Evaporating pipe oil supply device and combustion chamber

Abstract

The invention relates to the technical field of aero-engines, and discloses an evaporation pipe oil supply device and a combustion chamber. The evaporation pipe oil supply device comprises a pipe body and an oil conveying pipe. The pipe body comprises an atomization section, the atomization section is provided with a main air inlet formed in the axial direction and a plurality of sub air inlets formed in the circumferential direction, and the airflow direction of the main air inlet and the airflow direction of the sub air inlets intersect to form shear airflow. The oil conveying pipe comprises an oil spraying part which is arranged towards the main air inlet of the atomization section and used for spraying fuel oil to the inner wall of the atomization section. By means of the design that axial air inflow and circumferential multi-strand air inflow intersect, the atomization crushing effect of fuel oil is remarkably enhanced through the multiple airflow shearing effect in the evaporation pipe, the oil-gas mixing uniformity is improved, the ignition performance and combustion efficiency of the combustion chamber under the conditions of low air pressure and low flow speed are effectively improved, and the combustion efficiency of the combustion chamber is improved. And meanwhile, the advantages of simple structure and low cost of the evaporation pipe are kept.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, specifically to an evaporator fuel supply device and a combustion chamber. Background Technology

[0002] In the field of aero-engine technology, the evaporator fuel supply device is a simple and low-cost fuel atomization and mixing device. It is usually partially placed inside the flame tube. It uses high-temperature gas to heat the tube wall, causing the fuel inside the tube to evaporate and mix with air to form a premixed gas that is then injected into the combustion zone.

[0003] However, the atomization process of traditional evaporator tubes relies excessively on the heating effect of the high-temperature combustion gas inside the flame tube, while the aerodynamic atomization effect provided by its air intake structure is limited. This is particularly evident under operating conditions such as low air pressure and low flow rate, resulting in poor fuel atomization quality, large fuel droplet size, uneven fuel-air mixing, and consequently, problems such as difficulty in ignition, unstable combustion, and reduced combustion efficiency. Summary of the Invention

[0004] In view of this, the present invention provides an evaporator oil supply device and a combustion chamber to solve the problem of "poor atomization quality of the evaporator oil supply device under certain operating conditions".

[0005] In a first aspect, the present invention provides an evaporator tube oil supply device, which includes a tube body and an oil supply pipe; the tube body includes an atomizing section, the atomizing section is provided with a main air inlet and a plurality of sub-air inlets, the main air inlet is arranged along the axial direction of the atomizing section, the plurality of sub-air inlets are arranged along the circumferential direction of the atomizing section, and the airflow directions of the main air inlet and the sub-air inlets intersect; the oil supply pipe includes an oil spraying section, the oil spraying section facing the main air inlet of the atomizing section.

[0006] In one optional embodiment, the atomizing section is provided with a flow guiding area, and a sub-inlet is provided in the flow guiding area. The flow guiding area is provided with a multi-stage flow guiding structure group, which includes multiple flow guiding vanes. Each flow guiding vane corresponds to a sub-inlet. The flow guiding vane is set at an angle to the atomizing section and faces the end away from the main inlet. The flow guiding vane partially covers the sub-inlet.

[0007] In one optional embodiment, the flow guiding structure groups are distributed at intervals along the axial direction of the flow guiding area, and adjacent two-stage flow guiding structure groups are staggered in the circumferential direction, and the angle between the flow guiding vanes and the inner wall of the flow guiding area gradually increases along the airflow direction of the main air inlet.

[0008] In one alternative implementation, the atomizing section is further provided with a transition zone, which connects the main air inlet and the guide zone, and the diameter of the transition zone is increased from the main air inlet to the guide zone.

[0009] In one optional embodiment, the pipe body is further provided with a mixing section, one end of which has an air outlet and the other end is connected to the guide zone, and the mixing section and the guide zone are at least partially set at an angle.

[0010] In one alternative embodiment, the temperature of the mixing section is higher than that of the atomization section.

[0011] In one optional embodiment, the fuel injection section extends along the axial direction of the atomizing section into the transition zone, and the fuel injection section is provided with at least one fuel injection port, the axial direction of the fuel injection port being set at an angle to the axial direction of the atomizing section.

[0012] In a second aspect, the present invention also provides a combustion chamber, comprising: a casing, a flame tube, and an evaporator oil supply device as described in the first aspect; the casing includes an outer casing and an inner casing, which are coaxially arranged and connected to each other, forming an annular airflow channel between them; the flame tube is disposed in the airflow channel and connected to the casing; the pipe body of the evaporator oil supply device is mounted on the flame tube, and the mixing section extends into the interior of the flame tube.

[0013] In one optional embodiment, the flame tube is provided with multiple evaporator oil supply devices, and the evaporator oil supply devices are distributed at intervals along the circumference of the flame tube, wherein the oil supply pipe of each evaporator oil supply device is connected to the casing.

[0014] In one alternative embodiment, the flame tube has a combustion zone, the mixing section is a bent pipe section, and the air outlet is axially oriented toward the combustion zone.

[0015] The technical solution proposed in this application has at least the following technical effects:

[0016] In this application, by making the airflow direction of the main air inlet arranged along the axial direction of the pipe body intersect with the airflow direction of multiple sub-air inlets arranged along the circumference of the pipe body, a multi-directional shear airflow is formed in the atomization section of the evaporator pipe fuel supply device, which can significantly enhance the aerodynamic breaking effect of fuel and improve its atomization fineness and uniformity under conditions such as low air pressure and low flow rate. While maintaining the advantages of simplicity and low cost of the evaporator pipe fuel supply device, this application optimizes the fuel-air mixing process, thereby helping to improve the ignition success rate and combustion stability, and improve combustion efficiency. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of an evaporator oil supply device according to an embodiment of the present invention; Figure 2 This is a structural diagram of the atomizing section of an evaporator oil supply device according to an embodiment of the present invention; Figure 3 This is a structural diagram of the oil supply pipe of an evaporator oil supply device according to an embodiment of the present invention; Figure 4 This is a structural diagram of a combustion chamber according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the flame tube structure of a combustion chamber according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the airflow channel of a combustion chamber according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Pipe body; 101. Atomizing section; 1011. Guide zone; 10111. Sub-inlet; 10112. Guide structure assembly; 10112-1. Guide vane; 1012. Main inlet; 1013. Transition zone; 102. Mixing section; 1021. Outlet; 2. Fuel supply pipe; 201. Fuel injection section; 202. Fuel injection nozzle; 3. Casing; 301. Outer casing; 302. Inner casing; 4. Flame tube; 401. Combustion zone; 5. Airflow channel. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to impose strict limitations on the technical solutions unless the context clearly indicates otherwise. For example, the use of "a," "an," and "the" to modify a feature does not preclude the possibility that the feature may be plural in other embodiments.

[0022] It should be understood that the terms "comprising," "including," and "having" are open-ended, indicating the presence of the stated features but not excluding the possibility of other features in the embodiment. Similarly, the use of terms such as "first," "second," etc., to describe multiple features only indicates the distinction between one feature and another, and such terms do not imply order or sequence unless explicitly stated in the context.

[0023] It should be understood that, unless the context clearly indicates otherwise, the terms "setup," "connection," and "installation" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrated connection; they can refer to a direct connection or an indirect connection via a medium. Those skilled in the art will understand the specific meaning of these terms in this document based on the specific circumstances.

[0024] In addition, for ease of description, the text will use terms of spatial relative relationship to describe the position of one feature relative to another feature, such as "inner", "outer", "end", "side", "upper", "middle", "lower", "high", "low", "axial", "circumferential", "radial", "horizontal", "vertical", "first direction", "second direction", etc. It can be understood that the spatial relative relationship between two features should include other specific situations besides those shown in the accompanying drawings of the specification.

[0025] The embodiments of this application are described below with reference to the accompanying drawings. It can be understood that the technical features involved in the different embodiments described below can be combined with each other as long as they do not conflict with each other.

[0026] The following is combined Figures 1 to 6 The following describes embodiments of the present invention.

[0027] According to an embodiment of the present invention, in a first aspect, referring to Figures 1 to 3 An evaporator tube oil supply device is provided, comprising: a tube body 1 and an oil supply pipe 2; the tube body 1 includes an atomizing section 101, the atomizing section 101 is provided with a main air inlet 1012 and a plurality of sub-air inlets 10111, the main air inlet 1012 is arranged along the axial direction of the atomizing section 101, the plurality of sub-air inlets 10111 are arranged along the circumferential direction of the atomizing section 101, and the airflow directions of the main air inlet 1012 and the sub-air inlets 10111 intersect; the oil supply pipe 2 includes an oil spraying section 201, the oil spraying section 201 facing the main air inlet 1012 of the atomizing section 101.

[0028] In this embodiment, the evaporator oil supply device includes a pipe body 1 and an oil supply pipe 2. The pipe body 1 mainly includes an atomizing section 101. One end of the atomizing section 101 is provided with a main air inlet 1012 extending axially. Multiple sub-air inlets 10111 are circumferentially opened on its pipe wall. The airflow direction entering from the sub-air inlets 10111 intersects with the axial mainstream direction entering from the main air inlet 1012. The oil injection section 201 of the oil supply pipe 2 extends into the main air inlet 1012, and the oil injection section 201 at its end is arranged along the axial direction of the main air inlet 1012.

[0029] Furthermore, the fuel injection section 201 sprays fuel onto the inner wall of the pipe body 1, so that the fuel impacts the wall after being sprayed out and is fully broken and atomized under the shearing action formed by the intersecting airflow of the main air intake 1012 and the sub-air intake 10111.

[0030] It should be noted that the oil pipeline 2 is connected to an external oil supply device to enable oil spraying into the pipeline 1.

[0031] In one embodiment, refer to Figure 1 and Figure 2 The atomizing section 101 is provided with a flow guiding area 1011, and a sub-inlet 10111 is provided in the flow guiding area 1011. The flow guiding area 1011 is provided with a multi-stage flow guiding structure group 10112. The flow guiding structure group 10112 includes multiple flow guiding vanes 10112-1. Each flow guiding vane 10112-1 corresponds to a sub-inlet 10111. The flow guiding vane 10112-1 is set at an angle to the atomizing section 101 and faces the end away from the main inlet 1012. The flow guiding vane 10112-1 partially covers the sub-inlet 10111.

[0032] In this embodiment, multiple levels of flow guiding structures 10112 are arranged axially within the flow guiding zone 1011. Each level of flow guiding structure 10112 consists of multiple circumferentially spaced flow guiding vanes 10112-1. Each flow guiding vane 10112-1 corresponds to a sub-inlet 10111 opened on the pipe wall. The flow guiding vane 10112-1 protrudes from the pipe wall into the pipe, its surface forming an acute angle with the inner wall surface of the atomizing section 101, and extends in a direction away from the main inlet 1012, thereby partially covering its corresponding sub-inlet 10111 to guide the incoming airflow, so that the airflow direction of the sub-inlet 10111 intersects with the airflow formed by the main inlet 1012.

[0033] Optionally, the shape of the guide vane 10112-1 may include, but is not limited to, a fan shape, a leaf shape, or a semi-circle.

[0034] Understandably, the flow guide vane 10112-1 and the sub-inlet 10111 are constructed by stamping and rotating the flow guide region 1011.

[0035] In one embodiment, refer to Figure 1 and Figure 2 The flow guiding structures are distributed at intervals along the axial direction of the flow guiding area 1011, and the adjacent two-stage flow guiding structures are staggered in the circumferential direction. The angle between the flow guiding structure and the inner wall of the flow guiding area 1011 gradually increases along the airflow direction of the main air inlet 1012.

[0036] In this embodiment, in the circumferential direction of the pipe body 1, the guide vanes 10112-1 in adjacent two-stage guide structure groups 10112 are arranged alternately. Along the airflow direction, the tilt angle of each stage of guide vanes 10112-1 gradually increases, which can enhance the shearing effect between the airflow of the sub-inlet 10111 and the airflow of the main inlet 1012. It can also gradually form a wall-adhering vortex inside the pipe body 1 from the wall surface, improve the interaction between the airflow in the central region inside the pipe body 1 and the airflow near the wall surface, thereby achieving multi-stage, efficient successive breaking atomization, and significantly improving the atomization fineness and uniformity of the fuel.

[0037] It should be noted that during the fuel supply process, the fuel first impacts the root of the guide vane 10112-1. Affected by the flow of the guide vane 10112-1, the fuel flows along the guide vane 10112-1 and then detaches from the guide vane 10112-1 at the end. At this time, the fuel that has detached from the guide vane 10112-1 is exactly in the area where the airflow of the main air intake 1012 and the airflow of the sub-air intake 10111 interacts. Under the influence of the airflow shearing, the fuel will be further broken into droplets.

[0038] Understandably, since the airflow pressure inside pipe 1 is lower than the external airflow pressure, the overall movement direction of the airflow and oil droplets inside pipe 1 is towards the downstream part of pipe 1.

[0039] Specifically, the flow guiding structure group 10112 is arranged in 5 to 8 stages along the axial direction of the flow guiding area 1011, and each stage of the flow guiding structure group 10112 is arranged with 4 to 6 flow guiding vanes 10112-1 in the circumferential position of the flow guiding area 1011.

[0040] Specifically, the angle of the guide vane 10112-1 increases step by step, and the last stage, that is, the stage guide vane 10112-1 farthest from the main air intake 1012, has an angle of 90° with the axis of the guide area 1011.

[0041] In one embodiment, refer to Figure 1 and Figure 2 The atomizing section 101 is also provided with a transition zone 1013, which connects the main air inlet 1012 and the guide zone 1011. The diameter of the transition zone 1013 is increased from the main air inlet 1012 to the guide zone 1011.

[0042] In this embodiment, the atomizing section 101 is further provided with a transition zone 1013 between its main air inlet 1012 and the guide zone 1011. The diameter of the transition zone 1013 smoothly expands from the main air inlet 1012 to the guide zone 1011 along the airflow direction, and the inner wall of the guide zone 1011 is in the shape of a constricted trumpet or cone.

[0043] Furthermore, the transition zone 1013 is designed with a narrowing shape, which balances the airflow of the main air inlet 1012 with the airflow of the sub-air inlet 10111, preventing the airflow of the main air inlet 1012 from being too large, which would prevent the circumferential airflow from cutting into the sub-air inlet 10111. The transition zone 1013 guides the high-speed airflow entering from the main air inlet 1012 to be appropriately decelerated, the flow field tends to be uniform and stable, and it merges more smoothly with the circumferential airflow cutting into the sub-air inlet 10111 of the guide zone 1011, creating good initial conditions for the subsequent formation of efficient multi-stage shear in the guide zone 1011.

[0044] In one embodiment, refer to Figure 1 and Figure 2 The pipe body 1 is also provided with a mixing section 102. One end of the mixing section 102 is provided with an air outlet 1021, and the other end is connected to the guide zone 1011. The mixing section 102 and the guide zone 1011 are at least partially set at an angle.

[0045] In this embodiment, the pipe body 1 further includes a mixing section 102. The mixing section 102 is a bent pipe, one end of which serves as the outlet of the evaporation pipe, and the other end is connected to the end of the atomizing section 101, so that the axis of the mixing section 102 and the axis of the atomizing section 101 form an angle.

[0046] In one embodiment, the temperature of the mixing section 102 is higher than the temperature of the atomizing section 101.

[0047] It should be noted that the mixing section 102 is installed inside the flame tube 4. Under operating conditions, the wall of the mixing section 102 is heated, making its temperature higher than that of the atomizing section 101.

[0048] Furthermore, after the oil-gas mixture formed by the atomization section 101 is fully broken down, it enters the bent mixing section 102. Some of the oil droplets that are not fully atomized will hit the pipe wall again due to inertia and be broken down further. At the same time, since the mixing section 102 is inserted into the flame tube 4, its pipe wall is heated by the high-temperature gas, causing the oil mist flowing in it to evaporate rapidly into a uniform oil-gas mixture.

[0049] In one embodiment, refer to Figures 1 to 3 The oil injection section 201 extends along the axial direction of the atomizing section 101 into the transition zone 1013. The oil injection section 201 is provided with at least one oil injection port 202, and the axial direction of the oil injection port 202 is set at an angle to the axial direction of the atomizing section 101.

[0050] In this embodiment, the fuel injection section 201 of the fuel supply pipe 2 extends axially along the atomizing section 101 and passes through the main air intake 1012, with its end at least partially located within the transition zone 1013. At least one fuel injection port 202 is provided on the end wall of the fuel injection section 201. The axial direction of the fuel injection port 202 is set at an acute angle to the axial direction of the atomizing section 101, so that the fuel ejected from the fuel injection port 202 obliquely impacts the inner surface of the transition zone 1013 or downstream of the pipe wall, achieving initial wall breakage and forming an oil film that moves along the guide zone 1011 along the wall surface, preparing for subsequent multi-stage airflow shear atomization.

[0051] In this embodiment, four fuel injectors 202 are provided.

[0052] According to an embodiment of the present invention, in a second aspect, referring to Figures 4 to 6 The invention also provides a combustion chamber, comprising: a casing 3, a flame tube 4, and an evaporator oil supply device as described in the first aspect; the casing 3 includes an outer casing 301 and an inner casing 302, which are coaxially arranged and connected to each other, forming an annular airflow channel 5 between them; the flame tube 4 is disposed in the airflow channel 5 and connected to the casing 3; the pipe body 1 of the evaporator oil supply device is installed on the flame tube 4, and the mixing section 102 extends into the interior of the flame tube 4.

[0053] In this embodiment, the combustion chamber includes a casing 3, a flame tube 4, and an evaporator oil supply device. The casing 3 includes an outer casing 301 and an inner casing 302 that are coaxially fitted and fixedly connected, forming an annular airflow channel 5 between them. The flame tube 4 is installed in the airflow channel 5, and the mixing section 102 of the evaporator tube is bent and penetrates the outer ring of the flame tube 4, extending into the high-temperature region inside the flame tube 4. Furthermore, during operation, after the airflow is split through the annular channel, a portion enters the evaporator oil supply device to participate in atomization and mixing. The resulting uniform premixed gas is injected into the main combustion zone from the oblique outlet and ignited, achieving stable and efficient combustion.

[0054] It should be noted that the combustion chamber is also equipped with an inlet, at which a compressor or diffuser is installed. The compressor compresses the air and then passes it into the passage.

[0055] In one embodiment, refer to Figure 5 The flame tube 4 is equipped with multiple evaporator oil supply devices, which are distributed at intervals around the flame tube 4. The oil supply pipe 2 of each evaporator oil supply device is connected to the casing 3.

[0056] In this embodiment, multiple evaporator oil supply devices, such as those in the first aspect, are evenly installed circumferentially on the flame tube 4 to achieve uniform oil supply; the oil supply pipe 2 of each evaporator oil supply device is fixed on the combustion chamber casing 3 and connected to the fuel main pipe to form a stable fuel supply path.

[0057] Furthermore, the fuel supply pipe 2 is fixed inside the combustion chamber casing 3 and does not contact the pipe body 1, which makes the airflow into the main air intake 1012 smoother and reduces the impact on the airflow direction. This prevents the airflow in the main air intake 1012 from being blocked by the fuel supply pipe 2 and flowing only in one direction, resulting in poor fuel atomization.

[0058] In one embodiment, refer to Figure 4 The flame tube 4 is provided with a combustion zone 401, the mixing section 102 is a bent pipe section, and the air outlet 1021 is axially oriented toward the combustion zone 401.

[0059] In this embodiment, the mixing section 102 of the evaporator oil supply device is constructed as a bent pipe. This bent pipe section tilts its outlet axially and precisely points to the combustion zone 401 inside the flame tube 4 where the temperature is highest. Through this design, the high-speed, uniformly premixed gas ejected from the outlet can directly enter the core combustion region, utilizing the high-temperature environment of this region to further promote complete combustion, thereby improving combustion stability and efficiency.

[0060] Furthermore, the outlet is positioned towards the combustion zone 401, causing the ejected gas to collide with the inner wall of the flame tube 4, resulting in entrainment and deceleration, reducing the flow velocity in the combustion zone 401, and improving combustion efficiency.

[0061] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An oil supply device for an evaporator tube, characterized in that, include: The tube body (1) includes an atomizing section (101), which is provided with a main air inlet (1012) and a plurality of sub-air inlets (10111). The main air inlet (1012) is arranged along the axial direction of the atomizing section (101), and the plurality of sub-air inlets (10111) are arranged along the circumferential direction of the atomizing section (101). The airflow directions of the main air inlet (1012) and the sub-air inlets (10111) intersect. The oil supply pipe (2) includes an oil injection section (201) facing the main air inlet (1012) of the atomizing section (101).

2. The evaporator oil supply device according to claim 1, characterized in that, The atomizing section (101) is provided with a flow guiding area (1011), and the sub-inlet (10111) is located in the flow guiding area (1011). The flow guiding area (1011) is provided with a multi-stage flow guiding structure group (10112). The flow guiding structure group (10112) includes multiple flow guiding plates (10112-1). The flow guiding plates (10112-1) correspond one-to-one with the sub-inlet (10111). The flow guiding plates (10112-1) are set at an angle to the atomizing section (101) and face away from the main inlet (1012). The flow guiding plates (10112-1) partially cover the sub-inlet (10111).

3. The evaporator oil supply device according to claim 2, characterized in that, The flow guiding structure group (10112) is distributed at intervals along the axial direction of the flow guiding area (1011), and adjacent two-stage flow guiding structure groups (10112) are staggered in the circumferential direction. The angle between the flow guiding plate (10112-1) and the inner wall of the flow guiding area (1011) gradually increases along the airflow direction of the main air inlet (1012).

4. The evaporator tube oil supply device according to claim 2, characterized in that, The atomizing section (101) is further provided with a transition zone (1013), which connects the main air inlet (1012) and the guide zone (1011). The diameter of the transition zone (1013) increases from the main air inlet (1012) to the guide zone (1011).

5. The evaporator tube oil supply device according to claim 2, characterized in that, The pipe body (1) is also provided with a mixing section (102), one end of which is provided with an air outlet (1021), and the other end is connected to the guide zone (1011), and the mixing section (102) and the guide zone (1011) are at least partially set at an angle.

6. The evaporator tube oil supply device according to claim 5, characterized in that, The temperature of the mixing section (102) is higher than the temperature of the atomizing section (101).

7. The evaporator tube oil supply device according to claim 4, characterized in that, The oil spray section (201) extends along the axial direction of the atomizing section (101) into the transition zone (1013). The oil spray section (201) is provided with at least one oil spray port (202), and the axial direction of the oil spray port (202) is set at an angle to the axial direction of the atomizing section (101).

8. A combustion chamber, characterized in that, include: The casing (3) includes an outer casing (301) and an inner casing (302), which are coaxially arranged and connected to each other, forming an annular airflow channel (5) between them. The flame tube (4) is disposed in the airflow channel (5) and connected to the casing (3); The evaporator tube oil supply device according to any one of claims 1 to 7, wherein the tube body (1) is installed on the flame tube (4), and the mixing section (102) extends into the interior of the flame tube (4).

9. The combustion chamber according to claim 8, characterized in that, The flame tube (4) is provided with a plurality of evaporator oil supply devices, and the evaporator oil supply devices are distributed at intervals along the circumference of the flame tube (4), wherein the oil supply pipe (2) of each evaporator oil supply device is connected to the casing (3).

10. The combustion chamber according to claim 8, characterized in that, The flame tube (4) is provided with a combustion zone (401), the mixing section (102) is a bent pipe section, and the air outlet (1021) is axially oriented toward the combustion zone (401).

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