Quasi-3D design method for centrifugal compressor impeller based on inverse design algorithm

Abstract

The present application discloses a quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm, wherein the method includes making a preliminary guess of an unknown flow channel wall surface through a ball-and-spine algorithm; generating a computational grid; performing a quasi-3D analysis of the impeller meridian plane by specifying input parameters to obtain an inner target decompression distribution; calculating the difference between the current inner decompression distribution and the target inner decompression distribution; determining whether the current inner decompression distribution is close to the target inner decompression distribution, if so, stopping the deformation of the flow channel wall surface and obtaining the target shape; if not, calculating the displacement of the flow channel wall surface and updating the geometric shape of the flow channel wall surface, and returning to computational grid generation. The present application is beneficial in that it provides a quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm, which improves the impeller performance by improving the meridian plane through inverse design of the flow channel decompression distribution.

Description

Technical Field

[0001] The present application relates to the field of impeller design, and in particular to a quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm. Background Art

[0002] With the rapid development of industries such as chemical, aerospace, navigation, and military, the demand for centrifugal compressors has gradually increased. As a result, the requirements for centrifugal compressor flow, pressure, efficiency, and R&D costs have become increasingly higher.

[0003] Centrifugal compressors are widely used in various process flows to transport air, various process gases, or mixed gases and increase their pressure. In centrifugal compressors, the centrifugal force exerted by the high-speed rotating impeller and the diffusion of the gas in the diffuser channel increase the gas pressure. In the early days, these compressors were only suitable for low- and medium-pressure, high-flow applications. With the development of the chemical industry and the establishment of large-scale chemical plants and refineries, centrifugal compressors have become crucial machines for compressing and transporting various gases in chemical production, occupying an extremely important position. Improving the overall performance of centrifugal compressors is crucial for energy conservation, emission reduction, and improving economic efficiency. Summary of the Invention

[0004] The content of this application is used to briefly introduce concepts that will be described in detail in the detailed description section below. The content of this application is not intended to identify key features or essential features of the technical solution for which protection is sought, nor is it intended to limit the scope of the technical solution for which protection is sought.

[0005] Some embodiments of the present application propose a quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm to solve the technical problems mentioned in the above background technology section. The method includes: making a preliminary guess on the unknown flow channel wall through the ball-and-thorn algorithm; generating a computational grid; performing a quasi-three-dimensional analysis on the impeller meridian plane with specified input parameters to obtain an inner target decompression distribution; calculating the difference between the current inner decompression distribution and the target inner decompression distribution; judging whether the current inner decompression distribution is close to the target inner decompression distribution, if so, stopping the deformation of the flow channel wall and obtaining the target shape; if not, calculating the displacement of the flow channel wall and updating the geometric shape of the flow channel wall, and returning to computational grid generation.

[0006] Furthermore, the spherical-spine algorithm is used to make a preliminary guess about the unknown channel wall, including: defining the channel wall as a two-dimensional flexible channel composed of a set of virtual spheres that move freely in a specified direction, applying a target pressure reduction distribution on the outside of each channel wall, and the channel wall will deform to meet the target pressure reduction distribution on the inside; assuming that the mass is uniformly distributed along the wall, the kinematic relationship of the channel wall is as follows:

[0007]

[0008]

[0009] In the above formula, F s represents the force on the virtual ball on the spine, ΔP represents the difference between the target decompression distribution and the current decompression distribution, A represents the local force area of ​​the flow channel wall, θ represents the angle between the force direction of the virtual ball and the spine, and a s represents the acceleration, and Δy represents the displacement required to achieve the target decompression distribution on the inside;

[0010] Based on the surface density of the flow channel wall, equation (1-2) is converted to the following formula:

[0011]

[0012] In the above formula, ρ represents the surface density of the channel wall;

[0013] The new position of each virtual ball is obtained by the following formula:

[0014]

[0015]

[0016] In the above formula, x i represents the displacement in the x direction, y i represents the displacement in the y direction, ΔP i represents the difference between the target decompression profile and the current decompression profile, θ i It represents the angle between the force direction of the virtual ball and the spine.

[0017] Furthermore, the input parameters include one or more of mass flow rate, rotation speed, number of blades, specific heat ratio, gas constant, inlet angle, total inlet temperature and total inlet density.

[0018] Furthermore, the input parameters also include one or more of a hub-to-shroud profile, an average blade shape, and a normal thickness distribution of the blade.

[0019] Furthermore, in calculating the displacement of the flow channel wall, the difference between the current inside pressure and the target inside pressure is applied to each virtual ball on the wall. The displacement of each virtual ball along its spine is given by the following formula:

[0020]

[0021] In the above formula, Δs i represents the displacement of the channel wall; ρ represents the surface density of the channel wall; P r-target(i) represents the target decompression distribution; P r (i) represents the current decompression; θ i It represents the angle between the force direction of the virtual ball and the spine;

[0022] In inviscid flow, the stagnation pressure and relative stagnation pressure of the stationary flow channel and the rotating flow channel are constant, respectively. Then:

[0023]

[0024]

[0025] Decompression is defined as follows:

[0026]

[0027] The relative stagnation pressure is rewritten as:

[0028]

[0029] In the above formula, P0 represents the stagnation pressure, P represents the static pressure, and P 0r represents relative stagnation pressure, Pr represents reduced pressure, ρ represents wall surface density, W represents relative velocity, ω represents angular velocity, V represents fluid velocity, and R represents impeller radius.

[0030] Furthermore, the decompression at the flow channel inlet is used as the inlet boundary condition for the quasi-3D analysis, and the first virtual sphere on the flow channel wall is kept fixed.

[0031] Furthermore, the quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm further includes:

[0032] Three-dimensional numerical simulations are used to validate the quasi-three-dimensional analysis.

[0033] Furthermore, the use of three-dimensional numerical simulation to verify the quasi-three-dimensional analysis includes: comparing the wheel hub decompression distribution obtained by the quasi-three-dimensional analysis with the results of the three-dimensional numerical simulation; comparing the decompression distribution on the shroud calculated by the quasi-three-dimensional, three-dimensional numerical simulation and experimental measurement results; and comparing the quasi-three-dimensional analysis and three-dimensional analysis results of the decompression on the wheel hub and the shroud.

[0034] The beneficial effect of the present application is that it provides a quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm, which improves the meridian plane by performing inverse design through flow channel decompression distribution to improve impeller performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings constituting a part of this application are used to provide a further understanding of this application and make other features, purposes and advantages of this application more apparent. The drawings and descriptions of the exemplary embodiments of this application are used to explain this application and do not constitute an improper limitation on this application.

[0036] In addition, throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and that the elements and components are not necessarily drawn to scale.

[0037] In the attached figure:

[0038] Figure 1 1 is a schematic diagram of the main steps of a quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm according to an embodiment of the present application;

[0039] Figure 2 1 is a schematic diagram of flow channel wall deformation based on a ball-and-thorn algorithm in a quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm according to an embodiment of the present application;

[0040] Figure 3 This is a schematic diagram of the decompression distribution and flow channel shape of the first design in the quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm according to an embodiment of the present application;

[0041] Figure 4 1 is a schematic diagram of the decompression distribution and flow channel shape of the second design in the quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm according to an embodiment of the present application;

[0042] Figure 5 1 is a schematic diagram of the decompression distribution and flow channel shape of the third design in the quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm according to an embodiment of the present application;

[0043] Figure 6 1 is a schematic diagram of the decompression distribution and flow channel shape of the fourth design in the quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm according to an embodiment of the present application;

[0044] Figure 7 This is a schematic diagram of the efficiency of the fourth design in the quasi-three-dimensional design method for a centrifugal compressor impeller based on an inverse design algorithm according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for illustrative purposes only and are not intended to limit the scope of protection of the present disclosure.

[0046] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0047] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0048] It should be noted that the modifications of "one" and "multiple" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, they should be understood as "one or more".

[0049] The names of the messages or information exchanged between multiple devices in the embodiments of the present disclosure are only used for illustrative purposes and are not used to limit the scope of these messages or information.

[0050] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0051] To facilitate understanding of the technical solution of this application, some of the terms and concepts used in this application are explained below:

[0052] Target pressure reduction: The pressure drop you want to achieve.

[0053] Current Decompression: The pressure drop at the current state.

[0054] Ball-and-spine algorithm: This algorithm is used for the inverse design of centrifugal impellers. In this algorithm, the unknown channel wall is composed of a set of virtual spheres, called spines, that are free to move along specified directions. The difference between the target pressure distribution and the current pressure distribution at each modification step acts as a force that causes the wall to deform. Once the target shape is reached, the difference between the target and current pressure distributions disappears, and the wall deformation automatically ceases. The ball-and-spine algorithm transforms the inverse design problem into a physics-based analysis of fluid-structure interaction, resulting in a fast-converging method.

[0055] Mesh generation: In computational fluid dynamics, a collection of discrete points distributed in the flow field according to a certain pattern is called a mesh, and the process of generating these nodes is called mesh generation.

[0056] Quasi-3D Analysis: To determine the average blade shape of a radial impeller, the initial model and various parameters are input into the solver. Once the solution converges, the reduced pressure distribution on the hub and shroud surfaces, the static pressure distribution on the radial plane, the reduced pressure distribution on the meridian plane, and the relative velocity distribution on the meridian plane are obtained.

[0057] Mass flow rate: The mass of fluid passing through the effective cross-section of a closed pipe or open slot per unit time.

[0058] Diffuser: Used to reduce fluid velocity and increase fluid static pressure.

[0059] like Figure 1 As shown, the quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm of the present application mainly includes the following steps:

[0060] S1: Make a preliminary guess about the unknown flow channel wall using the ball-and-thorn algorithm.

[0061] S2: Computational grid generation.

[0062] S3: Specify input parameters to perform a quasi-3D analysis on the impeller meridian plane to obtain the target pressure reduction distribution on the inner side.

[0063] S4: Calculating a difference between the current inner decompression profile and the target inner decompression profile.

[0064] S5: Determine whether the current inner pressure reduction distribution is close to the target inner pressure reduction distribution. If so, the deformation of the flow channel wall stops and the target shape is obtained; if not, calculate the displacement of the flow channel wall and update the geometric shape of the flow channel wall, and return to the computational mesh generation.

[0065] S6: Validate the quasi-3D analysis using 3D numerical simulations.

[0066] As a specific solution, step S1 specifically includes the following steps:

[0067] S11: Define a two-dimensional variable flow channel (also called a "flexible flow channel") formed by a set of virtual spheres that move freely in a specified direction. Apply a target pressure reduction distribution on the outside of each flow channel wall, and the flow channel wall will deform to achieve the target pressure reduction distribution on the inside. Assuming that the mass is uniformly distributed along the wall, the kinematic relationship of the flow channel wall is as follows:

[0068]

[0069]

[0070] In the above formula, F s represents the force on the virtual ball on the spine, ΔP represents the difference between the target decompression distribution and the current decompression distribution, A represents the local force area of ​​the flow channel wall, θ represents the angle between the force direction of the virtual ball and the spine, and a s represents the acceleration, and Δy represents the displacement required to achieve the target decompression distribution on the inside;

[0071] Fluid passing through the variable flow channel causes a pressure reduction profile to be applied to the inner side of the channel walls. If a target pressure reduction profile is applied to the outer side of each channel wall, the flexible wall deforms to achieve a shape that satisfies the inner target pressure reduction profile. This inner target pressure reduction profile is derived from a quasi-3D analysis of the impeller meridian plane. The force generated by the difference between the target inner pressure reduction profile and the current inner pressure reduction profile at each point on the wall is applied to each virtual sphere, forcing it to move. When the target shape is achieved, the pressure difference theoretically disappears.

[0072] Considering that the virtual balls move along the direction of the applied force, adjacent virtual balls may collide or move with each other, which may interfere with the flow channel wall modification procedure. To avoid this problem, Figure 2 As shown, the concept of spines is added to enable the virtual ball to move freely in the specified direction.

[0073] S12: Based on the surface density of the flow channel wall, the following formula is obtained by converting formula (1-2):

[0074]

[0075] In the above formula, ρ represents the surface density of the channel wall; Δt is the interval between ball movements during each shape modification step. The parameter Δt² / ρ adjusts the convergence speed of the ball-and-spine algorithm. Lower values ​​of Δt² / ρ result in slower convergence. In fact, if Δt² / ρ is too high, the design algorithm will diverge.

[0076] S13: The new position of each virtual ball is obtained by the following formula:

[0077]

[0078]

[0079] In the above formula, x i represents the displacement in the x direction, y i represents the displacement in the y direction, ΔP i represents the difference between the target decompression profile and the current decompression profile, θ i It represents the angle between the force direction of the virtual ball and the spine.

[0080] In the meridional plane of a centrifugal compressor, the outlet radius is fixed, not the horizontal length.

[0081] As a specific solution, in step S3, the input parameters include mass flow rate, rotation speed, number of blades, specific heat ratio, gas constant, inlet angle, inlet total temperature, inlet total density, hub-to-shroud profile, average blade shape, normal thickness distribution of blades, etc. The mass flow rate, rotation speed, inlet total temperature, and inlet total density are obtained by experimental measurement of the design point defined at the compressor inlet.

[0082] Specifically, in step S4, the calculated pressure surface is typically obtained from a partially converged numerical solution of the flow equations. During the iterative design process, as the current pressure reduction profile approaches the target pressure reduction profile, the forces exerted on the flexible wall gradually disappear. Subsequent solutions to the flexible wall equations do not result in changes in the pipe surface coordinates.

[0083] The pressure reduction perceived from a rotating channel wall is similar to the static pressure perceived from a stationary channel wall. Therefore, the growth of boundary layer thickness along a rotating channel wall depends on the reduced pressure gradient. As a specific scheme, in calculating the displacement of the channel wall, the difference between the current inside pressure and the target inside pressure is applied to each virtual ball on the wall. The displacement of each virtual ball along its spine is given by the following formula:

[0084]

[0085] In the above formula, Δs i represents the displacement of the channel wall; ρ represents the surface density of the channel wall; P r-target (i) represents the target decompression distribution; P r (i) represents the current decompression; θ i It represents the angle between the force direction of the virtual ball and the spine;

[0086] In inviscid flow, the stagnation pressure and relative stagnation pressure of the stationary flow channel and the rotating flow channel are constant, respectively. Then:

[0087]

[0088]

[0089] Decompression is defined as follows:

[0090]

[0091] The relative stagnation pressure is rewritten as:

[0092]

[0093] In the above formula, P0 represents the stagnation pressure, P represents the static pressure, and P0r represents relative stagnation pressure, Pr represents reduced pressure, ρ represents wall surface density, W: represents relative velocity, ω represents angular velocity, V represents fluid velocity, and R represents impeller radius.

[0094] The stagnation pressure P0, static pressure P and velocity V are respectively replaced by the relative stagnation pressure P 0r , pressure reduction Pr and relative velocity W. The pressure felt from the rotating flow channel wall is just like the static pressure felt from the stationary duct wall.

[0095] Since the starting point of each wall should be fixed during the design process, the inlet decompression is used as the inlet boundary condition of the quasi-3D analysis code, and the first virtual sphere on the wall is kept fixed.

[0096] As a specific solution, three-dimensional numerical simulation is used to verify the quasi-three-dimensional analysis, including:

[0097] 1) Compare the wheel hub decompression distribution obtained from quasi-3D analysis with the results of 3D numerical simulation;

[0098] 2) Compare the decompression distribution on the shield calculated by quasi-3D and 3D numerical simulations and experimental measurements;

[0099] 3) Compare the results of the quasi-3D analysis and the 3D analysis of the decompression on the hub and shroud.

[0100] After verifying the quasi-3D analysis results, the ball-and-thorn algorithm was incorporated into the quasi-3D code, and the hub and shroud profiles of the impeller were obtained by modifying the decompression distribution along the hub and shroud.

[0101] like Figure 3 In the design shown (hereinafter referred to as Design A), the corresponding shapes of the hub and shroud surfaces are obtained after modifying the current pressure reduction distribution. In Design A, the additional adverse pressure gradient along the shroud surface is eliminated, but the inlet and outlet pressures are not changed, that is, the area ratio is kept fixed, and it attempts to make it smooth. In addition, as Figure 3 As shown, the axial length of the improved impeller is reduced by 5%.

[0102] like Figure 4 In the design shown (hereafter referred to as Design B), the outlet pressure is slightly increased, resulting in an increase in the area ratio. In addition, the adverse pressure gradient along the shroud surface is lower than that of Design A, which will reduce the degree of boundary layer thickening on the shroud surface. The deflection angle from the inlet to the outlet depends on the pressure reduction distribution along the hub surface and the surrounding area of ​​the shroud surface. Figure 4 As shown, the corrected pressure in the surrounding area increases compared to the original situation.

[0103] like Figure 5The design shown (hereafter referred to as Design C) attempts to achieve a minimum adverse pressure gradient on the shroud surface, maintaining constant inlet and outlet pressures, as well as pressures in the areas surrounding the hub and shroud surfaces, and thus the degree of deflection. In this case, the axial length of the modified impeller is reduced by 10%. The modifications in Design C reduce boundary layer losses, the effective blade area (radial planar area), and the average pressure level on the blade. This results in the blade performing work on the fluid with a smaller pressure and area of ​​influence. Consequently, the pressure ratio of the impeller in Design C is expected to be lower.

[0104] In Designs A, B, and C, modifications to the impeller hub and shroud surfaces resulted in a change in the impeller's axial length. Separation along the shroud surface is easier than separation along the hub. Therefore, to improve the geometry in the meridian plane without changing the axial length, the hub geometry was kept fixed and only the shroud geometry was modified. Consequently, the automatically obtained pressure reduction distribution along the hub surface became uncontrolled.

[0105] To specify a target pressure reduction distribution along the shroud surface, two points should be considered:

[0106] a: The pressure applied to the fluid in the rotating domain is a reduced pressure. When the fluid flows out of the impeller rotating domain, the pressure applied to the fluid changes from reduced pressure to static pressure, that is, the fluid faces 1 / 2ρr 2 ω 2 The pressure mutation causes the tail flow at the impeller outlet to be enhanced. In order to overcome this pressure mutation, the fluid must be accelerated before it leaves the impeller. The slope of the decompression distribution on the hub surface is negative, and the fluid is accelerated before leaving the impeller. This is mainly related to the shroud surface where the decompression is increased. The advantage of the decompression distribution along the shroud surface is that the decompression slope at the impeller outlet is negative, and the fluid is accelerated before flowing out of the impeller. Figure 6 In the design shown (hereafter referred to as Design D), the pressure drop along the shroud curve increases and then decreases suddenly.

[0107] b: In the most efficient diffuser, the flow path experiences high-pressure loading in the first section and then flattens out at its end, as shown by the target reduced-pressure profile for Design D.

[0108] The three-dimensional numerical simulation of Design D shows that the efficiency of this design is 0.6% higher than that of the original design. The increase in efficiency relative to the normalized rotational speed is shown in Figure 7 In the 3D numerical simulation, the mesh generation of the modified impeller is no different from that of the current impeller.

[0109] This paper uses a ball-and-spine algorithm design program combined with a quasi-3D analysis code to design the hub and shroud surface profiles of a centrifugal compressor impeller. To ensure convergence of the ball-and-spine algorithm within the rotational region, the difference between the target and current pressure reduction profiles is applied at each shape modification step. The target pressure reduction profile on the shroud surface exhibits high loads in the first section of the flow path, moderates in the middle, and terminates with negative values ​​in the final section. The design program converges to the shroud surface profile, resulting in a 0.6% improvement in compressor efficiency.

[0110] The quasi-three-dimensional design method for centrifugal compressor impellers based on the inverse design algorithm of the present application can be applied to the impeller design of centrifugal compressors, centrifugal fans, centrifugal pumps, etc.

[0111] The above description is only an illustration of some preferred embodiments of the present disclosure and the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure.

Claims

1. A quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm, characterized by: include: Make a preliminary guess about the unknown channel wall using the ball-and-thorn algorithm; Computational grid generation; Specify input parameters to perform quasi-3D analysis on the impeller meridian plane to obtain the target pressure reduction distribution inside. Calculating the difference between the current medial decompression profile and the target medial decompression profile; Determine whether the current inner pressure reduction distribution is close to the target inner pressure reduction distribution. If so, stop the deformation of the channel wall and obtain the target shape. If not, calculate the displacement of the channel wall and update the geometric shape of the channel wall, and return to the computational mesh generation. The ball-and-spine algorithm is used to make a preliminary guess about the unknown flow channel wall, including: The flow channel wall is defined as a two-dimensional flexible flow channel consisting of a set of virtual spheres that move freely in a specified direction. When a target pressure reduction distribution is applied to the outside of each flow channel wall, the flow channel wall will deform to meet the target pressure reduction distribution on the inside. Assuming that the mass is uniformly distributed along the wall, the kinematic relationship of the flow channel wall is as follows: （1-1） （1-2） In the above formula, F s represents the force on the virtual ball on the spine, ΔP represents the difference between the target decompression distribution and the current decompression distribution, A represents the local force area of ​​the flow channel wall, θ represents the angle between the force direction of the virtual ball and the spine, and a s represents the acceleration, and Δy represents the displacement required to achieve the target decompression distribution on the inside; Based on the surface density of the flow channel wall, the following formula is obtained by converting formula (1-2): （1-3） In the above formula, ρ represents the surface density of the channel wall; The new position of each virtual ball is obtained by the following formula: （1-4） （1-5） In the above formula, x i represents the displacement in the x direction, y i represents the displacement in the y direction, ΔP i represents the difference between the target decompression profile and the current decompression profile, θ i It represents the angle between the force direction of the virtual ball and the spine.

2. The quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm according to claim 1, characterized in that: The input parameters include one or more of mass flow rate, rotation speed, number of blades, specific heat ratio, gas constant, inlet angle, inlet total temperature and inlet total density.

3. The quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm according to claim 2, characterized in that: The input parameters also include one or more of a hub-to-shroud profile, an average blade shape, and a normal thickness distribution of the blades.

4. The quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm according to claim 1, characterized in that: In calculating the displacement of the flow channel wall, the difference between the current inside pressure and the target inside pressure is applied to each virtual ball on the wall. The displacement of each virtual ball along its spine is given by the following formula: （2-1） In the above formula, Δs i represents the displacement of the channel wall; ρ represents the surface density of the channel wall; P r-target (i) represents the target decompression; P r (i) indicates the current decompression; θ i It represents the angle between the force direction of the virtual ball and the spine; In inviscid flow, the stagnation pressure and relative stagnation pressure of the stationary flow channel and the rotating flow channel are constant, respectively. Then: （2-2） （2-3） Decompression is defined as follows: （2-4） The relative stagnation pressure is rewritten as: （2-5） In the above formula, P0 represents the stagnation pressure, P represents the static pressure, and P 0r represents relative stagnation pressure, Pr represents reduced pressure, ρ represents wall surface density, W represents relative velocity, ω represents angular velocity, V represents fluid velocity, and R represents impeller radius.

5. The quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm according to claim 4, characterized in that: The decompression at the flow channel inlet is used as the inlet boundary condition for the quasi-3D analysis, and the first virtual sphere on the flow channel wall is kept fixed.

6. The quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm according to claim 1, characterized in that: The quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm further includes: Three-dimensional numerical simulations are used to validate the quasi-three-dimensional analysis.

7. The quasi-3D design method for a centrifugal compressor impeller based on an inverse design algorithm according to claim 6, characterized in that: The use of three-dimensional numerical simulation to verify the quasi-three-dimensional analysis includes: The wheel hub decompression distribution obtained from quasi-3D analysis is compared with the results of 3D numerical simulation; The decompression distribution on the shroud calculated by quasi-3D and 3D numerical simulations and experimental measurements are compared; The results of a quasi-3D analysis and a 3D analysis of the pressure reduction on the hub and shroud are compared.

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