A method for collaborative design of an orthogonal blade and a streamline end wall of a high-pressure-ratio centrifugal compressor
By combining orthogonal blades with streamlined endwalls, the problem of sharp angle effect and corner separation caused by the monotonous endwall shape in high-pressure centrifugal compressors is solved, resulting in reduced total pressure loss and improved overall stage efficiency, a wider stable operating range, and ensured intake quality for downstream impellers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN ENG UNIV
- Filing Date
- 2026-04-01
- Publication Date
- 2026-06-26
Smart Images
Figure CN122286992A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of turbomachinery aerodynamic design technology, and more specifically to a method for the collaborative design of orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor. Background Technology
[0002] In the field of modern energy conversion and propulsion, centrifugal compressors are developing towards higher pressure ratios and higher efficiency. When the total pressure ratio at the design point of a two-stage centrifugal compressor reaches 18 or even higher, the internal flow environment of the reflux unit, as a key component connecting the diffuser outlet and the inlet of the next stage impeller, is extremely harsh.
[0003] Traditional return flow design often uses ruled blades and simple arc-shaped meridional channels. Although this design is convenient for side milling, it has significant aerodynamic defects: (1) Acute Angle Effect: The leading edge of the blade and the endwall usually intersect at an acute angle, forming a contracting wedge-shaped space. This leads to the intensification of horseshoe vortices and the generation of a "funnel effect", which collects the transverse flow of the endwall and the radial flow of the blade, inducing severe three-dimensional separation and blockage in the corner region. (2) Insufficient diffusion control: Simple linear or arc-shaped endwalls cannot finely control the development of the boundary layer under high adverse pressure gradients, which can easily lead to rapid thickening or even separation of the boundary layer.
[0004] Existing one-dimensional calculations or simple three-dimensional designs can no longer meet the needs of high-performance compression systems. There is an urgent need for a collaborative design method that can suppress corner separation and finely control channel diffusion from a geometric perspective.
[0005] Therefore, proposing a collaborative design method for orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor to address the difficulties in the existing technology is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0006] In view of this, the present invention provides a method for the coordinated design of orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor, which solves the problems of severe corner separation and poor interstage matching caused by acute angle effect and monotonous endwall shape in the prior art.
[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for the coordinated design of orthogonal blades and streamlined endwalls in a high-pressure ratio centrifugal compressor includes the following steps: S1. Based on the overall design requirements of the compressor, determine the aerodynamic parameter boundary conditions and geometric constraints of the reflux inlet and outlet; S2. Establish a parameterized model of the blade, apply geometric orthogonal constraints at the intersection of the blade leading edge and the hub and cover, and generate a meridional aerodynamic orthogonal blades. S3. Establish a parameterized model of the end wall, use high-order curves to define the meridional profile of the hub and wheel cover, and introduce nonlinear control points to adjust the cross-sectional area distribution of the flow channel. S4. Construct a collaborative optimization platform and define the objective function; S5. Combining three-dimensional numerical calculation and optimization algorithms, the orthogonal parameters and endwall shape parameters of the blade are iteratively optimized until the objective function converges, and the optimal design scheme is obtained.
[0008] Optionally, the process of generating meridional aeroorthogonal blades in S2 includes: Abandoning ruled surface modeling, three-dimensional twisted surface modeling technology is adopted; The orthogonal constraint condition is set as follows: at the intersection of the leading edge and the endwall of the blade, the tangent vector of the leading edge of the blade is... Tangent vector to the end wall meridian The dot product is zero, that is... ; Orthogonal design eliminates the acute-angled wedge-shaped region formed by the blade stacking line and the endwall, suppressing the migration of the horseshoe vortex pressure surface branch to the suction surface.
[0009] Optionally, the process of establishing the end-wall parameterized model in S4 includes: The end-wall meridian is defined using Bézier curves or B-spline techniques; By adjusting the radial coordinates of the control points and axial coordinates A localized constriction channel is constructed in the region near the leading edge of the blade to accelerate the fluid first, suppress flow separation, and then allow for controlled diffusion. By adjusting the local curvature of the endwall, a pressure gradient opposite to the direction of the secondary flow driving force is constructed, thus hindering the migration of the transverse secondary flow.
[0010] Optionally, the mechanism of localized contraction channels is as follows: according to the continuity equation, the mainstream is accelerated, the boundary layer shape factor H is reduced, the boundary layer is re-laminated or thinned, and the ability to resist subsequent adverse pressure gradients is enhanced, followed by controlled diffusion.
[0011] Optionally, the process of establishing the endwall parameterization model in S4 also includes: constructing a pressure gradient in the direction perpendicular to the streamlines and opposite to the direction of the secondary flow driving force by adjusting the local concavity and convexity curvature of the endwall. To hinder the migration of lateral secondary flows.
[0012] Optionally, in S4, the process of constructing a collaborative optimization platform based on computational fluid dynamics and global optimization algorithms, and setting the objective function, includes: The set multi-objective functions include maximizing the stage multivariable efficiency, maximizing the surge margin, minimizing the total pressure loss coefficient, and constraining the residual swirl at the outlet of the return flow device, requiring the outlet airflow angle to be close to the axial direction in order to eliminate the intake distortion of the downstream impeller.
[0013] Optionally, the optimization algorithm in S5 can be either a gradient-based adjoint method or a surrogate model-based global optimization algorithm. The global optimization algorithm based on the surrogate model includes: selecting sample points in the design space using Latin hypercube sampling, constructing the response surface using the Kriging model or artificial neural network, and searching for the Pareto optimal solution using a multi-objective genetic algorithm.
[0014] Optionally, the objective function in S5 also includes constraints on the residual swirl at the outlet of the return flower, requiring the outlet airflow angle to be close to the axial direction in order to eliminate intake distortion to the downstream impeller.
[0015] As can be seen from the above technical solution, compared with the prior art, the present invention provides a method for the coordinated design of orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor, which has the following beneficial effects: (1) This invention utilizes orthogonal design to eliminate the "funnel effect" in the acute angle region from the source. Combined with the obstruction effect of the endwall shape on the secondary flow, it significantly suppresses flow separation in the corner region, and the total pressure loss can be reduced by 5%-10%. The nonlinear endwall improves the boundary layer state, and the orthogonal blades broaden the adaptability to different angles of attack, thereby improving the overall stage efficiency by 0.7%-1.5% and significantly widening the stable operating range. By optimizing the outlet swirl and distortion, it provides uniform air intake conditions for the downstream high-pressure stage impeller, avoiding premature stall of the downstream impeller. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0017] Figure 1 The present invention provides a flowchart of a method for the collaborative design of orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor. Detailed Implementation
[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] See Figure 1 As shown, this invention discloses a method for the coordinated design of orthogonal blades and streamlined endwalls in a high-pressure ratio centrifugal compressor, comprising the following steps: S1. Based on the overall design requirements of the compressor, determine the aerodynamic parameter boundary conditions and geometric constraints of the reflux inlet and outlet; S2. Establish a parameterized model of the blade, apply geometric orthogonal constraints at the intersection of the blade leading edge and the hub and cover, and generate a meridional aerodynamic orthogonal blades. S3. Establish a parameterized model of the end wall, use high-order curves to define the meridional profile of the hub and wheel cover, and introduce nonlinear control points to adjust the cross-sectional area distribution of the flow channel. S4. Construct a collaborative optimization platform and define the objective function; S5. Combining three-dimensional numerical calculation and optimization algorithms, the orthogonal parameters and endwall shape parameters of the blade are iteratively optimized until the objective function converges, and the optimal design scheme is obtained.
[0020] Furthermore, the process of generating meridional aerodynamic orthogonal blades in S2 includes: Abandoning ruled surface modeling, three-dimensional twisted surface modeling technology is adopted; The orthogonal constraint condition is set as follows: at the intersection of the leading edge and the endwall of the blade, the tangent vector of the leading edge of the blade is... Tangent vector to the end wall meridian The dot product is zero, that is... ; Orthogonal design eliminates the acute-angled wedge-shaped region formed by the blade stacking line and the endwall, suppressing the migration of the horseshoe vortex pressure surface branch to the suction surface.
[0021] Furthermore, the process of establishing the end-wall parameterized model in S4 includes: The end-wall meridian is defined using Bézier curves or B-spline techniques; By adjusting the radial coordinates of the control points and axial coordinates A localized constriction channel is constructed in the region near the leading edge of the blade to accelerate the fluid first, suppress flow separation, and then allow for controlled diffusion. By adjusting the local curvature of the endwall, a pressure gradient opposite to the direction of the secondary flow driving force is constructed, thus hindering the migration of the transverse secondary flow.
[0022] Furthermore, the mechanism of localized contraction channels is as follows: according to the continuity equation, the mainstream is accelerated, the boundary layer shape factor H is reduced, the boundary layer is re-laminated or thinned, and the ability to resist subsequent adverse pressure gradients is enhanced, followed by controlled diffusion.
[0023] Furthermore, the process of establishing the endwall parameterization model in S4 also includes: by adjusting the local concavity and convexity curvature of the endwall, constructing a pressure gradient in the direction perpendicular to the streamlines that is opposite to the direction of the secondary flow driving force. To hinder the migration of lateral secondary flows.
[0024] Furthermore, in S4, based on computational fluid dynamics and global optimization algorithms, a collaborative optimization platform is constructed, and the process of setting the objective function includes: The set multi-objective functions include maximizing the stage multivariable efficiency, maximizing the surge margin, minimizing the total pressure loss coefficient, and constraining the residual swirl at the outlet of the return flow device, requiring the outlet airflow angle to be close to the axial direction in order to eliminate the intake distortion of the downstream impeller.
[0025] Furthermore, the optimization algorithm in S5 employs either a gradient-based adjoint method or a surrogate model-based global optimization algorithm. The global optimization algorithm based on the surrogate model includes: selecting sample points in the design space using Latin hypercube sampling, constructing the response surface using the Kriging model or artificial neural network, and searching for the Pareto optimal solution using a multi-objective genetic algorithm.
[0026] Furthermore, the objective function in S5 also includes constraints on the residual swirl at the outlet of the return flower, requiring the outlet airflow angle to be close to the axial direction in order to eliminate intake distortion on the downstream impeller.
[0027] In one specific embodiment, the following is included: Step 1: Establish the baseline aerodynamic boundary and the initial meridional channel (1) Required key boundary conditions: including: total pressure at the reflux inlet Total temperature Inlet airflow angle (Typically large deflection angles, such as 60°-70°) and design mass flow rate .
[0028] (2) Determine the basic geometric constraints of the return flow device according to the flow design requirements, including the inlet radius. Export radius The initial meridional channel consists of a crossover bend connecting to the diffuser outlet and a radial return channel. The axial width b and the number of blades Z are also considered.
[0029] Step 2: Construct a three-dimensional "aerodynamic orthogonal" blade parameterized model
[0030] (1) To address the horseshoe vortex accumulation problem in the acute angle region of traditional ruled surface design, a fully three-dimensional twisted blade is constructed using the three-dimensional inverse design concept. A fourth-order Bezier curve is used to define the arc distribution in the blade along the flow and span directions. Blade angle... The distribution adopts a "post-load" strategy, that is, setting a low rate of change of blade angle at the leading edge of the blade (0%-20% chord length). To reduce the leading edge load and avoid leading edge separation; increase the load in the rear part of the flow channel (30%-100% chord length) to complete the main diffusion and despinning tasks.
[0031] (2) In the mathematical model of blade generation, a geometrically orthogonal boundary condition is forcibly applied. Let the tangent vector of the blade leading edge curve be... The tangent vectors of the meridians of the wheel hub and the end wall of the wheel cover are respectively and At the leaf root and leaf tip, the constraint equation that the dot product must be satisfied is: and .
[0032] (3) Based on the above orthogonal superposition lines, the suction and pressure surfaces are thickened to form solid blades. This design eliminates the acute wedge region where the blade and endwall angle is less than 90°, and suppresses the strong entrainment of the horseshoe vortex pressure surface branch to the suction surface from the geometric source.
[0033] Step 3: In order to control boundary layer separation under high reverse pressure gradient, nonlinear fine-machining is performed on the meridional endwall of the return flow device (especially the hub side).
[0034] (1) Abandoning the traditional straight line or circular arc segment, a cubic B-spline curve with 5 control points is used to define the end wall meridian. Control points As a design variable for subsequent optimization.
[0035] (2) By adjusting the coordinates of the control points located near the leading edge of the blade, a local throat contraction zone is constructed in the inlet region of the flow channel. According to the continuity equation, this contraction reduces the mainstream velocity. Local increase, thereby reducing the boundary layer shape factor .
[0036] (3) After the boundary layer is thinned by flowing through the contraction zone, the cross-sectional area of the flow channel is adjusted by adjusting the subsequent control points. The diffusion rate gradually increases according to a predetermined rate. This "acceleration followed by diffusion" strategy significantly enhances the boundary layer's ability to resist strong downstream adverse pressure gradients.
[0037] (4) By fine-tuning the control points, the local curvature of the end wall is changed. A local concave curvature is introduced on the hub side to construct a pressure gradient pointing towards the end wall. This forms a "pressure barrier" to prevent the secondary flow from climbing along the longitudinal direction.
[0038] Step 4: Input the above parameterized model into the automated optimization process for global optimization.
[0039] (1) The Latin hypercube sampling (LHS) method was used to analyze the blade bending angle distribution coefficient and the coordinates of the endwall control points. Spatial sampling is performed on approximately 20-30 design variables, such as blade stacking angle, to generate 100-500 initial sample points.
[0040] (2) A structured grid was generated for each sample point, and numerical simulation was performed using the Reynolds-averaged Navier-Stokes (RANS) equation solver. The SST model was selected as the turbulence model to accurately capture the separated flow. The boundary conditions were set as follows: given total temperature and pressure and airflow angle distribution at the inlet, and given mass flow rate at the outlet.
[0041] (3) Based on the CFD calculation results, train the Kriging response surface model or radial basis function (RBF) neural network to establish the mathematical mapping relationship between geometric variables and aerodynamic performance, so as to replace the time-consuming CFD calculation.
[0042] (4) Define a multi-objective function : (Level Efficiency) (Surge margin) (Total pressure loss coefficient) (The outlet swirl angle is close to the axis). A multi-objective genetic algorithm is used to perform evolutionary search on the surrogate model, with the population size set at 50-200, and iterating for 30-100 generations to finally obtain the Pareto optimal front.
[0043] Step 5: Select the "knee" design from the Pareto front that balances efficiency and stability as the final solution, and perform full 3D unsteady CFD verification: Inspect the corner area of the reflux condenser to confirm that the volume of the separation bubble has been significantly reduced or eliminated. Inspect the leading edge of the blade to confirm that the horseshoe vortex structure is symmetrical and its intensity has decreased. The outlet flow field was checked to confirm that the airflow angle distribution was uniform and close to the axial direction, with no obvious low total pressure wake region, which met the intake air quality requirements of the downstream impeller.
[0044] Through the above steps, the final reflux rectifier design eliminates the sharp-angle dead zone in traditional designs and achieves efficient diffusion through active control of the end walls.
[0045] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0046] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for the coordinated design of orthogonal blades and streamlined endwalls in a high-pressure ratio centrifugal compressor, characterized in that, Includes the following steps: S1. Based on the overall design requirements of the compressor, determine the aerodynamic parameter boundary conditions and geometric constraints of the inlet and outlet of the reflux unit; S2. Establish a parameterized model of the blade, apply geometric orthogonal constraints at the intersection of the blade leading edge and the hub and cover, and generate a meridional aerodynamic orthogonal blades. S3. Establish a parameterized model of the end wall, use high-order curves to define the meridional profile of the hub and wheel cover, and introduce nonlinear control points to adjust the cross-sectional area distribution of the flow channel. S4. Construct a collaborative optimization platform and define the objective function; S5. Combining three-dimensional numerical calculation and optimization algorithms, the orthogonal parameters and endwall shape parameters of the blade are iteratively optimized until the objective function converges, and the optimal design scheme is obtained.
2. The method for co-designing orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor according to claim 1, characterized in that, The process of generating meridional aeroorthogonal blades in S2 includes: Abandoning ruled surface modeling, three-dimensional twisted surface modeling technology is adopted; The orthogonal constraint condition is set as follows: at the intersection of the leading edge and the endwall of the blade, the tangent vector of the leading edge of the blade is... Tangent vector to the end wall meridian The dot product is zero, that is... ; Orthogonal design eliminates the acute-angled wedge-shaped region formed by the blade stacking line and the endwall, suppressing the migration of the horseshoe vortex pressure surface branch to the suction surface.
3. The method for co-designing orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor according to claim 1, characterized in that, The process of establishing the endwall parametric model in S4 includes: The end-wall meridian is defined using Bézier curves or B-spline techniques; By adjusting the radial coordinates of the control points and axial coordinates A localized constriction channel is constructed in the region near the leading edge of the blade to accelerate the fluid first, suppress flow separation, and then allow for controlled diffusion. By adjusting the local curvature of the endwall, a pressure gradient opposite to the direction of the secondary flow driving force is constructed, thus hindering the migration of the transverse secondary flow.
4. The method for co-designing orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor according to claim 3, characterized in that, The mechanism of localized contraction channels is as follows: according to the continuity equation, the mainstream is accelerated, the boundary layer shape factor H is reduced, the boundary layer is re-laminated or thinned, and the ability to resist subsequent adverse pressure gradients is enhanced, followed by controlled diffusion.
5. The method for co-designing orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor according to claim 3, characterized in that, The process of establishing the endwall parameterization model in S4 also includes: by adjusting the local concavity and convexity curvature of the endwall, constructing a pressure gradient in the direction perpendicular to the streamlines that is opposite to the direction of the secondary flow driving force. To hinder the migration of lateral secondary flows.
6. The method for co-designing orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor according to claim 1, characterized in that, In S4, the process of constructing a collaborative optimization platform based on computational fluid dynamics and global optimization algorithms, and setting the objective function, includes: The set multi-objective functions include maximizing the stage multivariable efficiency, maximizing the surge margin, minimizing the total pressure loss coefficient, and constraining the residual swirl at the outlet of the return flow device, requiring the outlet airflow angle to be close to the axial direction in order to eliminate the intake distortion of the downstream impeller.
7. The method for co-designing orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor according to claim 1, characterized in that, The optimization algorithms in S5 employ either gradient-based adjoint methods or surrogate-based global optimization algorithms. The global optimization algorithm based on the surrogate model includes: selecting sample points in the design space using Latin hypercube sampling, constructing the response surface using the Kriging model or artificial neural network, and searching for the Pareto optimal solution using a multi-objective genetic algorithm.
8. The method for co-designing orthogonal blades and streamlined endwalls of a high-pressure ratio centrifugal compressor according to claim 1, characterized in that, The objective function in S5 also includes constraints on the residual swirl at the outlet of the return flower, requiring the outlet airflow angle to be close to the axial direction in order to eliminate intake distortion on the downstream impeller.