuser with uniform air intake according to claim 4, characterized in that: The side of the diffuser inner ring (103) facing the curved portion (1012) maintains a first spacing with the end portion on the same side of the diffuser blade (102), and the first spacing is greater than or equal to 0.4 times the diameter of the nozzle (6).

6. The diffuser with uniform air intake according to claim 4, characterized in that: The length of the diffuser blade (102) in the direction toward the curved portion (1012) is 1 to 2 times the diameter of the nozzle (6).

7. The diffuser with uniform air intake according to claim 6, characterized in that: A second distance is provided between one end of the diffuser inner ring (103) facing the curved portion (1012) and the side wall of the first circular groove (106), and the second distance is greater than 0.3 times the diameter of the nozzle (6).

8. The diffuser with uniform air intake according to claim 1, characterized in that: It also includes second circular grooves (107), which are arranged circumferentially about the axis of the diffuser outer ring (101), and the angle between any second circular groove (107) and two adjacent first circular grooves (106) remains consistent.

9. The diffuser with uniform air intake according to claim 1, characterized in that: The side wall of the curved portion (1012) facing the hollow interlayer adopts an arc structure; The starting point of the arc side wall of the bend (1012) is spaced from the axis of the first circular groove (106) by a third distance, the third distance being 0 to 0.2 times the diameter of the nozzle (6), and the radius of the arc side wall of the bend (1012) being 0.525 to 0.6 times the diameter of the nozzle (6).

10. A radial flow combustion chamber, characterized in that: The invention comprises a diffuser with uniform air intake as described in any one of claims 1 to 9.

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