CN116541995B - Full-geometric space parameterized deformation method and system for multistage compressor - Google Patents
Full-geometric space parameterized deformation method and system for multistage compressor Download PDFInfo
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Abstract
The invention discloses a full-geometric space parameterized deformation method and a full-geometric space parameterized deformation system of a multistage compressor, wherein the method comprises the following steps: reading in full geometric data of the multistage compressor, wherein the full geometric data comprises at least one of the following components: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls; setting a control point on a target geometric molded line/surface as a direct control point, and determining the absolute coordinate of the control point according to the relative position coordinate of the control point on the target geometric molded line/surface; constructing a control body frame surrounding the whole geometry of the multistage compressor, and selecting a proper basis function; selecting different parameter coordinate solving methods aiming at various control body frames and basic functions, and solving parameter coordinates of a target geometry under various control body frame coordinate systems; and a variable dimension FFD or DFFD method is selected to control deformation of different target geometries, so that full-geometry space parameterized deformation of the compressor is realized. By adopting the method, abundant multidimensional deformation operation can be implemented on any geometric configuration of the compressor by adopting fewer control points.
Description
Technical Field
The invention relates to the technical field of compressor design, in particular to a full-geometric space parameterized deformation method and system of a multistage compressor.
Background
Currently, multistage compressor parameterization research is basically limited to runner profiles and blades, and joint parameterization methods and techniques of multiple rows of blades and other aerodynamic profiles (such as non-axisymmetric end walls) are mentioned. In the traditional method, each row of blades is separated and parameterized respectively, the relation of different row parameterization optimization processes is only information interaction on an optimization strategy (for example, control points are cooperatively moved by synchronizing the values of control variable values of each row of blades to form row linkage), but no direct relation exists on the parameterization method. The FFD and other grid deformation methods can further realize the integral parameterization of the blade channel profiles, but for multi-stage multi-row blades, control body frames of different blade channels still need to be reestablished, and the abrupt increase of control points limits the parameterization optimization application of the method in a multi-stage environment.
Disclosure of Invention
The embodiment of the invention provides a full-geometric space parameterized deformation method and a full-geometric space parameterized deformation system for a multistage compressor. The technical scheme is as follows:
in one aspect, a full geometric space parameterized deformation method of a multistage compressor is provided, the method comprising:
s1, reading in full-geometry data of a multi-stage compressor, wherein the full-geometry data comprises at least one of the following: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls;
s2, setting a control point on a target geometric molded line/surface as a direct operating point, and determining an absolute coordinate of the control point according to a relative position coordinate of the control point on the target geometric molded line/surface;
s3, constructing a control body frame which surrounds the whole geometry of the multistage compressor, and selecting a proper basis function;
s4, selecting different parameter coordinate solving methods aiming at various control body frames and basic functions, and solving parameter coordinates of a target geometry under various control body frame coordinate systems;
s5, a variable dimension FFD or DFFD method is selected to control deformation of different target geometries, and full-geometry space parameterized deformation of the air compressor is achieved.
Optionally, the S2 specifically includes:
s21, interpolating the discrete points of the target geometric molded line/molded surface to reconstruct the distribution of the discrete points of the target geometric molded line/molded surface;
s22, arc length normalization processing is carried out on the reconstructed target geometric line/profile discrete points, and the reconstructed target geometric line/profile is converted into a unit line segment/unit plane;
s23, giving the relative position coordinates of the control point on the unit line segment/unit plane, and determining the absolute coordinates of the control point according to the relative position coordinates.
Optionally, the step S22 specifically includes:
for discrete points of the profile, the profile of the original blade to be optimized is converted into a unit plane on a calculation domain through arc length normalization, so that the points of a physical domain and the calculation domain are mapped one by one, and the arc length normalization realizes normalization in two directions through formulas (1) and (2):
(1)
(2)
wherein ,；/>for discrete points on each section profile, < > for each section profile>The number of the sectional leaf profiles; />Is the total arc length of the radial jth cross-section She Xingxian; />Refers to the length of the chord length of the mth section on the radial jth section profile line; />Is the abscissa after the arc length normalization on the unit plane; />Is the ordinate of the unit plane after the arc length is normalized; />Is the length of the nth chord length on the radial ith section blade profile line; />Is the total arc length of the radial ith section blade profile;
and (3) for the discrete points of the molded lines, only normalizing one direction of the formula (1), and converting the molded lines into unit line segments of (0, 1).
Optionally, the step S3 specifically includes:
selecting a cuboid frame or inputting a frame with any shape by oneself, wherein the vertex grids of the cuboid frame are uniformly divided at equal intervals or are irregularly divided by self definition;
bernstein base is selected for runner and blade parameterization, B spline base is used for local refinement deformation, and different basis functions are used in combination to improve parameterization deformation effect.
Optionally, the S4 specifically includes:
judging whether the control body frame is a cuboid frame or not, if so, adopting a simplified method to solve, otherwise, adopting a Monte Carlo method to solve;
the simplified method solving includes:
the following formula (3) is an FFD deformation formula, N is a basis function, and the replacement of different basis functions N can be performed in the formula, so that different deformation control effects are realized;
(3)
wherein For controlling the number of segments of the frame divided in 3 directions, is->For controlling the vertex coordinates, N is the basis function, Q is the target geometrical real coordinates, +.>For the corresponding parameter coordinates of the target geometry in the frame, a mapping function of the physical space and the parameter space is established by the parameter coordinates>The weighted influence of all control vertexes on the geometrical deformation action of the target is represented, in the deformation process, parameter coordinates are kept unchanged, the control vertexes change, and the control vertexes finally act on the geometrical actual coordinates of the target to generate displacement;
for arbitrary meshing in 3 orthogonal directionsThe cuboid control body controls the vertex coordinates to meet the following relation:
(4)
the component of equation (3) in the x-direction can be written as:
(5)
the independence of the basis functions in 3 directions is known:，/>therefore, the formula (5) can be simplified as:
(6)
similarly, the y and z direction components of equation (3) are also respectively reduced to:
(7)
(8)
after simplification, the components of the FFD equation in 3 directions are converted into univariate tensor products by 3-variable tensor products, the space parameter coordinate solution is also reduced to curve parameter coordinate solution, the parameter coordinates in all directions are not coupled any more, independent solution is carried out, the tensor product loop nesting operation is greatly reduced, and the parameter coordinate solution speed is extremely high.
Optionally, the step S5 specifically includes:
determining a deformation object, if the deformation object is a runner molded line, embedding the upper and lower runner molded lines of the air compressor into a plane control frame by adopting a two-dimensional plane FFD (FFD) or DFFD (distributed Fourier transform) method, and giving or reversely solving the displacement of the vertex of the plane control frame through a direct operating point to generate a new frame and acting on the geometry of a target runner molded line to finish the runner deformation control;
in the case of a blade profile, an end wall profile, a three-dimensional space FFD or DFFD method is used, wherein if the FFD method is used, the displacement of the frame apex is givenGenerating a new frame, target set deformation +.>The method comprises the steps of carrying out a first treatment on the surface of the If the DFFD method is used, the control point shift +.>Reversely solving the frame vertex displacement->Until the last control point, a new frame is generated, the target geometry is deformed +.>。
Optionally, the method further comprises:
judging whether the deformed end wall is corrected, if so, carrying out boundary constraint and interpolation fairing treatment on the deformed end wall;
the boundary constraint includes: the boundary lines of the forced period are coincident and the two sides are tangent, and the boundary line of the rotor and the stator is replaced by a prototype symmetrical end wall line;
the interpolation fairing process includes: spline interpolation is carried out on the end wall molded surface along the axial direction and the tangential direction, grid encryption is carried out at the boundary, smoothness of boundary transition is guaranteed, and overall smoothness of the molded surface is improved.
In another aspect, a full geometry space parametric shape changing system for a multi-stage compressor is provided, the system comprising:
the reading-in module is used for reading in the full-geometry data of the multistage compressor, and the full-geometry data comprises at least one of the following: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls;
the setting module is used for setting a control point on the target geometric molded line/surface as a direct operating point, and determining the absolute coordinate of the control point according to the relative position coordinate of the control point on the target geometric molded line/surface;
the construction module is used for constructing a control body frame which surrounds the whole geometry of the multistage compressor and selecting a proper basis function;
the solving module is used for selecting different parameter coordinate solving methods aiming at various control body frames and basis functions and solving parameter coordinates of the target geometry under various control body frame coordinate systems;
and the deformation module is used for selecting a variable dimension FFD or DFFD method to perform deformation control on different target geometries so as to realize the full-geometry space parameterized deformation of the compressor.
In another aspect, an electronic device is provided, the electronic device including a processor and a memory, the memory storing at least one instruction, the at least one instruction loaded and executed by the processor to implement the full geometric space parameterized deformation method of a compressor.
In another aspect, a computer readable storage medium having stored therein at least one instruction loaded and executed by a processor to implement the full geometry spatial parameterization deformation method of a compressor as described above is provided.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
the invention can implement abundant multidimensional deformation operation on any geometric configuration of the compressor by adopting fewer control points, can easily realize conventional parameterization functions such as runner modification, blade sweep, blade profile change and the like, is also suitable for parameterization modeling of other aerodynamic configuration characteristics, and meets parameterization optimization requirements of most passive flow control technologies.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a full geometric space parameterized deformation method for a multistage compressor provided by an embodiment of the invention;
FIG. 2 is a flow chart of another method for full geometry space parameterization deformation of a multi-stage compressor according to an embodiment of the present invention;
fig. 3 is a non-uniformly divided rectangular DFFD control frame of a multi-stage compressor according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a method and a flow chart for parameterizing a full geometric surface DFFD of a compressor according to an embodiment of the present invention;
FIG. 5 is a schematic illustration of the connection of end wall profiles at grid boundaries provided by an embodiment of the present invention;
FIG. 6 is a schematic illustration of end wall profile fairing spline interpolation and boundary mesh encryption provided by an embodiment of the invention;
FIG. 7 is a schematic diagram of the application range of the full geometric space parameterized deformation method according to the embodiment of the invention;
FIG. 8 is a block diagram of a full geometry space parameterized deformation system for a multi-stage compressor in accordance with an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantages to be solved more apparent, the following detailed description will be given with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, an embodiment of the present invention provides a full geometric space parameterized deformation method of a multi-stage compressor, including:
s1, reading in full-geometry data of a multi-stage compressor, wherein the full-geometry data comprises at least one of the following: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls;
s2, setting a control point on a target geometric molded line/surface as a direct operating point, and determining an absolute coordinate of the control point according to a relative position coordinate of the control point on the target geometric molded line/surface;
s3, constructing a control body frame which surrounds the whole geometry of the multistage compressor, and selecting a proper basis function;
s4, selecting different parameter coordinate solving methods aiming at various control body frames and basic functions, and solving parameter coordinates of a target geometry under various control body frame coordinate systems;
s5, a variable dimension FFD or DFFD method is selected to control deformation of different target geometries, and full-geometry space parameterized deformation of the air compressor is achieved.
The following describes in detail a full geometric space parameterized deformation method of a multistage compressor according to an embodiment of the present invention with reference to fig. 2 to 7, as shown in fig. 2, including:
s1, reading in full-geometry data of a multi-stage compressor, wherein the full-geometry data comprises at least one of the following: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls;
specifically, the original compressor profile or profile geometry to be parameterized is sequentially input along the compressor flow direction, including the runner profile, each row of blade profiles (the corner transition profiles are included in the blade profiles), the end wall profiles, etc., or the geometric data of other compressor structures such as splitter/tandem blades, etc., can be input as required.
S2, setting a control point on a target geometric molded line/surface as a direct operating point, and determining an absolute coordinate of the control point according to a relative position coordinate of the control point on the target geometric molded line/surface;
optionally, the S2 specifically includes:
s21, interpolating the discrete points of the target geometric molded line/molded surface to reconstruct the distribution of the discrete points of the target geometric molded line/molded surface;
s22, arc length normalization processing is carried out on the reconstructed target geometric line/profile discrete points, and the reconstructed target geometric line/profile is converted into a unit line segment/unit plane;
s23, giving the relative position coordinates of the control point on the unit line segment/unit plane, and determining the absolute coordinates of the control point according to the relative position coordinates.
Optionally, the step S22 specifically includes:
for discrete points of the profile, the profile of the original blade to be optimized is converted into a unit plane on a calculation domain through arc length normalization, so that the points of a physical domain and the calculation domain are mapped one by one, and the arc length normalization realizes normalization in two directions through formulas (1) and (2):
(1)
(2)
wherein ,；/>for discrete points on each section profile, < > for each section profile>The number of the sectional leaf profiles; />Is the total arc length of the radial jth cross-section She Xingxian; />Refers to the length of the chord length of the mth section on the radial jth section profile line; />Is the abscissa after the arc length normalization on the unit plane; />Is the ordinate of the unit plane after the arc length is normalized; />Is the length of the nth chord length on the radial ith section blade profile line; />Is the total arc length of the radial ith section blade profile;
and (3) for the discrete points of the molded lines, only normalizing one direction of the formula (1), and converting the molded lines into unit line segments of (0, 1).
S3, constructing a control body frame which surrounds the whole geometry of the multistage compressor, and selecting a proper basis function;
optionally, the step S3 specifically includes:
selecting a cuboid frame or inputting a frame with any shape by oneself, wherein the vertex grids of the cuboid frame are uniformly divided at equal intervals or are irregularly divided by self definition;
as shown in fig. 3, a non-uniformly divided cuboid control frame is adopted to surround all geometric configurations of the 3-stage axial-flow diagonal flow combined compressor, so that the overall parameterization of the full geometric profile can be realized. Although the cuboid control body has lower geometric fit degree with the target, more control vertexes are wasted in the deformation space, partial parameterization efficiency is lost, and enough effective control vertexes can be provided through the encryption control vertex grid. The denser the control vertex mesh, the stronger the DFFD local deformability, and the more accurate the steering deformation. While encryption control vertices result in an increase in parameterized deformation computation that is negligible relative to parameterized optimization overall computation.
Bernstein base is selected for parameterization of flow channels and blades (after deformation, geometric smoothness is good, thickness change of the blades is small, occurrence probability of singular deformation is low), B spline base is used for local fine deformation (such as end wall parameterization, corner parameterization and the like), and different basis functions are used in combination to improve parameterization deformation effect.
S4, selecting different parameter coordinate solving methods aiming at various control body frames and basic functions, and solving parameter coordinates of a target geometry under various control body frame coordinate systems;
the step with the largest calculated amount and the longest time consumption in the parameterization process is to solve the parameter coordinates, especially for the full geometric configuration of the multistage compressor, the pneumatic molded surfaces are multiple and complex, and a great amount of time is often required to solve the parameter coordinates of all molded surfaces. In addition, the single-channel grids of different blade row fluid domains of the multistage compressor are not completely attached, staggering generally exists at the rotating-static interface, control bodies aiming at the geometric configuration of the multistage compressor are difficult to construct in the traditional FFD method, and generally a plurality of control bodies are required to be combined, so that the complexity of deformation operation is greatly increased. However, in the embodiment of the invention, the vertex of the control frame is not manipulated in the parameterization implementation process, the shape requirement on the control body is not high, and the control body which can surround the geometry of the compressor can meet the deformation requirement, so that the cuboid control frame can be practically applied to the full geometry of the multistage compressor. The parameter coordinates can be solved in a simplified manner by the following simplified method, and the calculation time of the parameter coordinates is not limited by application even for the full-geometric molded surface of the multi-stage compressor.
In the parameterized deformation process, the parameter coordinates are kept unchanged all the time, so that the parameter coordinates are only needed to be solved once in parameterized optimization iteration, and the subsequent iteration process can be directly read.
Optionally, the S4 specifically includes:
judging whether the control body frame is a cuboid frame or not, if so, adopting a simplified method to solve, otherwise, adopting a Monte Carlo method to solve;
the Monte Carlo method is simple in programming, difficult to diverge in solving, and suitable for different basis functions and control bodies with arbitrary shapes. However, the method is a random probability search method, and a large number of nested iterative computations are needed to be frequently performed, so that the overall computation time is long. The solution to the B-spline based FFD is computationally more intensive than the Bernstein based FFD, especially when the control volume frame vertices are dense, the computation time is even not acceptable in engineering. Therefore, the Monte Carlo method is more suitable for solving the geometrical parameter coordinates of the compressor with a smaller number of stages.
In order to realize the FFD parameterization of the full geometric configuration of the multistage compressor and reduce the solving time of parameter coordinates, the embodiment of the invention simplifies the FFD equation of the 3-variable tensor product.
The simplified method solving includes:
the following formula (3) is an FFD deformation formula, N is a basis function, and the replacement of different basis functions N can be performed in the formula, so that different deformation control effects are realized;
(3)
wherein For controlling the number of segments of the frame divided in 3 directions, is->For controlling the vertex coordinates, N is the basis function, Q is the target geometrical real coordinates, +.>For the corresponding parameter coordinates of the target geometry in the frame, a mapping function of the physical space and the parameter space is established by the parameter coordinates>The weighted influence of all control vertexes on the geometrical deformation action of the target is represented, in the deformation process, parameter coordinates are kept unchanged, the control vertexes change, and the control vertexes finally act on the geometrical actual coordinates of the target to generate displacement;
for arbitrary meshing in 3 orthogonal directionsThe cuboid control body controls the vertex coordinates to meet the following relation:
(4)
the component of equation (3) in the x-direction can be written as:
(5)
the independence of the basis functions in 3 directions is known:，/>therefore, the formula (5) can be simplified as:
(6)
similarly, the y and z direction components of equation (3) are also respectively reduced to:
(7)
（8）
after simplification, the components of the FFD equation in 3 directions are converted into univariate tensor products by 3-variable tensor products, the space parameter coordinate solution is also reduced to curve parameter coordinate solution, the parameter coordinates in all directions are not coupled any more, independent solution is carried out, the tensor product loop nesting operation is greatly reduced, and the parameter coordinate solution speed is extremely high.
In addition, although the simplified algorithm is still limited to a cuboid control body, the method is applicable to different basis functions, control peaks can be unevenly distributed, and flexibility of FFD deformation control is improved to a certain extent.
S5, a variable dimension FFD or DFFD method is selected to control deformation of different target geometries, and full-geometry space parameterized deformation of the air compressor is achieved.
Optionally, the step S5 specifically includes:
determining a deformation object, if the deformation object is a runner molded line, embedding the upper and lower runner molded lines of the air compressor into a plane control frame by adopting a two-dimensional plane FFD (FFD) or DFFD (distributed Fourier transform) method, and giving or reversely solving the displacement of the vertex of the plane control frame through a direct operating point to generate a new frame and acting on the geometry of a target runner molded line to finish the runner deformation control;
in the case of a blade profile, an end wall profile, a three-dimensional space FFD or DFFD method is used, wherein if the FFD method is used, the displacement of the frame apex is givenGenerating a new frame, target set deformation +.>The method comprises the steps of carrying out a first treatment on the surface of the If the DFFD method is used, the control point shift +.>Reversely solving the frame vertex displacement->Until the last control point, a new frame is generated, the target geometry is deformed +.>。
Specifically, the new geometric coordinates of the target after the deformation of the above formula (3) are:
(9)
the DFFD used in the embodiment of the present invention, as shown in fig. 4, still uses the FFD to control the body frame to perform space mapping and deformation, which absorbs the advantages of the FFD method, but the control point directly controlled is not the vertex of the body frame, but any point in the body space is controlled, and is generally selected as a point on the appearance of the controlled object. The displacement of the designated point on the surface of the target object is directly controlled, the fluctuation of each vertex of the control frame is reversely calculated, FFD operation is carried out on the control frame after the fluctuation, and the coordinates of other points of the target object are calculated, so that the overall geometric deformation is realized.
Equation (3) can be expressed as a matrix form q=np, where N is the row vector and is composed of the basis functions at the points assuming that the number of control points for direct manipulation is dMatrix, P is +.>A matrix. The coordinates of the control point of direct manipulation after the change can be expressed as:
(10)
the method is characterized by comprising the following steps:
(11)
wherein For the displacement of the direct-actuated control point>To control the displacement of the frame vertices.
Solving a least squares solution of the equation set (11)：
(12)
wherein A generalized inverse matrix of N, if N is a single-row non-zero matrix, < >>。
Least squares calculated by (12)SolutionThe minimum displacement amount of the direct control point to the designated position is satisfied, namely the vertex variation of the control frame is minimum. Substituting the changed control vertex coordinates into a deformation formula (9), and calculating coordinates of other points of the target geometry to complete the whole deformation process.
Optionally, the method further comprises:
judging whether the deformed end wall is corrected, if so, carrying out boundary constraint and interpolation fairing treatment on the deformed end wall;
the boundary constraint includes: the boundary lines of the forced period are coincident and the two sides are tangent, and the boundary line of the rotor and the stator is replaced by a prototype symmetrical end wall line;
the interpolation fairing process includes: spline interpolation is carried out on the end wall molded surface along the axial direction and the tangential direction, grid encryption is carried out at the boundary, smoothness of boundary transition is guaranteed, and overall smoothness of the molded surface is improved.
For the deformation of the non-axisymmetric end wall, the integral parameterization of the multi-stage compressor needs to solve the interface problem of CFD fluid domain grids of different blade channels. In the NUMECA software Autogrid module, the non-axisymmetric end wall mesh generation mode is to project the symmetric end wall surface mesh to the asymmetric surface, so that the continuity and smoothness of the deformed non-axisymmetric end wall surface mesh play a decisive role in the end wall surface mesh quality. Fig. 5 shows the connection of the axial flow diagonal flow combined compressor hub end wall at the periodic boundary and rotor-stator (RS) interface. The multistage compressor non-axisymmetric end wall grid with good quality and correct calculation needs to meet the following conditions:
1) The end wall is continuously smooth at the periodic boundaries;
2) The rotor-stator (RS) interface remains strictly unchanged, i.e. the end wall cannot deform at the RS interface.
Under the multistage environment, the control body shape and the control vertex distribution are limited, even if a control point on the end wall molded surface is directly controlled by adopting a DFFD method, deformation effects generated by nearby control points can be mutually influenced, the continuity and smoothness of the deformed end wall at the grid boundary are not easily strictly ensured, and certain shape difference can occur. Therefore, the boundary of the profile of the deformed end wall needs to be corrected, the boundary lines of the forced period are coincident and the two sides are tangent, and the RS boundary line is replaced by the prototype symmetrical end wall line. And then spline interpolation is carried out on the end wall molded surface along two directions, grid encryption is carried out at the boundary, the smoothness of boundary transition is ensured, and the overall light smoothness of the molded surface is improved, as shown in fig. 6.
The full-geometric space parameterized deformation method of the embodiment of the invention is applicable to any pneumatic configuration of the compressor, including but not limited to single-stage/multistage, axial-flow/diagonal-flow/radial-flow/combination and other various compressors; the method is also completely suitable for various complex geometric features and structures in the compressor, such as split-flow/serial blades, wing blades/winglets, vortex generators, non-axisymmetric end walls and the like; the same applies to other turbine geometry parametrization. The method can adopt fewer control points to implement rich multidimensional deformation operation on any geometric configuration of the compressor, can easily realize conventional parameterization functions such as runner modification, blade sweep, blade profile change and the like, is also suitable for parameterization modeling of other aerodynamic configuration characteristics, and meets parameterization optimization requirements of most passive flow control technologies. Fig. 7 illustrates the compressor geometry and flow control structure that can be covered by the parameterization method.
As shown in fig. 8, an embodiment of the present invention further provides a full geometric space parameterized deformation system of a multi-stage compressor, where the system includes:
the reading module 810 is configured to read in full-geometry data of the multi-stage compressor, where the full-geometry data includes at least one of the following: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls;
a setting module 820, configured to set a control point on a target geometric line/profile as a direct manipulation point, and determine an absolute coordinate of the control point according to a relative position coordinate of the control point on the target geometric line/profile;
a construction module 830 for constructing a control body frame surrounding the full geometry of the multi-stage compressor and selecting an appropriate basis function;
the solving module 840 is used for selecting different parameter coordinate solving methods for various control body frames and basis functions and solving parameter coordinates of the target geometry under various control body frame coordinate systems;
and the deformation module 850 is used for selecting a variable dimension FFD or DFFD method to perform deformation control on different target geometries so as to realize full-geometry space parameterized deformation of the compressor.
The functional structure of the full-geometric space parameterized deformation system of the multistage compressor provided by the embodiment of the invention corresponds to the full-geometric space parameterized deformation method of the multistage compressor provided by the embodiment of the invention, and is not repeated here.
Fig. 9 is a schematic structural diagram of an electronic device 900 according to an embodiment of the present invention, where the electronic device 900 may have relatively large differences due to different configurations or performances, and may include one or more processors (central processing units, CPU) 901 and one or more memories 902, where at least one instruction is stored in the memories 902, and the at least one instruction is loaded and executed by the processors 901 to implement the steps of the above-mentioned full geometric space parameterized deformation method of the compressor.
In an exemplary embodiment, a computer readable storage medium, e.g., a memory comprising instructions executable by a processor in a terminal to perform the full geometry spatial parameterization of the compressor described above, is also provided. For example, the computer readable storage medium may be ROM, random Access Memory (RAM), CD-ROM, magnetic tape, floppy disk, optical data storage device, etc.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and the storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (7)
1. A method for full geometric space parameterization deformation of a multistage compressor, the method comprising:
s1, reading in full-geometry data of a multi-stage compressor, wherein the full-geometry data comprises at least one of the following: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls;
s2, setting a control point on a target geometric molded line/surface as a direct operating point, and determining an absolute coordinate of the control point according to a relative position coordinate of the control point on the target geometric molded line/surface;
s3, constructing a control body frame which surrounds the whole geometry of the multistage compressor, and selecting a proper basis function;
s4, selecting different parameter coordinate solving methods aiming at various control body frames and basic functions, and solving parameter coordinates of a target geometry under various control body frame coordinate systems;
s5, selecting a variable dimension FFD or DFFD method to control deformation of different target geometries, so as to realize full-geometry space parameterized deformation of the compressor;
the step S3 specifically comprises the following steps:
selecting a cuboid frame or inputting a frame with any shape by oneself, wherein the vertex grids of the cuboid frame are uniformly divided at equal intervals or are irregularly divided by self definition;
selecting Bernstein base for parameterizing the runner and the blade, and B spline base for locally refining deformation, wherein different base functions are used in combination to improve parameterized deformation effect;
the step S4 specifically comprises the following steps:
judging whether the control body frame is a cuboid frame or not, if so, adopting a simplified method to solve, otherwise, adopting a Monte Carlo method to solve;
the simplified method solving includes:
the following formula (3) is an FFD deformation formula, N is a basis function, and the replacement of different basis functions N can be performed in the formula, so that different deformation control effects are realized;
（3）
wherein For controlling the number of segments of the frame divided in 3 directions, is->To control vertex coordinates>As a basis function +.>For the geometrical real coordinates of the object +.>For the corresponding parameter coordinates of the target geometry in the frame, a mapping function of the physical space and the parameter space is established by the parameter coordinates>The weighted influence of all control vertexes on the geometrical deformation action of the target is represented, in the deformation process, parameter coordinates are kept unchanged, the control vertexes change, and the control vertexes finally act on the geometrical actual coordinates of the target to generate displacement;
for arbitrary meshing in 3 orthogonal directionsThe cuboid control body controls the vertex coordinates to meet the following relation:
(4)
equation (3) is inThe component of the direction can be written as:
(5)
the independence of the basis functions in 3 directions is known:，/>therefore, the formula (5) can be simplified as:
(6)
in the same way, formula (3) isThe directional components are also respectively reduced to:
(7)
(8)
after simplification, the components of the FFD equation in 3 directions are converted into univariate tensor products by 3-variable tensor products, the space parameter coordinate solution is also reduced to curve parameter coordinate solution, the parameter coordinates in all directions are not coupled any more, and independent solution is carried out;
the step S5 specifically comprises the following steps:
determining a deformation object, if the deformation object is a runner molded line, embedding the upper and lower runner molded lines of the air compressor into a plane control frame by adopting a two-dimensional plane FFD (FFD) or DFFD (distributed Fourier transform) method, and giving or reversely solving the displacement of the vertex of the plane control frame through a direct operating point to generate a new frame and acting on the geometry of a target runner molded line to finish the runner deformation control;
in the case of a blade profile, an end wall profile, a three-dimensional space FFD or DFFD method is used, wherein if the FFD method is used, the displacement of the frame apex is givenGenerating a new frame, target set deformation +.>The method comprises the steps of carrying out a first treatment on the surface of the If the DFFD method is used, the control point shift +.>Reversely solving the frame vertex displacement->Generating a new frame until the last control point, and geometrically deforming the target。
2. The method according to claim 1, wherein S2 specifically comprises:
s21, interpolating the discrete points of the target geometric molded line/molded surface to reconstruct the distribution of the discrete points of the target geometric molded line/molded surface;
s22, arc length normalization processing is carried out on the reconstructed target geometric line/profile discrete points, and the reconstructed target geometric line/profile is converted into a unit line segment/unit plane;
s23, giving the relative position coordinates of the control point on the unit line segment/unit plane, and determining the absolute coordinates of the control point according to the relative position coordinates.
3. The method according to claim 2, wherein S22 specifically comprises:
for discrete points of the profile, the profile of the original blade to be optimized is converted into a unit plane on a calculation domain through arc length normalization, so that the points of a physical domain and the calculation domain are mapped one by one, and the arc length normalization realizes normalization in two directions through formulas (1) and (2):
(1)
（2）
wherein ,；/>for discrete points on each section profile, < > for each section profile>The number of the sectional leaf profiles; />Is the total arc length of the radial jth cross-section She Xingxian; />Refers to the length of the chord length of the mth section on the radial jth section profile line; />Is the abscissa after the arc length normalization on the unit plane; />Is the ordinate of the unit plane after the arc length is normalized; />Is the length of the nth chord length on the radial ith section blade profile line; />Is the total arc length of the radial ith section blade profile;
and (3) for the discrete points of the molded lines, only normalizing one direction of the formula (1), and converting the molded lines into unit line segments of (0, 1).
4. The method according to claim 1, wherein the method further comprises:
judging whether the deformed end wall is corrected, if so, carrying out boundary constraint and interpolation fairing treatment on the deformed end wall;
the boundary constraint includes: the boundary lines of the forced period are coincident and the two sides are tangent, and the boundary line of the rotor and the stator is replaced by a prototype symmetrical end wall line;
the interpolation fairing process includes: spline interpolation is carried out on the end wall molded surface along the axial direction and the tangential direction, grid encryption is carried out at the boundary, smoothness of boundary transition is guaranteed, and overall smoothness of the molded surface is improved.
5. A full geometry space parameterized deformation system for a multi-stage compressor, the system comprising:
the reading-in module is used for reading in the full-geometry data of the multistage compressor, and the full-geometry data comprises at least one of the following: geometric data of the runner molded lines, the molded surfaces of the blades of each row and the molded surfaces of the end walls;
the setting module is used for setting a control point on the target geometric molded line/surface as a direct operating point, and determining the absolute coordinate of the control point according to the relative position coordinate of the control point on the target geometric molded line/surface;
the construction module is used for constructing a control body frame which surrounds the whole geometry of the multistage compressor and selecting a proper basis function;
the solving module is used for selecting different parameter coordinate solving methods aiming at various control body frames and basis functions and solving parameter coordinates of the target geometry under various control body frame coordinate systems;
the deformation module is used for selecting a variable dimension FFD or DFFD method to perform deformation control on different target geometries so as to realize full-geometry space parameterized deformation of the compressor;
the construction module is specifically configured to:
selecting a cuboid frame or inputting a frame with any shape by oneself, wherein the vertex grids of the cuboid frame are uniformly divided at equal intervals or are irregularly divided by self definition;
selecting Bernstein base for parameterizing the runner and the blade, and B spline base for locally refining deformation, wherein different base functions are used in combination to improve parameterized deformation effect;
the solving module is specifically configured to:
judging whether the control body frame is a cuboid frame or not, if so, adopting a simplified method to solve, otherwise, adopting a Monte Carlo method to solve;
the simplified method solving includes:
the following formula (3) is an FFD deformation formula, N is a basis function, and the replacement of different basis functions N can be performed in the formula, so that different deformation control effects are realized;
（3）
wherein For controlling the number of segments of the frame divided in 3 directions, is->To control vertex coordinates>As a basis function +.>For the geometrical real coordinates of the object +.>For the corresponding parameter coordinates of the target geometry in the frame, establishing a physical space and parameters through the parameter coordinatesMapping function of space->The weighted influence of all control vertexes on the geometrical deformation action of the target is represented, in the deformation process, parameter coordinates are kept unchanged, the control vertexes change, and the control vertexes finally act on the geometrical actual coordinates of the target to generate displacement;
for arbitrary meshing in 3 orthogonal directionsThe cuboid control body controls the vertex coordinates to meet the following relation:
(4)
equation (3) is inThe component of the direction can be written as:
(5)
the independence of the basis functions in 3 directions is known:，/>therefore, the formula (5) can be simplified as:
(6)
in the same way, formula (3) isThe directional components are also respectively reduced to:
(7)
(8)
after simplification, the components of the FFD equation in 3 directions are converted into univariate tensor products by 3-variable tensor products, the space parameter coordinate solution is also reduced to curve parameter coordinate solution, the parameter coordinates in all directions are not coupled any more, and independent solution is carried out;
the deformation module is specifically used for:
determining a deformation object, if the deformation object is a runner molded line, embedding the upper and lower runner molded lines of the air compressor into a plane control frame by adopting a two-dimensional plane FFD (FFD) or DFFD (distributed Fourier transform) method, and giving or reversely solving the displacement of the vertex of the plane control frame through a direct operating point to generate a new frame and acting on the geometry of a target runner molded line to finish the runner deformation control;
in the case of a blade profile, an end wall profile, a three-dimensional space FFD or DFFD method is used, wherein if the FFD method is used, the displacement of the frame apex is givenGenerating a new frame, target set deformation +.>The method comprises the steps of carrying out a first treatment on the surface of the If the DFFD method is used, the control point shift +.>Reversely solving the frame vertex displacement->Generating a new frame until the last control point, and geometrically deforming the target。
6. An electronic device comprising a processor and a memory having at least one instruction stored therein, wherein the at least one instruction is loaded and executed by the processor to implement the full geometry space parameterized deformation method of the compressor of any of claims 1-4.
7. A computer readable storage medium having stored therein at least one instruction, wherein the at least one instruction is loaded and executed by a processor to implement the full geometry space parameterized deformation method of a compressor according to any one of claims 1-4.
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