A turbofan engine flame tube structure for aircraft

Abstract

The present application provides a flame tube structure of a turbofan engine for aircraft, which belongs to the field of mechanical structure technology. The flame tube structure of the turbofan engine for aircraft includes: a cap, a head, an outer ring of the flame tube, an inner ring of the flame tube, an outer ring mounting edge and an inner ring mounting edge. One side of the head is connected to the cap, and the other side is connected to the outer ring of the flame tube and the inner ring of the flame tube. The center of the head is provided with a plurality of holes for assembling a swirler, and the swirler is provided with a centrifugal nozzle. The outer ring of the flame tube is connected to the outer ring mounting edge; the inner ring of the flame tube is connected to the inner ring mounting edge. The cost of the combustion chamber is 70% of the cost of the flame tube of a traditional turbofan engine of the same specification, because the product structure is simple, the manufacturing difficulty is low, the manufacturing compliance is good, and the precision is high; the combustion chamber outlet temperature is evenly distributed, and the flame tube wall temperature is low; at the same time, the nozzle and the swirler have high atomization quality and high reliability of high-altitude ignition.

Description

Technical Field

[0001] The present application belongs to the field of mechanical structure technology, and in particular, relates to a turbofan engine flame tube structure for an aircraft. Background Art

[0002] Aircraft turbofan engines have the advantage of good fuel economy and are often used as aircraft power. They are small in size, light in weight, simple in structure, low in cost, and easy to use. They require good high-altitude working performance and long storage time. Aircraft turbofan engines have small structural dimensions and high combustion chamber temperatures, resulting in high heat capacity and high wall temperatures of the flame tube. As aircraft turbofan engines pursue higher performance, the amount of cooling air used in the flame tube is very small, only 1 / 5 of the cooling air used in traditional flame tubes, making cooling design very difficult.

[0003] In the related technology, one method is to set advanced thermal insulation materials such as ceramics on the inner wall of the flame tube; another method is to use a double-layer or even multi-layer wall complex impact film cooling structure to reduce the temperature of the flame tube wall. However, these two methods are relatively expensive and cannot meet the low-cost requirements of turbofan engines for aircraft. Summary of the invention

[0004] In order to meet the requirements of low-cost and high-efficiency cooling of a turbofan engine for an aircraft, the present invention provides a flame tube structure of a turbofan engine for an aircraft, and the technical solution is as follows:

[0005] A turbofan engine flame tube structure for an aircraft comprises: a cap, a head, a flame tube outer ring, a flame tube inner ring, an outer ring mounting edge and an inner ring mounting edge,

[0006] One side of the head is connected to the cap, and the other side is connected to the outer ring of the flame tube and the inner ring of the flame tube. The center of the head is provided with multiple holes for assembling the swirler. The swirler is provided with a centrifugal nozzle. The outer ring of the flame tube is connected to the outer ring mounting edge; the inner ring of the flame tube is connected to the inner ring mounting edge.

[0007] Among them, the head is a circular ring with an I-shaped cross section. The cap is buckled on one side of the I-shape, and the outer ring on the other side of the I-shape is connected with the outer ring and inner ring of the flame tube.

[0008] Each cyclone is fixed with a centrifugal nozzle via a retaining ring.

[0009] Among them, the centrifugal nozzle is a single oil circuit centrifugal nozzle.

[0010] Among them, a single-side cooling hole is provided on the cyclone installation side for cooling between the two cyclone cylinders.

[0011] Among them, the outer ring of the flame tube and the inner ring of the flame tube are single-layer wall surfaces, and single-layer wall multi-inclined hole cooling is adopted.

[0012] The cap is connected to the head by two inner and outer segmented argon arc welding;

[0013] The head is connected to the outer ring of the flame tube and the inner ring of the flame tube by argon arc welding.

[0014] Wherein, the outer ring of the flame tube and the outer ring mounting edge are connected by argon arc butt welding;

[0015] The inner ring of the flame tube and the inner ring mounting edge are connected by argon arc butt welding.

[0016] Among them, the cyclone venturi adopts an expansion type with an expansion angle of 60°.

[0017] Among them, the cyclone is a stainless steel casting; the head, outer ring mounting edge and inner ring mounting edge are machined from GH3536 bars.

[0018] The present invention provides a turbofan engine flame tube structure for aircraft, and the combustion chamber cost is 70% of the cost of the conventional turbofan engine flame tube of the same specification. The product has a simple structure, low manufacturing difficulty, good manufacturing compliance and high precision; the combustion chamber outlet temperature is evenly distributed and the flame tube wall temperature is low; at the same time, the nozzle and the swirler have high atomization quality and high altitude ignition reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a turbofan engine flame tube for an aircraft provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 work are within the scope of protection of the present invention.

[0021] In the detailed description below, many specific details are provided in order to provide a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is intended only to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is by no means limited to any specific arrangement and method set forth below, but covers any improvements, substitutions and modifications of structures, methods, devices without departing from the spirit of the present invention. In the accompanying drawings and the following description, known structures and techniques are not shown to avoid unnecessary ambiguity of the present invention.

[0022] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the embodiments can refer to and quote each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] like Figure 1 As shown, this embodiment provides a flame tube structure of a turbofan engine for an aircraft, including: a cap 1, a head 2, a flame tube outer ring 5, a flame tube inner ring 6, an outer ring mounting edge 7 and an inner ring mounting edge 8.

[0024] The head 2 is annular, with 14 holes in the center for assembling the cyclone 3, and each hole is equipped with a cyclone 3. The cross section of the head 2 is I-shaped, and the cap 1 is buckled on one side of the I-shaped, and the cap 1 is connected to the head 2 through two inner and outer segmented argon arc welding. The outer ring on the other side of the I-shaped head 2 is butt-jointed with the outer ring 5 of the flame tube and connected by argon arc welding; the inner ring on the other side of the I-shaped head 2 is butt-jointed with the inner ring 6 of the flame tube and connected by argon arc welding.

[0025] The head 2 in this embodiment adopts an I-shaped structure with a thicker main body wall. Compared with sheet metal forming, the processing difficulty can be greatly reduced under the same positioning requirement, and the uniformity of the flame tube outlet temperature distribution can be improved; and the two ends of the I-shaped structure are respectively lap-welded to the cap 1, the flame tube outer ring 5, and the flame tube inner ring 6 to facilitate assembly and positioning; at the same time, air film cooling can be increased on the inner side of the two ends to reduce the wall temperature.

[0026] In this embodiment, the connection between the cap 1 and the head 2 is achieved by segmented argon arc welding, which reduces the welding surface, reduces deformation, reduces welding difficulty, and improves product stability while ensuring structural strength.

[0027] A small single oil path centrifugal nozzle 4 is fixed to each swirler 3 via a retaining ring, and the pipeline is connected to the combustion chamber casing via a cap 1.

[0028] In this embodiment, the flame tube has high integration, and the centrifugal nozzle 4 is integrated on the flame tube. The fuel enters the flame tube from the cap 1. Since the nozzle 4 is a single-oil centrifugal nozzle, it can achieve sufficient spray cone angle and atomization quality under low pressure, thereby ensuring the reliability of high-altitude ignition. At the same time, the centrifugal nozzle 4 has a simple structure and reduced cost.

[0029] In another embodiment, 4 cooling holes with a diameter of 1 mm are provided on one side of the cyclone 3, and 8 holes are provided on both sides for cooling the cylinder between the two cyclones. The cyclone 3 is provided with a single-side cooling hole on the mounting side, so as to achieve cooling between the two cyclone cylinders with the least amount of cold air and reduce the ablation of the cylinder wall.

[0030] The flame tube outer ring 5 is connected to the outer ring mounting edge 7 by argon arc butt welding; the flame tube inner ring 6 is connected to the inner ring mounting edge 8 by argon arc butt welding.

[0031] The airflow blows from the head 2 and is divided into three streams at the cap 1: the first stream enters the flame tube along the holes on the outer ring wall; the second stream enters the flame tube along the holes on the inner ring wall; the third stream enters from the holes on the cap 1 and enters the flame tube along the holes on the swirler 3 and the head 2. The fuel is sprayed into the flame tube along the pipeline through the centrifugal nozzle 4 to form a mist cone.

[0032] The swirler 3 is a stainless steel casting; the head 2, the outer ring mounting edge 7 and the inner ring mounting edge 8 are machined from GH3536 bars; the others (including the flame tube outer ring 5 and the flame tube inner ring 6) are GH3536 plates.

[0033] The flame tube outer ring 5 and the flame tube inner ring 6 are single-layer wall surfaces, and single-layer wall multi-inclined hole cooling is adopted, with a hole diameter of 0.4 and an angle of 20°.

[0034] In one possible implementation, the outer ring 5 of the flame tube is provided with 11 rows of cooling holes, and the inner ring 6 of the flame tube is provided with 12 rows of cooling holes, the hole diameter is 0.4, and they are inclined at an angle of 20° along the wall.

[0035] In another possible implementation, cooling holes are added to the rear section of the flame tube inner ring 6 for air film cooling.

[0036] In another embodiment, the hole spacing and row spacing of the multiple inclined holes in the flame tube outer ring 5 and the flame tube inner ring 6 are gradually increased along the axial direction; a row of cooling holes is arranged behind the large holes to reduce the wall temperature; the wall temperature can be lower than 1100°C when the cooling air volume is only 9%.

[0037] In another embodiment, the swirler 3 venturi tube is of expansion type with an expansion angle of 60°. In this way, the pneumatic atomization effect is good, the fuel atomization particle size is low, the processing difficulty is low, and the flow field stability is improved while the ignition reliability and outlet temperature distribution are improved.

[0038] In this embodiment, the multiple inclined holes at the rear of the igniter mounting seat have large apertures to reduce the clogging of the apertures by pyrotechnic igniter deposits and the impact on cooling efficiency.

[0039] Furthermore, the flame tube in this embodiment uses special tooling to control welding thermal deformation, and uses special tooling to detect the flame tube hole position, mounting seat position and mounting edge size, simplifying the three-coordinate measurement procedure to simulate tooling assembly, greatly reducing the detection difficulty, and reducing detection and management costs.

[0040] The flame tube structure of the turbofan engine for aircraft provided in this embodiment has a low flame tube cost. The cost can be reduced by 30% by adjusting materials, simplifying structures, reducing the number of parts, and reducing the difficulty of processing and welding. For example, the swirler 3 is processed by casting instead of bar machining; the outer ring mounting edge 7 and the inner ring mounting edge 8 and the head 2 are made of bar material instead of forgings, which saves costs; the flame tube outer ring 5 and the flame tube inner ring 6 are single-layer wall surfaces, which are directly formed by sheet metal, greatly reducing the number of parts such as cooling rings, reducing welding processes, and reducing welding costs; and the head 2 is simplified to a single-layer I-shaped structure, which reduces processing costs.

[0041] The structure of the present invention can be applied to turbofan engines for various aircraft.

[0042] The above only expresses the implementation methods of the present application, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. In addition, the parts that are not detailed in the present invention are all conventional technologies.

Claims

1. A turbofan engine flame tube structure for an aircraft, characterized in that: include: Cap, head, flame tube outer ring, flame tube inner ring, outer ring mounting edge and inner ring mounting edge, One side of the head is connected to the cap, and the other side is connected to the outer ring of the flame tube and the inner ring of the flame tube. The center of the head is provided with a plurality of holes for assembling the swirler. The swirler is provided with a centrifugal nozzle, which is a single oil circuit centrifugal nozzle. The outer ring of the flame tube is connected to the outer ring mounting edge; the inner ring of the flame tube is connected to the inner ring mounting edge. The head is annular, with an I-shaped cross section. The main body wall is relatively thick. The cap is buckled on one side of the I-shaped, and the outer ring on the other side of the I-shaped is butted against the outer ring and inner ring of the flame tube. Air film cooling is provided on the inner sides of both ends of the head to reduce the wall temperature. The cyclone installation side is equipped with a single-side cooling hole with a hole diameter of 1mm, and a total of 8 holes on both sides, which are used for cooling between the two cyclone cylinders; The airflow blows in from the head and is divided into three streams at the cap: the first stream enters the flame tube along the holes on the outer ring wall; the second stream enters the flame tube along the holes on the inner ring wall; the third stream enters from the holes on the cap, along the swirler and the holes on the head, and enters the flame tube. The fuel passes through the centrifugal nozzle along the pipeline to form a mist cone and is sprayed into the flame tube.

2. The aircraft turbofan engine flame tube structure according to claim 1, characterized in that: Each cyclone has a centrifugal nozzle fixed by a retaining ring.

3. The aircraft turbofan engine flame tube structure according to claim 1, characterized in that: The outer ring and inner ring of the flame tube are single-layer walls, and single-layer wall multi-inclined hole cooling is adopted.

4. The aircraft turbofan engine flame tube structure according to claim 1, characterized in that: The cap cover is connected to the head by two inner and outer segmented argon arc welding; The head is connected to the outer ring of the flame tube and the inner ring of the flame tube by argon arc welding.

5. The aircraft turbofan engine flame tube structure according to claim 1, characterized in that: The outer ring of the flame tube is butt-welded to the outer ring mounting edge by argon arc welding; The inner ring of the flame tube and the inner ring mounting edge are connected by argon arc butt welding.

6. The aircraft turbofan engine flame tube structure according to claim 1, characterized in that: The cyclone venturi is of expansion type with an expansion angle of 60°.

7. The aircraft turbofan engine flame tube structure according to claim 1, characterized in that: The cyclone is a stainless steel casting; the head, outer ring mounting edge and inner ring mounting edge are machined from GH3536 bar.

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