A modeling method for annular rotating single-tube flame tube

Abstract

The present invention discloses a modeling method for an annular-to-single-tube flame tube, which relates to the technical field of combustion chamber design, and is used to solve the problem that the prior art cannot simulate the combustion characteristics of an annular combustion chamber using a low-cost single-tube combustion chamber test. The technical key points of the present invention include: the annular flame tube is composed of N 1 / N period annular flame tubes with the same structure and combustion characteristics, and the process of modeling the 1 / N period annular flame tube into a single-tube flame tube includes: for the front section, the middle section contour line of the front section is rotated around the central axis of the circular port to form a bowl-shaped closed cycle, forming the front section of the single-tube flame tube; for the rear section, the contraction angle is reduced according to the profile line of the front section of the single-tube flame tube, so that the rear section contour line is smoothly connected with the front section profile line; and the outer ring contour line of the middle section of the rear section is rotated around the central axis of the circular port to form a cylindrical closed cycle, forming the rear section of the single-tube flame tube. The present invention makes the combustion characteristics of the single-tube flame tube similar to those of the annular flame tube through modeling.

Description

Technical Field

[0001] The invention relates to the technical field of combustion chamber design, and in particular to a modeling method for an annular to single-tube flame tube. Background Art

[0002] Gas turbine is a kind of thermal machinery used in the fields of shipbuilding, aviation and power generation, mainly including three major components: compressor, combustion chamber and turbine. The combustion chamber is responsible for converting the chemical energy contained in the fuel into high-temperature and high-pressure combustion products through combustion chemical reactions, which drives the turbine to do work. At present, the test of the combustion chamber of the gas turbine fueled by natural gas is divided into the following three steps: the first step is to test the single-head single-tube combustion chamber; the second step is to test the single-head annular combustion chamber; the third step is to test the multi-head annular combustion chamber. If the combustion characteristic indicators of the single-head single-tube combustion chamber test in the first step meet the standards, the second step of the single-head annular combustion chamber test will be carried out. The combustion chamber can be divided into three core components: swirler, flame tube and heat shield. The swirler and heat shield are universal in different steps, and only the quantity changes.

[0003] Since the annular combustion chamber test is very costly, in order to ensure that the test can be carried out effectively and steadily, it is worth studying how to utilize the low-cost single-tube combustion chamber test and obtain the results to improve the high-cost annular combustion chamber test. Summary of the invention

[0004] To this end, the present invention proposes a method for modeling an annular rotating single-tube flame tube in an effort to solve or at least alleviate at least one of the above problems.

[0005] A method for modeling an annular to single-tube flame tube, wherein the annular flame tube is composed of N 1 / N period annular flame tubes with the same structure and combustion characteristics, the 1 / N period annular flame tube is in a horizontal U shape, and is divided into a front section and a rear section, the front section is the lower part of the U shape, and the rear section is the upper part of the U shape; the U-shaped bottom, i.e., the head position of the front section, has a circular port for positioning and matching a swirler;

[0006] The modeling refers to: converting the annular flame tube into a single-tube flame tube, so that the combustion characteristics of the single-tube flame tube are similar to those of the annular flame tube; the process of modeling the annular flame tube into the single-tube flame tube includes:

[0007] For the front section of the 1 / N period annular flame tube, under the premise of ensuring that the profile line of the middle section of the front section remains unchanged and the diameter of the circular port remains unchanged, the profile line of the middle section of the front section rotates around the central axis of the circular port to form a bowl-shaped closed cycle, forming the front section of the single-tube flame tube;

[0008] For the rear section of the 1 / N period annular flame tube, under the premise of ensuring that the shape of the outer ring contour line of the middle section of the rear section remains unchanged, the contraction angle is reduced according to the profile of the front section of the single-tube flame tube, so that the contour line of the rear section is smoothly connected with the profile line of the front section of the single-tube flame tube; and the outer ring contour line of the middle section of the rear section is rotated around the central axis of the circular port to form a cylindrical closed period, forming the rear section of the single-tube flame tube.

[0009] Furthermore, an outlet transition section is added behind the rear section of the formed single-tube flame tube, and the outlet transition section uses a smooth transition profile to transition the circular outlet into an annular outlet.

[0010] Furthermore, the front section of the 1 / N period annular flame tube has three groups of front section cooling holes, one group of which surrounds the circular port, and the other two groups are evenly arranged in the expansion section, and the expansion section is the part connected to the head position of the front section; the process of modeling the annular flame tube into a single-tube flame tube also includes: the front section cooling holes of the front section of the single-tube flame tube are arranged as: three groups are evenly and concentrically arranged around the central axis of the circular port.

[0011] Furthermore, the rear section of the 1 / N period annular flame tube includes two upper and lower contracting transition sections, the transition section is composed of a support plate and film cooling holes, the film cooling holes are located between the support plate and the flame tube wall, and the number of film cooling holes on the upper and lower transition sections is not equal; the process of modeling the annular flame tube into a single-tube flame tube also includes: the arrangement of the film cooling holes in the rear section of the single-tube flame tube is: the same as the total area of ​​the film cooling holes of the 1 / N period annular flame tube, uniformly and concentrically arranged at equal intervals between the support plate and the flame tube wall.

[0012] Furthermore, the front section of the annular flame tube and the front section of the single-tube flame tube each account for 30% of the overall length, and the rear section of the annular flame tube and the rear section of the single-tube flame tube each account for 70% of the overall length.

[0013] Furthermore, the upper transition section of the rear section of the 1 / N period annular flame tube has 5 groups of film cooling holes, and the lower transition section has 4 groups of film cooling holes; the rear section of the single-tube flame tube has 4 groups of film cooling holes in a closed cycle.

[0014] Furthermore, the circular outlet and the annular outlet in the outlet transition section have the same outlet height and outlet area.

[0015] Furthermore, the modeling process of modeling the 1 / N period annular flame tube into a single-tube flame tube is realized by three-dimensional modeling software, and the three-dimensional modeling software includes UG software.

[0016] The beneficial technical effects of the present invention are:

[0017] The present invention provides a modeling method for annular-to-single-tube flame tube. By ensuring that the middle section contour lines and lengths of the front section of the flame tube before and after the modeling are the same, the single-tube flame tube test can reflect the combustion characteristics of the main combustion zone of the annular flame tube test; by ensuring that the middle section contour lines of the rear section of the flame tube before and after the modeling are the same and consistent with the slope of the front section profile, the resistance loss of the single-tube flame tube test is small, and the flow field distribution of the annular flame tube test can be reflected; by adding an outlet transition section, the same height and total area of ​​the flame tube outlet before and after the modeling are ensured, so that the single-tube flame tube test can reflect the outlet temperature distribution of the annular flame tube test; by ensuring that the cooling methods and total cooling areas before and after the modeling are the same, the single-tube flame tube test can reflect the wall temperature distribution of the annular flame tube test. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, in which:

[0019] Figure 1 It is a schematic flow chart of a method for modeling an annular to single-tube flame tube according to an embodiment of the present invention.

[0020] Figure 2 1 is a structural diagram of an annular flame tube that needs to be modeled in an embodiment of the present invention; wherein (a) corresponds to a complete cycle; and (b) corresponds to 1 / 20 cycle.

[0021] Figure 3 It is the front view of the 1 / 20 period annular flame tube modeled as a single-tube flame tube in an embodiment of the present invention.

[0022] Figure 4 It is a mid-section view of a 1 / 20 period annular flame tube modeled as a single-tube flame tube in an embodiment of the present invention.

[0023] Figure 5 It is a front view of the front section of the 1 / 20 period annular flame tube in an embodiment of the present invention, which is modeled as the front section of a single-tube flame tube.

[0024] Figure 6 It is a mid-section view of the front section of the 1 / 20 period annular flame tube in an embodiment of the present invention, which is modeled as the front section of a single-tube flame tube.

[0025] Figure 7 It is a front view of the rear section of the 1 / 20 period annular flame tube in an embodiment of the present invention, which is modeled as the rear section of a single-tube flame tube.

[0026] Figure 8 It is a mid-section view of the rear section of the 1 / 20 period annular flame tube in an embodiment of the present invention modeled as the rear section of a single-tube flame tube.

[0027] Fig. 9 It is a schematic diagram of the shape of the rear section outlet of a 1 / 20 period annular flame tube in an embodiment of the present invention being modeled as the shape of the rear section outlet of a single-tube flame tube, wherein h is the height of the flame tube outlet.

[0028] Fig.10 Schematic diagram of a single-tube flame tube outlet transition section in an embodiment of the present invention; wherein (a) corresponds to a three-dimensional structural diagram; (b) corresponds to a half-section diagram, in which h is the flame tube outlet height. DETAILED DESCRIPTION

[0029] The principles and spirit of the present invention will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are provided only to enable those skilled in the art to better understand and implement the present invention, and are not intended to limit the scope of the present invention in any way. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0030] The present invention proposes a method for modeling an annular flame tube into a single-tube flame tube. Through modeling, the combustion characteristics of the single-tube flame tube are made similar to those of the annular flame tube. Therefore, a relatively simple single-tube flame tube test can be used to reflect the combustion characteristics, wall temperature characteristics and outlet temperature characteristics of the annular flame tube, and on this basis, the flame tube is improved and designed.

[0031] like Figure 1 As shown, a molding method of an annular to single-tube flame tube includes: molding of the front section of the annular flame tube, molding of the rear section of the annular flame tube, molding of the cooling holes of the front section of the annular flame tube, molding of the air film cooling holes of the rear section of the annular flame tube and molding of the outlet shape of the annular flame tube.

[0032] The modeling refers to converting the annular flame tube into a single-tube flame tube so that the combustion characteristics of the single-tube flame tube are similar to those of the annular flame tube.

[0033] The annular flame tube is composed of N 1 / N period annular flame tubes with the same structure and combustion characteristics. The 1 / N period annular flame tube is in a horizontal U shape and is divided into a front section 11 and a rear section 12. The front section 11 is the lower part of the U shape, and the rear section 12 is the upper part of the U shape. The U-shaped bottom, i.e., the head position of the front section 11, has a circular port 111 for positioning and matching the swirler.

[0034] For the 1 / N period annular flame tube front section 11, under the premise of ensuring that the cross-sectional contour line in the front section 11 remains unchanged and the diameter of the circular port 111 remains unchanged, the cross-sectional contour line in the front section 11 is rotated around the central axis of the circular port 111 to form a bowl-shaped closed cycle, forming a single-tube flame tube front section 21;

[0035] For the 1 / N period annular flame tube rear section 12, under the premise of ensuring that the shape of the outer ring contour line of the middle section of the rear section 12 remains unchanged, the contraction angle is reduced according to the profile line of the front section 21 of the single-tube flame tube, so that the contour line of the rear section 12 is smoothly connected with the profile line of the front section 21 of the single-tube flame tube; and the outer ring contour line of the middle section of the rear section 12 is rotated around the central axis of the circular port 111 to form a cylindrical closed cycle, forming the single-tube flame tube rear section 22;

[0036] An outlet transition section 25 is added behind the formed single-tube flame tube rear section 22, and the outlet transition section 25 uses a smooth transition profile to transition the circular outlet into an annular outlet.

[0037] Preferably, the front section 11 of the 1 / N period annular flame tube has three groups of front section cooling holes 13, one group of which surrounds the circular port 111, and the other two groups are evenly arranged in the expansion section 112, and the expansion section 112 is the part connected to the head position of the front section 11; the process of modeling the annular flame tube into a single-tube flame tube also includes: the front section cooling holes 23 of the front section 21 of the single-tube flame tube are arranged as: three groups are evenly and concentrically arranged around the central axis of the circular port 111.

[0038] Preferably, the 1 / N period annular flame tube rear section 12 includes two upper and lower contracting transition sections, the transition section is composed of a support plate 121 and air film cooling holes 14, the air film cooling holes 14 are located between the support plate 121 and the flame tube wall, and the number of air film cooling holes 14 on the upper and lower transition sections is not equal; the process of modeling the annular flame tube into a single-tube flame tube also includes: the air film cooling holes 24 of the single-tube flame tube rear section 22 are arranged as follows: the total area of ​​the air film cooling holes 14 of the 1 / N period annular flame tube rear section 12 is the same, and they are uniformly, concentrically and equidistantly arranged between the support plate 221 of the single-tube flame tube rear section 22 and the flame tube wall.

[0039] Preferably, the annular flame tube front section 11 and the single-tube flame tube front section 21 each account for 30% of their overall length, and the annular flame tube rear section 12 and the single-tube flame tube rear section 22 each account for 70% of their overall length.

[0040] Preferably, the upper transition section of the rear section 12 of the 1 / N period annular flame tube has 5 groups of film cooling holes 14, and the lower transition section has 4 groups of film cooling holes 14; the rear section 22 of the single-tube flame tube has 4 groups of film cooling holes 24 in a closed cycle.

[0041] Preferably, the circular outlet and the annular outlet in the outlet transition section 25 have the same outlet height and outlet area.

[0042] The present invention realizes the modeling process of modeling a 1 / N period annular flame tube into a single-tube flame tube through three-dimensional modeling software. The three-dimensional modeling software includes UG software, and can also be AutoCAD, Soildworks and other software. Specific embodiment 1

[0044] like Figure 2 As shown, a complete annular flame tube (see Figure (a)) is composed of N identical 1 / N period annular flame tubes (see Figure (b)), which are annular as a whole and have an outer ring and an inner ring. N is, for example, 20.

[0045] like Figure 3 and Figure 4 As shown in the left figure, the annular flame tube of the 1 / N period comprises: an annular flame tube front section 11, an annular flame tube rear section 12, annular front section cooling holes 13 and annular rear section film cooling holes 14, wherein the annular flame tube front section 11 and the annular flame tube rear section 12 are an integrated structure. As an example, the annular flame tube front section 11 accounts for 30% of the overall length, and the annular flame tube rear section 12 accounts for 70% of the overall length. A circular port 111 is arranged at the head of the front section 11 of the annular flame tube for positioning and matching the swirler; the part connected to the head position of the front section is the expansion section 112; the front section 11 has three groups of front section cooling holes 13, one group of which surrounds the circular port 111, and the other two groups are evenly arranged in the expansion section 112; the rear section 12 includes two upper and lower contraction-shaped transition sections, the transition section consists of a support plate 121 and an air film cooling hole 14, the air film cooling hole 14 is located between the support plate 121 and the flame tube wall, the number of air film cooling holes 14 on the upper and lower transition sections is not equal, and the air film cooling holes 14 are arranged evenly and evenly spaced, with 5 groups in the outer ring and 4 groups in the inner ring; the support plate 121 is located under the flame tube wall, and is unevenly distributed in rows according to the position of the high-temperature area. The function is to form a gap between the support plate and the adjacent flame tube wall, which can ensure that the air film cooling hole can form a larger area of ​​air film and better reduce the local thermal stress of the flame tube.

[0046] like Figure 3 and Figure 4 As shown in the right figure, the single-tube flame tube is cylindrical, and its components include: a single-tube flame tube front section 21, a single-tube flame tube rear section 22, a single-tube flame tube front section cooling hole 23, a single-tube rear section air film cooling hole 24 and a single-tube flame tube outlet transition section 25. The single-tube flame tube front section 21 and the single-tube flame tube rear section 22 are an integrated structure, the single-tube flame tube front section 21 is provided with a single-tube front section cooling hole 23, and the head of the single-tube flame tube front section 21 is provided with a circular port 211 for positioning and matching the swirler; the single-tube flame tube rear section 22 is provided with a single-tube rear section air film cooling hole 24, which is located between the support plate 221 of the single-tube flame tube and the flame tube wall.

[0047] In this embodiment, the method for modeling the front section of the annular flame tube is as follows: the front section of the annular flame tube 11 and the front section of the single-tube flame tube 21 both account for 30% of the total length of the flame tube. Since the main combustion zone of the combustion chamber, that is, the place where the most intense combustion reaction occurs mainly in the front section of the flame tube, in order to ensure that the combustion characteristics of the annular flame tube can be modeled, the middle section contour line of the front section of the annular flame tube 11 (see Figure 5 The dotted line frame in the left figure) and the middle section outline of the front section 21 of the single-tube flame tube (see Figure 5 The dotted line frame in the right figure is the same, so that the middle section contour line rotates around the central axis of the circular port 111 of the annular flame tube front section 11 to form a closed cycle, forming a single-tube flame tube front section 21, which guarantees the combustion characteristics of the main combustion zone to the greatest extent. At the same time, in order to match the same swirler, the diameters of the circular port 111 of the annular flame tube and the circular port 211 of the single-tube flame tube are the same. Figure 6 It is a mid-section view of the front section of the 1 / 20 period annular flame tube in an embodiment of the present invention, which is modeled as the front section of a single-tube flame tube.

[0048] In this embodiment, the modeling method of the rear section of the annular flame tube is as follows: to ensure that the combustion characteristics of the rear section are the same, first obtain the outer ring contour line shape of the middle section of the rear section 12 of the annular flame tube (see Figure 7 On the premise of ensuring that the shape of the single-tube flame tube profile remains unchanged, according to the profile of the front section 21 of the single-tube flame tube (see Figure 7 The dotted box in the right figure) adjusts the angle, that is, reduces the contraction angle, for example, the contraction angle is reduced from 18° to 12°, so as to make a smooth transition; then rotates around the central axis of the circular port 211 of the single-tube flame tube to form a closed cycle, that is, to form the single-tube flame tube rear section 22. The annular flame tube rear section 12 corresponds to the single-tube flame tube rear section 22, and the contour line of the modeled single-tube flame tube rear section 22 is made as consistent as possible with the contour line of the annular flame tube rear section 12 while ensuring that the corresponding outlet areas are the same; and the single-tube flame tube rear section 22 adopts the same gradually contracting form as the upper side of the annular flame tube rear section 12 to ensure the combustion characteristics. Figure 8 It is a mid-section view of the rear section of the 1 / 20 period annular flame tube in an embodiment of the present invention modeled as the rear section of a single-tube flame tube.

[0049] In this embodiment, the method for modeling the cooling holes of the front section of the annular flame tube is as follows: to ensure that the wall temperature characteristics of the front section of the single-tube flame tube 21 obtained by modeling are the same as those of the front section of the annular flame tube 11, and to ensure that the total area of ​​the cooling holes is the same, three rows are uniformly and concentrically arranged around the central axis of the circular port 211. The front section of the single-tube flame tube 21 adopts the same cooling method as the front section of the annular flame tube 11, and the number of the single-tube front section cooling holes 23 adopted by it is the same as that of the annular front section cooling holes 13, and they are uniformly and concentrically arranged.

[0050] In this embodiment, the method for modeling the film cooling holes of the rear section of the annular flame tube is as follows: to ensure that the wall temperature characteristics of the rear section 22 of the single-tube flame tube obtained by modeling are the same as those of the rear section 12 of the annular flame tube, the same film cooling method is adopted to ensure that the total area of ​​the cooling holes is the same, and the holes are evenly and evenly arranged between the support plate 221 and the wall of the flame tube, that is, 4 groups are closed. The rear section 22 of the single-tube flame tube adopts the same cooling method as the rear section 12 of the original annular flame tube, and the number of the single-tube rear section film cooling holes 24 adopted is the same as that of the annular rear section film cooling holes 14, and they are evenly arranged concentrically.

[0051] In this embodiment, Fig. 9 and Fig.10 As shown, the method for modeling the shape of the annular flame tube outlet is as follows: in order to ensure that the temperature distribution characteristics of the single-tube flame tube outlet obtained by modeling are the same as those of the original annular flame tube, the outlet area must be the same and the shape must be similar. Since the outlet shape of the single-tube flame tube rear section 22 obtained by rotation is circular, while the outlet shape of the annular flame tube rear section 12 is annular, a single-tube flame tube outlet transition section 25 is added to the rear of the single-tube flame tube rear section 22, and a smooth transition profile is used to ensure that the outlet height h remains unchanged and the outlet area is the same, and the single-tube flame tube outlet transition section 25 is obtained.

[0052] Although the spirit and principles of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the specific embodiments disclosed, and the division into various aspects does not mean that the features in these aspects cannot be combined to benefit. The present invention is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the appended claims.

Claims

1. A method for modeling an annular to single-tube flame tube, characterized in that: The annular flame tube is composed of N 1 / N period annular flame tubes with the same structure and combustion characteristics. The 1 / N period annular flame tube is in a horizontal U shape and is divided into an annular flame tube front section (11) and an annular flame tube rear section (12). The annular flame tube front section (11) is the lower part of the U shape, and the annular flame tube rear section (12) is the upper part of the U shape. The U-shaped bottom, i.e., the head position of the annular flame tube front section (11), is provided with a circular port (111) for positioning and matching the swirler. The modeling refers to: converting the annular flame tube into a single-tube flame tube, so that the combustion characteristics of the single-tube flame tube are similar to those of the annular flame tube; the process of modeling the annular flame tube into the single-tube flame tube includes: For the 1 / N period annular flame tube front section (11), under the premise of ensuring that the cross-sectional contour line of the annular flame tube front section (11) remains unchanged and the diameter of the circular port (111) remains unchanged, the cross-sectional contour line of the annular flame tube front section (11) is rotated around the central axis of the circular port (111) to form a bowl-shaped closed cycle, thereby forming a single-tube flame tube front section (21); For the 1 / N period annular flame tube rear section (12), under the premise of ensuring that the shape of the outer ring contour line of the middle section of the annular flame tube rear section (12) remains unchanged, the contraction angle is reduced according to the profile of the single-tube flame tube front section (21), so that the contour line of the annular flame tube rear section (12) is smoothly connected with the profile line of the single-tube flame tube front section (21); and the outer ring contour line of the middle section of the annular flame tube rear section (12) is rotated around the central axis of the circular port (111) to form a cylindrical closed period, thereby forming the single-tube flame tube rear section (22).

2. The molding method of an annular to single-tube flame tube according to claim 1, characterized in that: An outlet transition section (25) is added behind the formed single-tube flame tube rear section (22), and the outlet transition section (25) uses a smooth transition profile to transition the circular outlet into an annular outlet.

3. A method for molding an annular to single-tube flame tube according to claim 1 or 2, characterized in that: The 1 / N period annular flame tube front section (11) has three groups of front section cooling holes (13), one of which surrounds the circular port (111), and the other two groups are evenly arranged in the expansion section (112), and the expansion section (112) is a part connected to the head position of the annular flame tube front section (11); the process of modeling the annular flame tube into a single-tube flame tube also includes: the front section cooling holes (23) of the single-tube flame tube front section (21) are arranged as follows: three groups are evenly and concentrically arranged around the central axis of the circular port (111).

4. A method for molding an annular to single-tube flame tube according to claim 1 or 2, characterized in that: The 1 / N period annular flame tube rear section (12) comprises an upper transition section and a lower transition section in a contracting shape, the upper transition section and the lower transition section both being composed of a support plate (121) and air film cooling holes (14), the air film cooling holes (14) of the upper transition section and the lower transition section being located between the support plate (121) and the flame tube wall, and the number of air film cooling holes (14) on the upper transition section and the lower transition section being unequal; The process of modeling the annular flame tube into a single-tube flame tube also includes: the air film cooling holes (24) of the rear section (22) of the single-tube flame tube are arranged to have the same total area as the air film cooling holes (14) of the rear section (12) of the 1 / N period annular flame tube, and are uniformly and concentrically arranged at equal intervals between the support plate (221) of the rear section (22) of the single-tube flame tube and the flame tube wall.

5. The molding method of an annular to single-tube flame tube according to claim 1 or 2, characterized in that: The annular flame tube front section (11) and the single-tube flame tube front section (21) each account for 30% of the overall length, and the annular flame tube rear section (12) and the single-tube flame tube rear section (22) each account for 70% of the overall length.

6. The molding method of an annular to single-tube flame tube according to claim 4, characterized in that: The film cooling holes (14) of the upper transition section of the rear section (12) of the 1 / N cycle annular flame tube are 5 groups, and the film cooling holes (14) of the lower transition section are 4 groups; the film cooling holes (24) of the rear section (22) of the single-tube flame tube are 4 groups of closed cycles.

7. The molding method of an annular to single-tube flame tube according to claim 2, characterized in that: The circular outlet and the annular outlet in the outlet transition section (25) have the same outlet height and outlet area.

8. The molding method of an annular to single-tube flame tube according to claim 1 or 2, characterized in that: The modeling process of modeling the 1 / N period annular flame tube into a single-tube flame tube is realized by three-dimensional modeling software, and the three-dimensional modeling software includes UG software.

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