A method and system for processing boundary conditions of a re-ignition combustion chamber inlet

Abstract

The present invention discloses a method and system for processing boundary conditions of a re-ignition combustion chamber inlet, which relates to the technical field of combustion chamber design and is used to solve the problem that the flow field at the compressor outlet is distorted and the uneven parameter distribution mapped to the combustion chamber inlet after the action of the combustion cylinder affects the accuracy of the numerical simulation of the combustion chamber. The technical points of the present invention include: determining the corresponding combustion cylinder inlet and outlet boundary conditions for different combustion cylinder inlet intake forms; inputting the combustion cylinder inlet and outlet boundary conditions into the numerical simulation software for numerical simulation to obtain the corresponding combustion chamber inlet velocity distribution; performing polynomial fitting on the combustion chamber inlet velocity distribution to obtain the combustion chamber inlet boundary conditions; and further correcting the combustion chamber inlet boundary conditions according to the combustion chamber inlet mass flow rate. The present invention fully considers the impact of changes in the compressor outlet parameters on the combustion chamber, is closer to the actual operation of the gas turbine as a whole, and improves the accuracy of numerical simulation.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion chamber design, and in particular to a method and system for processing boundary conditions of a re-ignition combustion chamber inlet. Background Art

[0002] Heavy-duty gas turbines are widely used in power generation due to their high power density, excellent maneuverability, low vibration and noise, and high combined cycle efficiency. As a core component of heavy-duty gas turbines, the design and reliability of the gas turbine combustor are crucial to its proper operation. Therefore, combustor design must ensure that multiple indicators, including efficiency, flame stability, reliability, and emissions, meet design requirements across a wide range of operating conditions. This is a complex and challenging task.

[0003] The governing equations for flow and combustion within a combustion chamber are extremely complex. Classical combustion theory can only explain simple combustion processes, but cannot account for the coupled multi-physics processes of heat, flow, and chemical reactions involved in the actual operation of a combustion chamber, including gas flow, fuel atomization and evaporation, mixing, and cracking combustion. Consequently, the design of gas turbine combustors has long relied on empirical data, resulting in long development cycles and significant human and material resources. There is an urgent need to find an efficient and practical approach to combustor design. Numerical simulation, due to its many advantages, including limited limitations, short development cycles, and improved cost-effectiveness, has become a widely used and important method in combustor design and development.

[0004] Traditional numerical simulations of combustion chambers use uniform inlet boundary conditions, which ignore the impact of uneven flow field parameter distribution at the compressor outlet and the changes in flow parameters after the flow passes through the combustion and compression cylinder on combustion chamber performance, resulting in a series of errors. With the development of heavy-duty gas turbines, the continuous improvement of design levels and numerical simulation capabilities, the inlet and outlet conditions of combustion chamber simulations no longer set simple uniform inlet flow and "obstruction-free" outlets. Instead, they fully consider the impact of the actual outlet flow conditions of the upstream compressor on the combustion chamber performance, attempting to effectively solve the problem of large discrepancies between the simulated design performance of individual gas turbine components and the actual service performance of the entire unit.

[0005] Existing related research, for example: Chinese patent number CN202211234444.2 discloses a CFD-FEM joint simulation method for calculating the thermal insulation efficiency of an engine combustion chamber. Based on one-dimensional performance simulation, a three-dimensional model is established, and the boundary conditions of the one-dimensional calculation are input into the CFD calculation. The results are passed to the finite element model as boundary conditions to calculate the impact of insulation on the wall temperature and efficiency of the fuel engine; Chinese patent number CN201710462680.2 discloses a method for determining the closure of the boundary conditions of the rocket launch gas flow field, and provides a method to ensure that the inlet boundary parameters and physical parameters of the three-dimensional simulation of the launch gas dynamics meet the closure requirements, thereby greatly reducing the error between the simulation results and the test results, and improving the authenticity and reliability of the simulation results.

[0006] However, the above-mentioned existing methods do not take into account the uneven spatial distribution of inlet parameters when processing boundary conditions, resulting in distortion conditions at the inlet and errors when the parameters are uneven during numerical simulation. In particular, for the inlet of the heavy-duty gas turbine combustion chamber, there is distortion in the compressor outlet flow field, and the uneven parameter distribution mapped to the combustion chamber inlet after the action of the combustion cylinder will affect the accuracy of the numerical simulation of the combustion chamber. Summary of the Invention

[0007] To this end, the present invention proposes a method and system for processing boundary conditions at the inlet of a re-ignition combustion chamber, in an effort to solve or at least alleviate at least one of the above problems.

[0008] According to one aspect of the present invention, a method for processing boundary conditions of a re-ignition combustion chamber inlet is provided, the method comprising the following steps:

[0009] Step 1: For different fuel cylinder inlet intake forms, determine the corresponding fuel cylinder inlet and outlet boundary conditions;

[0010] Step 2: Input the boundary conditions of the combustion cylinder inlet and outlet into the numerical simulation software to perform numerical simulation and obtain the corresponding combustion chamber inlet velocity distribution;

[0011] Step 3: Perform polynomial fitting on the combustion chamber inlet velocity distribution to obtain the combustion chamber inlet boundary conditions.

[0012] Furthermore, it also includes step 4, inputting the combustion chamber inlet boundary conditions into numerical simulation software for calculation to obtain the combustion chamber inlet mass flow rate; correcting the combustion chamber inlet boundary conditions according to the combustion chamber inlet mass flow rate to correct the mass flow rate deviation caused by fitting, and using the corrected combustion chamber inlet velocity distribution as the final combustion chamber inlet boundary conditions.

[0013] Furthermore, the intake form of the combustion cylinder inlet in step one includes a uniform inlet form and a distorted inlet form; the inlet and outlet boundary conditions of the combustion cylinder include the inlet velocity, outlet pressure and operating pressure of the combustion cylinder.

[0014] Furthermore, the distorted inlet forms in step 1 include radial distortion, circumferential distortion, radial-circumferential coupled distortion and unsteady pulsation.

[0015] Furthermore, the combustion chamber inlet velocity distribution in step 2 is a set of distribution velocities on a circular surface with the center of the combustion chamber outlet as the origin and radial directions R1 and R2, where R2=Rmax, Rmax represents the maximum radius of the combustion chamber outlet cross section, and R1 <R2。

[0016] Furthermore, the specific process of step three includes: dividing the combustion chamber into multiple sections along the radial direction to form multiple segmented circular rings; taking half of the sum of the radii of any two adjacent circular rings as the radius to form a middle ring circle, and expanding the multiple middle ring circles along the circumferential direction to form multiple middle ring lines, and performing polynomial fitting on the velocity distribution of each middle ring line to obtain the combustion chamber inlet velocity distribution; wherein, the velocity distribution of each middle ring line is obtained based on the combustion chamber inlet velocity distribution.

[0017] Furthermore, the process of correcting the combustion chamber inlet boundary condition according to the combustion chamber inlet mass flow in step four includes: comparing the combustion chamber inlet mass flow simulation value calculated by numerical simulation software with the actual value of the combustion chamber inlet mass flow under real conditions; if the simulation value is higher than the actual value, reducing the distortion curve constant term coefficient corresponding to the distorted inlet form; if the simulation value is lower than the actual value, increasing the distortion curve constant term coefficient corresponding to the distorted inlet form; and taking the combustion chamber inlet velocity distribution corresponding to when the simulation value and the actual value are equal as the final combustion chamber inlet boundary condition.

[0018] According to another aspect of the present invention, a system for processing boundary conditions of a re-ignition combustion chamber inlet is provided, the system comprising:

[0019] An inlet velocity distribution acquisition module is configured to: determine corresponding combustion cylinder inlet and outlet boundary conditions for different combustion cylinder inlet intake forms; input the combustion cylinder inlet and outlet boundary conditions into numerical simulation software for numerical simulation to obtain corresponding combustion chamber inlet velocity distributions; the combustion cylinder inlet intake forms include uniform inlet forms and distorted inlet forms, and the distorted inlet forms include radial distortion, circumferential distortion, radial-circumferential coupled distortion, and unsteady pulsation; the combustion cylinder inlet and outlet boundary conditions include the combustion cylinder inlet velocity, outlet pressure, and operating pressure;

[0020] The inlet boundary condition acquisition module is configured to perform polynomial fitting on the combustion chamber inlet velocity distribution to obtain the combustion chamber inlet boundary condition.

[0021] Further, it further includes a correction module configured to: input the combustion chamber inlet boundary conditions into a numerical simulation software for calculation to obtain the mass flow rate at the combustion chamber inlet; correct the combustion chamber inlet boundary conditions according to the mass flow rate at the combustion chamber inlet to correct the mass flow rate deviation caused by fitting, and use the corrected velocity distribution at the combustion chamber inlet as the final combustion chamber inlet boundary conditions.

[0022] Further, the velocity distribution at the combustion chamber inlet is a set of velocity distributions on an annular surface with the center of the combustion chamber outlet as the origin and the radial directions as R1 and R2, where R2 = Rmax, Rmax represents the maximum radius of the outlet section of the combustion pressure cylinder, and R1 < R2; the process of performing polynomial fitting on the velocity distribution at the combustion chamber inlet includes: dividing the combustion chamber into multiple segments along the radial direction to form multiple segmented annuli; taking half of the sum of the radii of any two adjacent annuli as the radius to form a middle annulus circle, unfolding the multiple middle annulus circles along the circumferential direction to form multiple middle lines, and performing polynomial fitting on the velocity distribution of each middle line respectively to obtain the velocity distribution at the combustion chamber inlet; wherein, the velocity distribution of each middle line is obtained according to the velocity distribution at the combustion chamber inlet.

[0023] The beneficial technical effects of the present invention are:

[0024] The present invention provides a method and system for processing the inlet boundary conditions of a reheat combustion chamber, which is used for processing the inlet boundary conditions in the numerical simulation of a heavy-duty gas turbine combustion chamber. Compared with the traditional uniform inlet flow condition, the present invention fully considers the influence of the change of the compressor outlet parameters on the combustion chamber, is closer to the actual operating conditions of the entire gas turbine, and improves the numerical simulation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] By referring to the accompanying drawings and reading the following detailed description, the above and other objects, features, and advantages of the exemplary embodiments of the present invention will become easily understandable. In the drawings, several embodiments of the present invention are shown in an exemplary and non-restrictive manner, wherein:

[0026] Figure 1 is a flowchart of a method for processing the inlet boundary conditions of a reheat combustion chamber according to an embodiment of the present invention.

[0027] Figure 2 is a schematic diagram of the structural arrangement of a compressor, a combustion pressure cylinder, and a combustion chamber in an embodiment of the present invention.

[0028] Figure 3 is a contour map of the velocity distribution at the combustion chamber inlet under the uniform inlet flow condition at the compressor outlet obtained by numerical simulation in an embodiment of the present invention.

[0029] Figure 4This is a velocity distribution cloud diagram of the combustion chamber inlet obtained under the condition of uniform inlet flow at the combustion cylinder inlet in an embodiment of the present invention.

[0030] Figure 5 It is a velocity distribution cloud diagram under the condition of uniform combustion chamber inlet parameters in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] 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 solely 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. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0032] An embodiment of the present invention provides a method for processing boundary conditions of a heavy-duty gas turbine combustion chamber inlet, the method comprising the following steps:

[0033] Step 1: For different fuel cylinder inlet intake forms, determine the corresponding fuel cylinder inlet and outlet boundary conditions;

[0034] Step 2: Input the boundary conditions of the combustion cylinder inlet and outlet into the numerical simulation software to perform numerical simulation and obtain the corresponding combustion chamber inlet velocity distribution;

[0035] Step 3: Perform polynomial fitting on the combustion chamber inlet velocity distribution to obtain the combustion chamber inlet boundary conditions;

[0036] Step 4: Input the combustion chamber inlet boundary conditions into the numerical simulation software for calculation to obtain the combustion chamber inlet mass flow rate; modify the combustion chamber inlet boundary conditions according to the combustion chamber inlet mass flow rate to correct the mass flow rate deviation caused by fitting, and use the modified combustion chamber inlet velocity distribution as the final combustion chamber inlet boundary conditions.

[0037] In the embodiment of the present invention, the combustion chamber inlet boundary condition processing flow is as follows: Figure 1 As shown, first clarify the structural characteristics of the combustion cylinder and determine the combustion cylinder flow area; investigate the distribution characteristics of the compressor outlet parameters, determine the combustion cylinder inlet intake form, and thus determine the corresponding combustion cylinder inlet and outlet boundary conditions; select the combustion cylinder intake mode; perform numerical simulation of the combustion cylinder under different intake conditions; obtain the combustion chamber inlet velocity parameter distribution; combine the combustion chamber inlet shape and fit the combustion chamber inlet velocity distribution function according to the combustion chamber inlet parameter distribution to preliminarily obtain the combustion chamber inlet boundary conditions; correct the combustion chamber inlet boundary conditions according to the mass flow rate to obtain the corrected combustion chamber inlet boundary conditions.

[0038] The geometric model is established as Figure 2As shown, the compressor 1 is connected to the combustion cylinder 2, and the connection section is the compressor outlet section 5. The combustion cylinder 2 is connected to the combustion chamber 3, and the combustion cylinder 2 and the combustion chamber guide sleeve 4, a component in the combustion chamber 3, form an interface combustion cylinder outlet / combustion chamber inlet section 6.

[0039] In step 1, for different combustion cylinder inlet intake forms, the corresponding combustion cylinder inlet and outlet boundary conditions are determined. The combustion cylinder inlet intake forms include uniform inlet forms and distorted inlet forms. Distorted inlet forms include radial distortion, circumferential distortion, radial-circumferential coupled distortion, and unsteady pulsation. As an example, the combustion cylinder inlet and outlet boundary conditions include inlet velocity, outlet pressure, and operating pressure. For example, radial distortion is defined by defining a parabolic curve at the inlet section: To determine, is a constant. Different constants can be selected according to the difference in the peak value of the inlet radial distortion velocity and the degree of distortion. r 1 is the radial position of the combustion cylinder inlet, V 1 is the velocity corresponding to the radial position; the circumferential distortion is defined by a parabolic curve at the inlet section: To determine, is a constant. Different constants can be selected according to the different circumferential distortion of the inlet. is the circumferential position of the combustion cylinder inlet, V 2 is the velocity corresponding to the circumferential position; the radial-circumferential coupling distortion is defined by the curve at the inlet section: To determine, 、 According to the difference of inlet radial distortion, circumferential distortion velocity peak and distortion degree, different constants can be selected. V 3 is the velocity at the corresponding position; the unsteady pulsation is defined by the curve at the inlet section: To determine, is a constant. It can be selected as a different constant according to the unsteady pulsation amplitude and the reference speed. t can be selected as a different value according to the unsteady pulsation period. V 4 The outlet gauge pressure can be set to 0, and the operating pressure is determined by the actual operating pressure of the combustion cylinder.

[0040] In step 2, the boundary conditions of the combustion cylinder inlet and outlet are input into the numerical simulation software - Fluent software for numerical simulation to obtain the corresponding combustion chamber inlet velocity distribution; Figure 3As shown in the figure, the combustion chamber inlet velocity distribution is a set of velocities distributed on an annular surface with the center of the combustion chamber outlet as the origin and the radial directions as R1 and R2, where R2 = Rmax, Rmax represents the maximum radius of the combustion chamber outlet section, R1 < R2. For example: R1 = 0.85Rmax. Affected by the combined action of the compressor outlet air flow and the combustion pressure cylinder rectification and pressure augmentation, the combustion chamber inlet velocity distribution is uneven in the circumferential and radial directions.

[0041] In step three, in combination with the combustion chamber inlet geometry (generally annular), polynomial fitting is performed on the combustion chamber inlet velocity distribution to obtain the combustion chamber inlet boundary conditions.

[0042] In the embodiment of the present invention, the description of the combustion chamber inlet velocity distribution is implemented based on a C language program. According to Figure 3 the combustion chamber inlet velocity distribution form shown in the figure, the combustion chamber is divided into multiple segments along the radial direction to form multiple segmented rings; take half of the sum of the radii of any two adjacent rings as the radius to form a middle ring circle, and unfold the multiple middle ring circles along the circumferential direction to form multiple middle ring lines, and perform polynomial fitting on the velocity distribution of each middle ring line respectively to obtain the combustion chamber inlet velocity distribution; among them, the velocity distribution of each middle ring line is obtained according to the combustion chamber inlet velocity distribution.

[0043] For example, the combustion chamber is divided into three segments along the radial direction to form three segmented rings, and the ring radii are R 11 、R 12 、R 13 , and 0.85 Rmax < R 11 < 0.9Rmax, 0.9Rmax < R 12 < 0.95Rmax, 0.95Rmax < R 13 < Rmax; select a ring line on each segmented ring to obtain the ring line velocity, obtain the velocity of the combustion chamber inlet on each ring line according to the combustion chamber inlet velocity distribution, unfold the middle ring line along the circumferential direction, and perform polynomial fitting on each middle ring line respectively to initially obtain the combustion chamber inlet velocity distribution function. In the same radial interval, the radial direction distribution of the combustion chamber outlet velocity is uniform. The polynomial form is, for example , where x is the circumferential angle, are the correction coefficients of the equation respectively.

[0044] Furthermore, a piecewise function for the fitted velocity distribution was written using a C language program, and data was transferred using the UDF (User-Defined Function) feature in Fluent software. The inlet boundary velocity distribution function described by the C language program was transferred to Fluent software using the DEFINE_PROFILE(name, t, i) macro, which modifies the inlet boundary condition. The inlet_v custom velocity inlet boundary condition was selected as the input condition for the combustion chamber inlet boundary in the numerical simulation.

[0045] In step four, the combustion chamber inlet boundary conditions are input into the numerical simulation software for calculation to obtain the combustion chamber inlet mass flow rate; the combustion chamber inlet boundary conditions are corrected according to the combustion chamber inlet mass flow rate to correct the mass flow rate deviation caused by fitting; specifically: the combustion chamber inlet mass flow rate simulation value calculated by the numerical simulation software is compared with the actual value of the combustion chamber inlet mass flow rate under real conditions. If the simulation value is higher than the actual value, the distortion curve constant term coefficient corresponding to the distorted inlet form is reduced; if the simulation value is lower than the actual value, the distortion curve constant term coefficient corresponding to the distorted inlet form is increased; the combustion chamber inlet velocity distribution corresponding to the simulation value and the actual value being equal is used as the final combustion chamber inlet boundary condition.

[0046] In the embodiment of the present invention, after the fitting function is transferred to the Fluent software, the mass flow rate of the combustion chamber inlet can be obtained by the initial calculation of the software according to the velocity distribution. The calculated mass flow rate of the combustion chamber inlet is compared with the mass flow rate of the combustion chamber inlet under the actual conditions. According to the continuity equation , where m is the mass flow rate, ρ is the fluid density, u is the fluid flow velocity, A is the flow area. According to the above equation, when the cross-sectional area and density of the fluid remain unchanged, the velocity determines the mass flow rate, and the greater the velocity, the greater the mass flow rate. Therefore, if the mass flow rate calculated in the software based on the fitting function is higher than the mass flow rate under actual conditions, the equation should be modified to reduce the constant term of the equation. Numerical size ， If the mass flow rate calculated in the software based on the fitting function is lower than the mass flow rate under actual conditions, the equation should be modified to increase the constant term of the equation. The value is adjusted until the corrected velocity distribution function is used as the combustion chamber inlet boundary condition, and the mass flow rate of the combustion chamber numerical simulation is the same as the mass flow rate under the actual conditions. Finally, the corrected combustion chamber inlet boundary condition is input into the software for calculation, and the result is as follows Figure 4 shown.

[0047] contrast Figure 5 As can be seen from the inlet velocity distribution of the combustion chamber under the uniform incoming flow conditions shown, the inlet boundary of the reburning combustion chamber proposed by the present invention can better reflect the true velocity distribution at the inlet of the reburning combustion chamber, improving the numerical simulation accuracy. The present invention can use experimental methods to verify the inlet boundary of the combustion chamber under some working conditions, and further broaden the application scope by using the verified inlet boundary condition processing method, and carry out numerical simulation research under a wider parameter range.

[0048] Another embodiment of the present invention provides a system for processing the inlet boundary conditions of a reburning combustion chamber, which system includes:

[0049] An inlet velocity distribution acquisition module, configured to: for different inlet air forms of the combustion pressure cylinder, determine the corresponding inlet and outlet boundary conditions of the combustion pressure cylinder; input the inlet and outlet boundary conditions of the combustion pressure cylinder into a numerical simulation software for numerical simulation to obtain the corresponding inlet velocity distribution of the combustion chamber; the inlet air forms of the combustion pressure cylinder include a uniform inlet form and a distorted inlet form, and the distorted inlet form includes radial distortion, circumferential distortion, radial circumferential coupling distortion, and unsteady pulsation; the inlet and outlet boundary conditions of the combustion pressure cylinder include the inlet velocity of the combustion pressure cylinder, the outlet pressure, and the operating pressure;

[0050] An inlet boundary condition acquisition module, configured to: perform polynomial fitting on the inlet velocity distribution of the combustion chamber to obtain the inlet boundary conditions of the combustion chamber;

[0051] A correction module, configured to: input the inlet boundary conditions of the combustion chamber into a numerical simulation software for calculation to obtain the inlet mass flow rate of the combustion chamber; correct the inlet boundary conditions of the combustion chamber according to the inlet mass flow rate of the combustion chamber to correct the mass flow rate deviation caused by the fitting, and use the corrected inlet velocity distribution of the combustion chamber as the final inlet boundary conditions of the combustion chamber.

[0052] In this embodiment, the inlet velocity distribution of the combustion chamber is a set of distributed velocities on an annular surface with the center of the outlet of the combustion chamber as the origin and the radial directions being R1 and R2, where R2 = Rmax, Rmax represents the maximum radius of the outlet section of the combustion pressure cylinder, and R1 < R2; the process of performing polynomial fitting on the inlet velocity distribution of the combustion chamber includes: dividing the combustion chamber into multiple segments along the radial direction to form multiple segmented rings; taking half of the sum of the radii of any two adjacent rings as the radius to form a middle ring circle, unfolding the multiple middle ring circles along the circumferential direction to form multiple middle ring lines, and performing polynomial fitting on the velocity distribution of each middle ring line respectively to obtain the inlet velocity distribution of the combustion chamber; wherein, the velocity distribution of each middle ring line is obtained according to the inlet velocity distribution of the combustion chamber.

[0053] The function of the re-ignition combustion chamber inlet boundary condition processing system described in this embodiment can be described by the aforementioned re-ignition combustion chamber inlet boundary condition processing method. Therefore, for the parts not described in detail in this embodiment, please refer to the above method embodiment and will not be repeated here.

[0054] Although the operations of the method of the present invention are described in a particular order in the drawings, this does not require or imply that the operations must be performed in this particular order, or that all illustrated operations must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0055] 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 of these aspects cannot be combined to benefit. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A method for processing boundary conditions at the inlet of a re-ignition combustion chamber, characterized in that: The following steps are involved: Step 1: Determine corresponding combustion cylinder inlet and outlet boundary conditions for different combustion cylinder inlet intake forms; the combustion cylinder inlet intake forms include uniform inlet forms and distorted inlet forms, wherein the distorted inlet forms include radial distortion, circumferential distortion, radial-circumferential coupled distortion, and unsteady pulsation; the combustion cylinder inlet and outlet boundary conditions include the combustion cylinder inlet velocity, outlet pressure, and operating pressure; specifically, the following steps are performed: Radial distortion is achieved by defining a parabolic curve at the inlet section: V1 = a1r1 2 +b1r1+c1, where a1, b1, c1 are constants, r1 is the radial position of the combustion cylinder inlet, and V1 is the speed at the corresponding radial position; Circumferential distortion is defined by a parabolic curve at the inlet section: V2 = a2θ1 2 +b2θ1+c2, where a2, b2, c2 are constants, θ1 is the circumferential position of the combustion cylinder inlet, and V2 is the speed at the corresponding circumferential position; The radial-circumferential coupling distortion is defined by the curve at the inlet section: V3 = (a1r1 2 +b1r1+c1)·(a2θ1 2 +b2θ1+c2), where a1, b1, c1, a2, b2, c2 are different constants, and V3 is the velocity at the corresponding position; Unsteady pulsation is determined by defining a curve at the inlet section: V4 = a4 sin t + b4, where a4 and b4 are constants, t is selected according to the unsteady pulsation period, and V4 is the inlet velocity; Step 2: Input the boundary conditions of the combustion chamber inlet and outlet into the numerical simulation software for numerical simulation to obtain the corresponding combustion chamber inlet velocity distribution; the combustion chamber inlet velocity distribution is a set of distributed velocities on the annular surface with the center of the combustion chamber outlet as the origin and radial directions R1 and R2, where R2 = Rmax, Rmax represents the maximum radius of the combustion chamber outlet section, and R1 <R2; Step 3: Perform polynomial fitting on the combustion chamber inlet velocity distribution to obtain the combustion chamber inlet boundary conditions.

2. A method for processing boundary conditions at the inlet of a re-ignition combustion chamber according to claim 1, characterized in that: The method further includes the step of inputting the combustion chamber inlet boundary conditions into a numerical simulation software for calculation to obtain the combustion chamber inlet mass flow rate; The combustion chamber inlet boundary condition is corrected according to the combustion chamber inlet mass flow rate to correct the mass flow rate deviation caused by fitting, and the corrected combustion chamber inlet velocity distribution is used as the final combustion chamber inlet boundary condition.

3. A method for processing boundary conditions at the inlet of a re-ignition combustion chamber according to claim 1 or 2, characterized in that: The specific process of step three includes: dividing the combustion chamber into multiple sections along the radial direction to form multiple segmented circular rings; taking half of the sum of the radii of any two adjacent circular rings as the radius to form a middle ring circle, and expanding the multiple middle ring circles along the circumferential direction to form multiple middle ring lines, and performing polynomial fitting on the velocity distribution of each middle ring line to obtain the velocity distribution at the combustion chamber inlet; wherein, the velocity distribution of each middle ring line is obtained based on the velocity distribution at the combustion chamber inlet.

4. A method for processing boundary conditions at the inlet of a re-ignition combustion chamber according to claim 2, characterized in that: The process of correcting the combustion chamber inlet boundary condition according to the combustion chamber inlet mass flow in step four includes: comparing the combustion chamber inlet mass flow simulation value calculated by numerical simulation software with the actual value of the combustion chamber inlet mass flow under real conditions; if the simulation value is higher than the actual value, reducing the distortion curve constant term coefficient corresponding to the distorted inlet form; if the simulation value is lower than the actual value, increasing the distortion curve constant term coefficient corresponding to the distorted inlet form; and taking the combustion chamber inlet velocity distribution corresponding to when the simulation value and the actual value are equal as the final combustion chamber inlet boundary condition.

5. A system for processing boundary conditions at the inlet of a re-ignition combustion chamber, characterized in that: include: The inlet velocity distribution acquisition module is configured to: determine the corresponding combustion cylinder inlet and outlet boundary conditions for different combustion cylinder inlet intake forms; input the combustion cylinder inlet and outlet boundary conditions into the numerical simulation software for numerical simulation to obtain the corresponding combustion chamber inlet velocity distribution; the combustion cylinder inlet intake forms include uniform inlet forms and distorted inlet forms, and the distorted inlet forms include radial distortion, circumferential distortion, radial-circumferential coupling distortion and unsteady pulsation; the combustion cylinder inlet and outlet boundary conditions include the combustion cylinder inlet velocity, outlet pressure and operating pressure; specifically, the radial distortion is obtained by defining a parabolic curve at the inlet section: V1 = a1r1 2 +b1r1+c1, where a1, b1, c1 are constants, r1 is the radial position of the combustion cylinder inlet, and V1 is the speed at the corresponding radial position; the circumferential distortion is determined by defining a parabolic curve at the inlet section: V2=a2θ1 2 +b2θ1+c2, where a2, b2, c2 are constants, θ1 is the circumferential position of the combustion cylinder inlet, and V2 is the speed at the corresponding circumferential position; the radial circumferential coupling distortion is determined by defining the curve at the inlet section: V3=(a1r1 2 +b1r1+c1)·(a2θ1 2 +b2θ1+c2), where a1, b1, c1, a2, b2, c2 are different constants, and V3 is the velocity at the corresponding position; the unsteady pulsation is determined by defining a curve at the inlet section: V4=a4·sin t+b4, where a4 and b4 are constants, t is selected according to the unsteady pulsation period, and V4 is the inlet velocity; the combustion chamber inlet velocity distribution is a set of distributed velocities on a circular surface with the center of the combustion chamber outlet as the origin and radial directions R1 and R2, where R2=Rmax, Rmax represents the maximum radius of the combustion cylinder outlet section, and R1 <R2; The inlet boundary condition acquisition module is configured to perform polynomial fitting on the combustion chamber inlet velocity distribution to obtain the combustion chamber inlet boundary condition.

6. A re-ignition combustion chamber inlet boundary condition processing system according to claim 5, characterized in that: The system further includes a correction module configured to: input the combustion chamber inlet boundary conditions into a numerical simulation software for calculation to obtain the combustion chamber inlet mass flow rate; The combustion chamber inlet boundary condition is corrected according to the combustion chamber inlet mass flow rate to correct the mass flow rate deviation caused by fitting, and the corrected combustion chamber inlet velocity distribution is used as the final combustion chamber inlet boundary condition.

7. A re-ignition combustion chamber inlet boundary condition processing system according to claim 5 or 6, characterized in that: The process of performing polynomial fitting on the combustion chamber inlet velocity distribution in the inlet boundary condition acquisition module includes: dividing the combustion chamber into multiple segments along the radial direction to form multiple segmented circular rings; taking half of the sum of the radii of any two adjacent circular rings as the radius to form a middle ring circle, and expanding the multiple middle ring circles along the circumferential direction to form multiple middle ring lines, and performing polynomial fitting on the velocity distribution of each middle ring line to obtain the combustion chamber inlet velocity distribution; wherein the velocity distribution of each middle ring line is obtained based on the combustion chamber inlet velocity distribution.

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