A single-pipe combustion chamber outlet transition section design method and transition section

Abstract

This invention discloses a design method and transition section for the outlet of a single-tube combustor, relating to the field of combustor design technology. It addresses the problems of difficult early-stage modeling and later-stage modification caused by existing transition section designs utilizing multiple cross-sections for transition forming. Key technical points of this invention include: the outlet transition section comprises an inlet, a transition section body, and an outlet. The intersection line between the plane forming a 90° angle with the plane passing through the central axes of the inlet and outlet and the transition section body is defined as the left and right side profile lines. The intersection line between the plane forming a 0° angle with the plane passing through the central axes of the inlet and outlet and the transition section body is defined as the upper and lower side profile lines. The beginning of the upper and lower side profile lines is tangent to the curved surface at the outlet of the combustor flame tube, and the end is tangent to the axis. The beginning of the left and right side profile lines is tangent to the curved surface at the outlet of the combustor flame tube in the axial direction, and the end forms an acute angle with the axis of symmetry of the left and right side profile lines. In application, this invention can effectively reduce flow losses and mitigate the erosion of the turbine by high temperatures.

Description

Technical Field

[0001] This invention relates to the field of combustion chamber design technology, specifically to a design method and transition section for the outlet of a single-tube combustion chamber. Background Technology

[0002] The transition section of a gas turbine combustor is a component that guides the transition of the gas flow. It transforms the circular cross-section of the combustor outlet into a fan-shaped / rectangular cross-section in front of the turbine guide vanes. By changing the cross-sectional shape, the cross-sectional area of ​​the airflow channel converges to a certain extent to achieve the axial flow velocity required by the turbine inlet cross-section, thus rectifying the high-temperature gas flow at the rear of the gas turbine combustor. Therefore, the design of the transition section component must ensure that the cross-section of the component transitions as smoothly as possible from a fan shape to reduce flow resistance loss, and also ensure that the convergence rate of the cross-sectional area of ​​the component is appropriate to improve the uniformity of the outlet flow field. In the existing technology, the transition section of the gas turbine combustor is curved and often has problems such as poor smooth transition effect and flow resistance loss.

[0003] Studies on combustion chamber transition sections include: Chinese Patent No. 202120847351.1 discloses a transition section for a test gas turbine combustion chamber. The transition section body requires smooth transition from multiple cross sections during its forming process, increasing the difficulty of modeling in the numerical simulation process before the experiment. A large number of cross-sectional curves are needed to ensure a smooth transition, and adjustments to the direction, shape, and position of the transition section later are also difficult. Chinese Patent No. 201320548299.5 discloses a transition section structure for a gas turbine combustion chamber. Its transition section forming uses a cross-sectional shape change function, a centerline position function, and a cross-sectional inclination angle to determine the shape and position of the cross section, enabling precise control. However, its forming method still requires countless cross sections to achieve a smooth transition, does not use spline curves for transition, and later modifications are difficult. Summary of the Invention

[0004] Therefore, this invention proposes a design method and transition section for the outlet of a single-tube combustion chamber, in an attempt to solve or at least alleviate at least one of the problems mentioned above.

[0005] According to one aspect of the present invention, a design method for an outlet transition section of a single-tube combustion chamber is provided. The outlet transition section includes an inlet, a transition section body, and an outlet. The intersection line of a plane forming a 90° angle with the plane passing through the central axes of the inlet and outlet with the transition section body is defined as the left and right side profile lines. The intersection line of a plane forming a 0° angle with the plane passing through the central axes of the inlet and outlet with the transition section body is defined as the upper and lower side profile lines. The left and right side profile lines and the upper and lower side profile lines are all continuously differentiable nth-order spline curves, where n is an integer greater than or equal to 3.

[0006] The upper and lower side profile lines are designed according to the following method:

[0007] The beginning of the upper and lower side profile lines is tangent to the curved surface at the outlet of the combustion chamber flame tube, and the end is tangent to the axis, so as to achieve a smooth transition with the tail of the flame tube; the inflection point of the upper and lower side profile lines appears at 1 / 2 of the transition section body, and after the inlet reaches 3 / 4 of the transition section body, the absolute value of the slope of the spline curve is less than 0.5 and gradually decreases to 0;

[0008] The left and right side profile lines are designed according to the following method:

[0009] The beginning of the left and right side profile lines is tangent to the curved surface of the combustion chamber flame tube outlet in the axial direction, and the end of the profile lines forms an acute angle with the axis of symmetry of the left and right side profile lines; the extreme point of the left and right side profile lines appears at 1 / 2 of the transition section body, and the distance between the extreme point and the axis of symmetry of the left and right side profile lines is less than half of the outlet side length.

[0010] Furthermore, the left and right side profile lines are always symmetrical about the mid-section; when the inlet and outlet centers are located on the same horizontal line, the upper and lower side profile lines are symmetrically distributed.

[0011] Furthermore, the inlet is circular or elliptical in shape; the outlet is rectangular or fan-shaped with rounded corners.

[0012] Furthermore, the transition section body is provided with cooling structures, which are multi-slanted hole cooling or air film cooling.

[0013] Furthermore, the cooling holes of the cooling structure have a diameter of 0.5~1mm, are distributed in 4~6 rows along the axial direction, and are distributed in 60~100 rows along the circumferential direction of the cross section. The number of selected holes is divisible by 360, and the drilling direction is at 30°~35° with the tangential direction of the transition section body.

[0014] Furthermore, the design of the outlet transition section of the single-tube combustion chamber is realized through 3D modeling software, including UG software.

[0015] According to another aspect of the present invention, a single-tube combustion chamber outlet transition section is provided, the outlet transition section being designed according to the single-tube combustion chamber outlet transition section design method described above.

[0016] The beneficial technical effects of this invention are:

[0017] This invention provides a design method and transition section for the outlet of a single-tube combustor. The transition section is formed using only four profile lines and two closed-loop curves at the inlet and outlet, which is simpler and easier to adjust later compared to existing methods using multiple cross-sectional curves. The profile lines of this invention employ n-fold continuously differentiable spline curves to achieve a smooth transition, effectively reducing flow losses. Adjusting the shape and position of the spline curves can effectively improve the outlet temperature field distribution and reduce the erosion of the turbine inlet by the high-temperature combustion gas at the combustor outlet. This invention also enables the conversion of flame tube outlets of different sizes or shapes into fixed-size rectangular or fan-shaped outlets in single-tube combustor experiments, making the experimental results closer to those of a real annular combustor. Attached Figure Description

[0018] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of the invention are illustrated in the drawings by way of example and not limitation, wherein:

[0019] Figure 1 This is a flowchart illustrating the transition section design method according to an embodiment of the present invention.

[0020] Figure 2 (a) is a schematic diagram of the transition section with the inlet and outlet on the same horizontal line in the embodiment of the present invention; (b) is a schematic diagram of the structure and position of the transition section; (c) is a schematic diagram of the inflection point position of the upper and lower side profile lines; and (d) is a schematic diagram of the extreme point position of the left and right side profile lines.

[0021] Figure 3 (a) is a schematic diagram of the transition section inlet and outlet on different horizontal lines in the embodiment of the present invention; (b) is a schematic diagram of the structure and position of the transition section; (c) is a schematic diagram of the inflection point position of the upper and lower side profile lines; and (d) is a schematic diagram of the extreme point position of the left and right side profile lines. Detailed Implementation

[0022] The principles and spirit of the invention will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are given merely to enable those skilled in the art to better understand and implement the invention, and are not intended to limit the scope of the invention in any way. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of this disclosure to those skilled in the art.

[0023] This invention provides a design method for the outlet transition section of a single-tube combustion chamber. The outlet transition section includes an inlet, a transition section body, and an outlet. The intersection line of the plane forming a 90° angle with the plane passing through the central axes of the inlet and outlet with the transition section body is defined as the left and right side profile lines. The intersection line of the plane forming a 0° angle with the plane passing through the central axes of the inlet and outlet with the transition section body is defined as the upper and lower side profile lines. The left and right side profile lines and the upper and lower side profile lines are all continuously differentiable nth-order spline curves, where n is an integer greater than or equal to 3.

[0024] 1) The upper and lower side profile lines are designed according to the following method:

[0025] The beginning of the upper and lower side profile lines is tangent to the curved surface at the outlet of the combustion chamber flame tube, and the end is tangent to the axis, so as to achieve a smooth transition with the tail of the flame tube; the inflection point of the upper and lower side profile lines appears at 1 / 2 of the transition section body, and after the inlet reaches 3 / 4 of the transition section body, the absolute value of the slope of the spline curve is less than 0.5 and gradually decreases to 0;

[0026] 2) The left and right side profile lines are designed according to the following method:

[0027] The beginning of the left and right side profile lines is tangent to the curved surface of the combustion chamber flame tube outlet in the axial direction, and the end of the profile lines forms an acute angle with the axis of symmetry of the left and right side profile lines. The extreme point of the left and right side profile lines appears at 1 / 2 of the transition section body, and the distance between the extreme point and the axis of symmetry of the left and right side profile lines is less than half of the outlet side length. As an example, the distance between the extreme point and the axis of symmetry of the left and right side profile lines is 20% to 40% of the corresponding outlet side length a.

[0028] In this embodiment, preferably, the left and right side profile lines are always symmetrical about the mid-section; when the inlet and outlet centers are located on the same horizontal line, the upper and lower side profile lines are symmetrically distributed.

[0029] In this embodiment, preferably, the shape of the inlet is circular or elliptical; the shape of the outlet is rectangular or fan-shaped with rounded corners.

[0030] In this embodiment, preferably, the transition section body is provided with a cooling structure, which is a multi-slanted hole cooling or a film cooling.

[0031] In this embodiment, preferably, the diameter of the cooling holes in the cooling structure is 0.5~1mm, distributed in 4~6 rows along the axial direction, and 60~100 holes distributed circumferentially along the cross-section. The number of selected holes is divisible by 360, and the drilling direction is at 30°~35° with the cross-sectional direction of the transition section body.

[0032] In this embodiment, preferably, the design of the single-tube combustion chamber outlet transition section is realized by three-dimensional modeling software, including UG software, and can also be AutoCAD, Solidworks, and other software. Specific Implementation Example 1

[0034] like Figure 1 As shown, a design method for the outlet transition section of a single-tube combustion chamber includes: inlet shape design, outlet shape design, inlet-outlet relative position design, left and right side profile design, upper and lower side profile design, and cooling structure design. The transition section is formed by using UG through a curved mesh.

[0035] like Figure 2 or Figure 3 As shown, the combustion chamber flame tube 1 is connected to the outlet transition section 2, which includes an inlet 21, a transition section body 22, and an outlet 23. The profile lines on the transition section body 22 are defined as the lines of intersection between the transition section and planes forming angles of 0° to 180° with the planes passing through the inlet and outlet center axes. In this embodiment, two planes differing by 90° from the transition section are selected as the lines of intersection with the transition section; that is, the lines of intersection at 90° are the left and right side profile lines 221, and the lines of intersection at 0° are the upper and lower side profile lines 222.

[0036] All profile lines are continuously differentiable nth-order spline curves (n is an integer greater than or equal to 3). (nth-order spline curve: a curve with multiple nodes connected by an nth-order interpolation function). Whether the inlet and outlet centers are on the same horizontal line or not, the left and right profile lines 221 are always symmetrical about the mid-section. Figure 2 As shown, when the centers of the inlet and outlet are on the same horizontal line, the upper and lower side profile lines 222 are symmetrically distributed; as Figure 3 As shown, when the import and export centers are not on the same horizontal line, the upper and lower side surface lines 222 are asymmetrically distributed.

[0037] Specifically, a single-tube combustion chamber outlet transition section can be designed as follows:

[0038] 1. The imported shape is designed to be either circular or oval, and smoothly connects to the tail of the flame tube;

[0039] 2. The outlet shape design can be rectangular or sector-shaped, with rounded corners and a corner radius less than 1 / 2 of the shorter side length of the outlet;

[0040] 3. The relative positions of import and export are designed such that the export center and the import center can be located on the same horizontal line or on different horizontal lines.

[0041] 4. The left and right side profiles are designed as follows: the beginning of the left and right side profiles is tangent to the curved surface at the outlet of the flame tube 1 in the axial direction, and the end forms an acute angle with the axis of symmetry of the left and right side profiles, for example, 30°~45°. The extreme points of the left and right side profiles appear at the 1 / 2 of the transition section, and the distance h between the extreme point and the axis of symmetry accounts for 20%~40% of the corresponding outlet side length a, which is intended to simulate the flow space of cooling air between the transition sections of each single tube in the annular combustion chamber.

[0042] 5. The upper and lower side profile lines are designed such that the beginning of the upper and lower side profile lines is always tangent to the curved surface at the outlet end of the flame tube 1 in the axial direction, and the end is tangent to the axis, so as to achieve a smooth transition with the tail of the flame tube. The inflection point of the upper and lower side profile lines appears at 1 / 2 of the transition section. After 3 / 4 of the transition section, the absolute value of the slope of the spline curve is less than 0.5 and gradually decreases to 0.

[0043] 6. The cooling structure is designed as either multi-slanted hole cooling or film cooling. Specifically, the diameter of the cooling holes in the cooling structure is 0.5~1mm, distributed in 4~6 rows along the axial direction, and 60~100 holes distributed circumferentially along the cross-section. The selected number of holes is divisible by 360, and the drilling direction is at an angle of 30°~35° to the tangential direction of the transition section.

[0044] Another embodiment of the present invention also proposes a single-tube combustion chamber outlet transition section, wherein the outlet transition section is designed according to the single-tube combustion chamber outlet transition section design method described above.

[0045] Although the operations of the method of the invention are described in a specific order in the accompanying drawings, this does not require or imply that the operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0046] While the spirit and principles of the invention have been described with reference to several specific embodiments, it should be understood that the invention is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for ease of description. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A design method for a single-tube combustion chamber outlet transition section, wherein the outlet transition section includes an inlet, a transition section body, and an outlet, characterized in that: The intersection line between the plane that forms a 90° angle with the plane passing through the central axis of the inlet and outlet and the body of the transition section is defined as the left and right side profile lines. The intersection line between the plane that forms a 0° angle with the plane passing through the central axis of the inlet and outlet and the body of the transition section is defined as the upper and lower side profile lines. The left and right side profile lines and the upper and lower side profile lines are both continuously differentiable nth-degree spline curves, where n is an integer greater than or equal to 3. The upper and lower side profile lines are designed according to the following method: The upper and lower side profile lines begin tangent to the curved surface at the outlet of the combustion chamber flame tube and end tangent to the axis, thus achieving a smooth transition with the tail of the flame tube; the inflection point of the upper and lower side profile lines appears at 1 / 2 of the transition section body, and after the transition section body reaches 3 / 4 of the position from the inlet, the absolute value of the slope of the spline curve is less than 0.5 and gradually decreases to 0; wherein, when the inlet and outlet centers are located on the same horizontal line, the upper and lower side profile lines are symmetrically distributed; The left and right side profile lines are designed according to the following method: The beginning of the left and right side profile lines is tangent to the curved surface of the combustion chamber flame tube outlet in the axial direction, and the end of the profile lines forms an acute angle with the axis of symmetry of the left and right side profile lines; the extreme point of the left and right side profile lines appears at 1 / 2 of the transition section body, and the distance between the extreme point and the axis of symmetry of the left and right side profile lines is less than half the length of the outlet side; wherein, the left and right side profile lines are always symmetrical about the mid-section.

2. The design method for the outlet transition section of a single-tube combustion chamber according to claim 1, characterized in that: The inlet is circular or elliptical in shape; the outlet is rectangular or fan-shaped with rounded corners.

3. The design method for the outlet transition section of a single-tube combustion chamber according to claim 1, characterized in that: The transition section body is provided with cooling structures, which are either multi-slanted hole cooling or air film cooling.

4. The design method for the outlet transition section of a single-tube combustion chamber according to claim 3, characterized in that: The cooling holes of the cooling structure have a diameter of 0.5~1mm, are distributed in 4~6 rows along the axial direction, and 60~100 holes are distributed circumferentially along the cross-section. The number of selected holes is divisible by 360, and the drilling direction is at 30°~35° with the cross-sectional direction of the transition section body.

5. A design method for the outlet transition section of a single-tube combustion chamber according to any one of claims 1-4, characterized in that: The design of the outlet transition section of the single-tube combustion chamber is realized through 3D modeling software, including UG software.

6. A transition section at the outlet of a single-tube combustion chamber, characterized in that: The outlet transition section is designed according to the single-tube combustion chamber outlet transition section design method according to any one of claims 1-5.

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