CN115438441A - Centrifugal compressor impeller quasi-three-dimensional design method based on inverse design algorithm - Google Patents
Centrifugal compressor impeller quasi-three-dimensional design method based on inverse design algorithm Download PDFInfo
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Abstract
The application discloses a centrifugal compressor impeller quasi-three-dimensional design method based on an inverse design algorithm, wherein the method comprises the steps of carrying out preliminary guessing on the wall surface of an unknown flow channel through a ball thorn algorithm; generating a computational grid; input parameters are appointed to carry out quasi three-dimensional analysis on the meridian plane of the impeller so as to obtain the inner side target decompression distribution; calculating a difference between the current inside reduced pressure distribution and the target inside reduced pressure distribution; judging whether the current inner side reduced pressure distribution is close to the target inner side reduced pressure distribution or not, if so, stopping the deformation of the wall surface of the flow channel to obtain a target shape; if not, calculating the displacement of the wall surface of the flow channel, updating the geometric shape of the wall surface of the flow channel, and returning to the generation of the computational grid. The method has the advantages that the method for designing the impeller of the centrifugal compressor based on the inverse design algorithm improves meridian planes through inverse design of flow passage pressure reduction distribution so as to improve the performance of the impeller.
Description
Technical Field
The application relates to the field of impeller design, in particular to a centrifugal compressor impeller quasi-three-dimensional design method based on an inverse design algorithm.
Background
With the rapid development of the industries such as chemical industry, aerospace, navigation, military industry and the like, the demand of the centrifugal compressor is gradually increased. Therefore, the demand for the centrifugal compressor in terms of flow rate, pressure, efficiency, and development cost is also increasing.
Centrifugal compressors are widely used in various process flows for conveying air, various process gases or mixtures of gases and for increasing the pressure thereof. In a centrifugal compressor, a centrifugal force action given to gas by an impeller rotating at a high speed and a diffusion action given to gas in a diffusion passage cause a gas pressure to be increased. In the early days, the compressor was only suitable for low, medium pressure and large flow. Due to the development of chemical industry, the establishment of various large-scale plants and oil refineries, the centrifugal compressor is a key machine for compressing and conveying various gases in chemical production, and plays an extremely important role. How to improve the overall performance of the centrifugal compressor has important significance for saving energy, reducing emission and improving economic benefit.
Disclosure of Invention
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Some embodiments of the present application provide a method for designing a centrifugal compressor impeller in a quasi-three-dimensional manner based on an inverse design algorithm, to solve the technical problems mentioned in the above background, the method comprising: preliminarily guessing the wall surface of the unknown flow channel by a ball ratchet algorithm; generating a computational grid; specifying input parameters to perform quasi-three-dimensional analysis on the meridian plane of the impeller so as to obtain the inner side target reduced pressure distribution; calculating a difference between the current inboard reduced pressure distribution and the target inboard reduced pressure distribution; judging whether the current inner side reduced pressure distribution is close to the target inner side reduced pressure distribution or not, if so, stopping deformation of the wall surface of the flow channel to obtain a target shape; if not, calculating the displacement of the wall surface of the flow channel, updating the geometric shape of the wall surface of the flow channel, and returning to the generation of the computational grid.
Further, the preliminary guessing of the unknown flow channel wall surface through the ball ratchet algorithm includes: defining a two-dimensional flexible flow channel which is formed by a group of virtual balls and freely moves along a specified direction, and applying target reduced pressure distribution to the outer side of each flow channel wall surface, wherein the flow channel wall surface can deform to meet the target reduced pressure distribution at the inner side; assuming that the mass is uniformly distributed along the wall, the kinematic relationship of the flow channel wall is as follows:
in the above formula, F s Showing the force borne by the virtual ball on the ratchet column, delta P showing the difference between the target decompression distribution and the current decompression distribution, A showing the local stress area of the wall surface of the flow channel, theta showing the included angle between the stress direction of the virtual ball and the ratchet column, a s Represents acceleration, Δ y represents the displacement required to achieve the inboard target decompression profile;
the following equation is obtained by converting equation (1-2) based on the surface density of the flow path wall surface:
in the above formula, ρ represents the surface density of the flow path wall surface;
the new position of each virtual ball is given by the following formula:
in the above formula, x i Denotes the displacement in the x direction, y i Denotes the displacement in the y direction, Δ P i Representing the difference, theta, between the target and current reduced pressure distributions i The angle between the stress direction of the virtual ball and the ratchet column is shown.
Further, the input parameters include one or more of mass flow, rotational speed, number of blades, specific heat ratio, gas constant, inlet angle, inlet total temperature, and inlet total density.
Further, the input parameters may include one or more of a hub to shroud profile, an average blade shape, and a normal thickness distribution of the blades.
Further, in calculating the displacement of the flow path wall surface, the difference between the current inside pressure and the target inside pressure is applied to each virtual ball on the wall, and the displacement of each virtual ball along its backbone is obtained by the following formula:
upper typeIn, Δ s i Indicating the displacement of the wall surface of the flow passage; ρ represents the surface density of the flow channel wall surface; p r-target (i) Representing a target reduced pressure profile; p r (i) Indicating the current reduced pressure; theta.theta. i Representing the included angle between the stress direction of the virtual ball and the ratchet column;
in non-viscous flow, the stagnation pressure and the relative stagnation pressure of the stationary flow passage and the rotating flow passage are respectively constant, and then:
the reduced pressure is defined as follows:
the relative stagnation pressure is rewritten as:
in the above formula, P 0 Denotes the stagnation pressure, P denotes the static pressure, P 0r Denotes a relative stagnation pressure, pr denotes a reduced pressure, ρ denotes a wall surface density, W denotes a relative velocity, ω denotes an angular velocity, V denotes a fluid velocity, and R denotes an impeller radius.
Further, the pressure reduction at the inlet of the flow channel is used as an inlet boundary condition for the quasi-three-dimensional analysis, and the first virtual sphere on the wall surface of the flow channel is kept fixed.
Further, the centrifugal compressor impeller quasi-three-dimensional design method based on the inverse design algorithm further includes:
and (5) verifying the quasi-three-dimensional analysis by adopting three-dimensional numerical simulation.
Further, the verifying the quasi-three-dimensional analysis by using the three-dimensional numerical simulation includes: comparing the hub decompression distribution obtained by the quasi-three-dimensional analysis with a three-dimensional numerical simulation result; comparing the reduced pressure distribution on the shield calculated by the quasi-three-dimensional and three-dimensional numerical simulation and the experimental measurement results; the results of the quasi-three-dimensional analysis and the three-dimensional analysis of the reduced pressures on the hub and the shroud are compared.
The beneficial effect of this application lies in: the centrifugal compressor impeller quasi-three-dimensional design method based on the inverse design algorithm is provided, wherein the meridian plane is improved through the inverse design of flow passage pressure reduction distribution so as to improve the performance of the impeller.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, serve to provide a further understanding of the application and to enable other features, objects, and advantages of the application to be more apparent. The drawings and the description of the exemplary embodiments of the present application are provided for explaining the present application and do not constitute an undue limitation on the present application.
Further, throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic and that elements and elements are not necessarily drawn to scale.
In the drawings:
FIG. 1 is a schematic diagram of the main steps of a centrifugal compressor wheel quasi-three-dimensional design method based on an inverse design algorithm according to an embodiment of the present application;
FIG. 2 is a schematic view of a flow channel wall deformation based on a ball ratchet algorithm in a centrifugal compressor impeller quasi-three-dimensional design method based on an inverse design algorithm according to an embodiment of the present application;
FIG. 3 is a schematic representation of a pressure reduction distribution and flowpath shape for a first design in a centrifugal compressor wheel quasi-three dimensional design method based on an inverse design algorithm in accordance with an embodiment of the present application;
FIG. 4 is a schematic representation of a pressure reduction distribution and flowpath shape for a second design in a centrifugal compressor wheel quasi-three dimensional design method based on an inverse design algorithm in accordance with an embodiment of the present application;
FIG. 5 is a schematic representation of the pressure reduction distribution and flow channel shape for a third design in a method for a quasi-three-dimensional design of a centrifugal compressor wheel based on an inverse design algorithm according to an embodiment of the present application;
FIG. 6 is a schematic representation of a pressure reduction distribution and flow channel shape for a fourth design in a method for a quasi-three dimensional design of a centrifugal compressor wheel based on an inverse design algorithm in accordance with an embodiment of the present application;
FIG. 7 is a graph illustrating the efficiency of a fourth design in a method for quasi-three-dimensional design of a centrifugal compressor wheel based on an inverse design algorithm according to an embodiment of the present application.
Detailed Description
Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it is to be understood that the disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the disclosure are for illustration purposes only and are not intended to limit the scope of the disclosure.
It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings. The embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict.
It should be noted that the terms "first", "second", and the like in the present disclosure are only used for distinguishing different devices, modules or units, and are not used for limiting the order or interdependence relationship of the functions performed by the devices, modules or units.
It is noted that references to "a", "an", and "the" modifications in this disclosure are intended to be illustrative rather than limiting, and that those skilled in the art will recognize that "one or more" may be used unless the context clearly dictates otherwise.
The names of messages or information exchanged between devices in the embodiments of the present disclosure are for illustrative purposes only, and are not intended to limit the scope of the messages or information.
The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
For the convenience of understanding the technical solution of the present application, the following terms are used to explain the concepts of the present application:
target decompression: the desired pressure drop is achieved.
Currently, reducing the pressure: pressure drop at the current state.
The ball ratchet algorithm: which is used for the reverse design of centrifugal impellers. In this algorithm, the unknown flow path wall is made up of a set of virtual balls that move freely in a given direction, called a "ratchet". The difference between the target pressure distribution and the current pressure distribution of each modification step acts on each ball as a force that frequently deforms the wall surface. After the target shape is reached, the difference between the target pressure distribution and the current pressure distribution disappears, and finally the wall deformation is automatically stopped. The ball thorn algorithm converts the inverse design problem into a flow-solid phase interaction scheme of physical basic analysis, and is a method for rapid convergence.
Grid generation: in computational fluid dynamics, a set of discrete points regularly distributed in a flow field is called a grid, and a process of generating the nodes is called grid generation.
Quasi-three-dimensional analysis: to determine the average blade shape of a radial impeller, the initial model and various parameters are input to a solver. After the solution convergence, the pressure reduction distribution condition of the surfaces of the hub and the shield, the static pressure distribution condition of the radial plane, the pressure reduction distribution condition on the meridian plane and the relative speed distribution condition on the meridian plane can be obtained.
Mass flow rate: the mass of fluid per unit time that passes through the effective cross section of a closed pipe or open channel.
A diffuser: for reducing fluid flow rate and increasing hydrostatic pressure.
As shown in fig. 1, the method for designing a centrifugal compressor impeller in a quasi-three-dimensional manner based on an inverse design algorithm of the present application mainly includes the following steps:
s1: and carrying out preliminary guessing on the wall surface of the unknown flow channel by a ball ratchet algorithm.
S2: and generating a computational grid.
S3: and specifying input parameters to perform quasi three-dimensional analysis on the meridian plane of the impeller so as to obtain the inner side target reduced pressure distribution.
S4: a difference between the current inboard reduced pressure distribution and the target inboard reduced pressure distribution is calculated.
S5: judging whether the current inner side reduced pressure distribution is close to the target inner side reduced pressure distribution or not, if so, stopping deformation of the wall surface of the flow channel to obtain a target shape; if not, calculating the displacement of the wall surface of the flow channel, updating the geometric shape of the wall surface of the flow channel, and returning to the generation of the computational grid.
S6: and (3) verifying the quasi-three-dimensional analysis by adopting three-dimensional numerical simulation.
As a specific scheme, the step S1 specifically includes the following steps:
s11: defining a two-dimensional variable flow channel (also called as a flexible flow channel) formed by the way that the wall surfaces of the flow channel consist of a group of virtual balls and move freely along a specified direction, and applying target pressure reduction distribution on the outer side of each flow channel wall surface, wherein the flow channel wall surface can deform to meet the inner target pressure reduction distribution; assuming that the mass is uniformly distributed along the wall, the kinematic relationship of the flow channel wall is as follows:
in the above formula, F s Showing the force borne by the virtual ball on the ratchet column, delta P showing the difference between the target decompression distribution and the current decompression distribution, A showing the local stress area of the wall surface of the flow channel, theta showing the included angle between the stress direction of the virtual ball and the ratchet column, a s Represents the acceleration, Δ y represents the displacement required to reach the inside target decompression profile;
the fluid passes through the variable flow passage, causing a reduced pressure distribution to be applied to the inner side of the flow passage wall surface. If the target reduced-pressure distribution is applied to the outer side of each flow passage wall surface, the flexible wall surface is deformed to take a shape that satisfies the target reduced-pressure distribution on the inner side. Wherein the inner side target reduced pressure distribution is obtained by the quasi three-dimensional analysis of the meridian plane of the impeller. A force due to a difference between the target inside reduced pressure distribution and the current inside reduced pressure distribution at each point of the wall surface is applied to each virtual sphere and forces them to move. This pressure difference theoretically disappears when the target shape is reached.
Considering that the virtual balls move in the direction of the applied force, the adjacent virtual balls may collide with each other or move, which may interfere with the flow passage wall surface modification procedure. To avoid this problem, a ratchet concept is added to allow the virtual ball to move freely in a designated direction, as shown in fig. 2.
S12: the following equation is obtained by converting equation (1-2) based on the surface density of the flow path wall surface:
in the above formula, ρ represents the surface density of the flow path wall surface; Δ t is the interval at which the ball movement is performed in each shape modification step. The parameter delta t ^ 2/rho is an adjustment parameter of the convergence speed of the ball thorn algorithm. The lower the value of Δ t ^2/ρ, the slower the convergence speed. In fact, if Δ t ^2/ρ is too high, the design algorithm will diverge.
S13: the new position of each virtual ball is given by the following equation:
in the above formula, x i Denotes the displacement in the x direction, y i Denotes the displacement in the y direction, Δ P i Represents the difference between the target reduced pressure distribution and the current reduced pressure distribution, theta i The angle between the stress direction of the virtual ball and the ratchet column is shown.
In the meridional plane of the centrifugal compressor, the exit radius is fixed, not the horizontal length.
Specifically, in step S3, the input parameters include mass flow rate, rotational speed, number of blades, specific heat ratio, gas constant, inlet angle, total inlet temperature, total inlet density, hub-to-shroud profile, average blade shape, normal thickness distribution of blades, and the like. Wherein the mass flow rate, the rotational speed, the total inlet temperature and the total inlet density are experimentally measured at a design point defined at the inlet of the compressor.
Specifically, in step S4, the calculated pressure surface is typically solved by a partially convergent numerical solution of the flow equation. During the iterative design process, the force exerted on the flexible wall gradually disappears as the current reduced pressure distribution approaches the target reduced pressure distribution. Subsequent solutions to the flexible wall equation do not produce changes in the coordinates of the pipe surface.
Reduced pressure is sensed from the rotating flow channel wall, similar to the static pressure sensed from the stationary flow channel wall. The increase in boundary layer thickness along the wall of the rotating flow channel is therefore dependent on the reduced pressure gradient. As a specific solution, in calculating the displacement of the flow passage wall surface, the difference between the current inside pressure and the target inside pressure is applied to each virtual ball on the wall, and the displacement of each virtual ball along its spine is obtained by the following formula:
in the above formula,. DELTA.s i Indicating the displacement of the wall surface of the flow passage; ρ represents the surface density of the flow channel wall surface; p r-target (i) Representing a target reduced pressure profile; p r (i) Indicating a current reduced pressure; theta i The included angle between the stress direction of the virtual ball and the ratchet column is represented;
in the non-viscous flow, the stagnation pressure and the relative stagnation pressure of the stationary flow passage and the rotating flow passage are respectively constant, and then:
the reduced pressure is defined as follows:
the relative stagnation pressure is rewritten as:
in the above formula, P 0 Denotes the stagnation pressure, P denotes the static pressure, P 0r The pressure is expressed by the relative stagnation pressure, pr is reduced pressure, ρ is wall surface density, W is the relative velocity, ω is the angular velocity, V is the fluid velocity, and R is the impeller radius.
The stagnation pressure P is reduced by the above formula 0 Static pressure P and velocity V are respectively opposed to stagnation pressure P 0r Reduced pressure Pr and relative velocity W. The pressure felt from the rotating runner duct walls is the same as the static pressure felt from the stationary duct walls.
Since the starting point of each wall surface should be fixed during the design process, the inlet pressure reduction is used as the inlet boundary condition of the quasi-three-dimensional analysis code, and the first virtual sphere on the wall surface is kept fixed.
As a specific scheme, the quasi-three-dimensional analysis verified by three-dimensional numerical simulation comprises the following steps:
1) Comparing the hub decompression distribution obtained by the quasi-three-dimensional analysis with a three-dimensional numerical simulation result;
2) Comparing the pressure reduction distribution on the shield calculated by quasi-three-dimensional and three-dimensional numerical simulation and experimental measurement results;
3) The results of the quasi-three-dimensional analysis and the three-dimensional analysis of the reduced pressures on the hub and the shroud are compared.
After verifying the quasi-three-dimensional analysis results, the hub and shroud profiles of the impeller were obtained by incorporating the ball detent algorithm into the quasi-three-dimensional code and modifying the pressure relief distribution along the hub and shroud.
As in the design shown in fig. 3 (hereinafter design a), the corresponding shapes of the hub and shroud curved surfaces are obtained after modifying the current pressure relief profile. In design A, the additional backpressure gradient along the shroud curve is eliminated, but the inlet and outlet pressures are unchanged, i.e., keeping the area ratio fixed, it attempts to smooth it. Furthermore, as shown in fig. 3, the axial length of the modified impeller is reduced by 5%.
As in the design shown in fig. 4 (hereinafter referred to as design B), the outlet pressure slightly increases, resulting in an increase in the area ratio. Furthermore, the backpressure gradient along the shroud curved surface is lower than design a, which will reduce the degree of boundary layer thickening on the shroud curved surface. The angle of deflection from the inlet to the outlet is dependent on the distribution of the reduced pressure along the area around the hub and shroud curved surfaces. As shown in fig. 4, the correction pressure of the surrounding area is increased as compared with the original case.
As in the design shown in fig. 5 (hereinafter design C), which attempts to achieve a minimum adverse pressure gradient over the shroud curvature, the inlet and outlet pressures and the pressures of the areas around the hub and shroud curvatures remain constant, and thus the degree of deflection remains constant. In this case, the axial length of the modified impeller is reduced by 10%. The modification in design C will reduce the loss of boundary layer and will also reduce the effective area of the blade (radial plane area) and the average pressure level of the blade. It causes the vane to perform work on the fluid with less pressure and area of influence. Therefore, the pressure ratio of the impeller in design C is expected to decrease.
In designs A, B and C, the curved surface of the impeller hub and the curved surface of the shield are modified, so that the axial length of the impeller is changed. Separation along the shroud curved surface is easier than separation along the hub, and therefore, in order to improve the meridian plane geometry without changing the axial length, the hub curved surface geometry is kept fixed, and only the shroud curved surface geometry is changed. As a result, the distribution of the pressure relief automatically obtained along the curved surface of the hub may be uncontrolled.
To specify a target pressure relief profile along the shroud curved surface, the following two points should be considered:
a: the pressure exerted on the rotating field fluid is a reduced pressure. When the fluid flows out of the impeller rotating flow field, the pressure applied to the fluid changes from decompression to static pressure, i.e. the fluid faces 1/2 ρ r 2 ω 2 Leading to increased wake at the impeller exit. To overcome this sudden change in pressure, the fluid must be accelerated before it exits the impeller. The slope of the pressure relief profile on the curved surface of the hub is negative and the fluid is accelerated before exiting the impeller. Primarily with respect to the shroud curvature where the pressure reduction increases. The advantage of the pressure relief profile along the shroud curved surface is that the slope of the pressure relief at the impeller exit is negative and the fluid is accelerated before exiting the impeller. As in the design shown in fig. 6 (hereinafter design D), it abruptly decreases after increasing pressure drop along the shroud curved surface.
b: in the most efficient diffuser, the flowpath experiences a high pressure load in the first section and then flattens out at its end as shown by the target pressure reduction profile of design D.
Three-dimensional numerical simulation of design D shows that the design efficiency is improved by 0.6% compared with the original design. The increase in efficiency with respect to the normalized rotation speed is shown in fig. 7. In three-dimensional numerical simulation, the grid generation of the modified impeller is not different from the grid generation of the current impeller.
The invention uses a ball ratchet algorithm design program combined with a quasi-three-dimensional analysis code to design the hub curved surface and the shroud curved surface outline of the centrifugal compressor impeller. In order for the ball detent algorithm to converge within the rotation region, the difference between the target and current reduced pressure profiles should be applied in each shape modification step. The target pressure reduction distribution on the curved surface of the shield is high load at the first part of the flow passage, the middle part is mild, the last part is terminated with a negative value, and the design program converges to the outline of the curved surface of the shield, so that the efficiency of the compressor is improved by 0.6 percent.
The centrifugal compressor impeller quasi-three-dimensional design method based on the inverse design algorithm can be suitable for impeller design of centrifugal compressors, centrifugal fans, centrifugal pumps and the like.
The foregoing description is only exemplary of the preferred embodiments of the disclosure and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the invention in the embodiments of the present disclosure is not limited to the specific combination of the above-mentioned features, but also encompasses other embodiments in which any combination of the above-mentioned features or their equivalents is made without departing from the inventive concept as defined above. For example, the above features and (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure are mutually replaced to form the technical solution.
Claims (8)
1. A centrifugal compressor impeller quasi-three-dimensional design method based on an inverse design algorithm is characterized in that: the method comprises the following steps:
preliminarily guessing the wall surface of the unknown flow channel by a ball ratchet algorithm;
generating a computational grid;
input parameters are appointed to carry out quasi three-dimensional analysis on the meridian plane of the impeller so as to obtain the inner side target decompression distribution;
calculating a difference between the current inside reduced pressure distribution and the target inside reduced pressure distribution;
judging whether the current inner side reduced pressure distribution is close to the target inner side reduced pressure distribution or not, if so, stopping the deformation of the wall surface of the flow channel to obtain a target shape; if not, calculating the displacement of the wall surface of the flow channel, updating the geometric shape of the wall surface of the flow channel, and returning to the generation of the computational grid.
2. The inverse design algorithm-based quasi-three-dimensional design method for a centrifugal compressor impeller according to claim 1, wherein:
the preliminary guessing of the unknown flow channel wall surface through the ball ratchet algorithm comprises the following steps:
defining a two-dimensional flexible flow channel which is formed by a group of virtual balls and freely moves along a specified direction, and applying target reduced pressure distribution to the outer side of each flow channel wall surface, wherein the flow channel wall surface can deform to meet the target reduced pressure distribution at the inner side; assuming that the mass is uniformly distributed along the wall, the kinematic relationship of the flow channel wall is as follows:
in the above formula, F s Showing the force borne by the virtual ball on the ratchet column, delta P showing the difference between the target decompression distribution and the current decompression distribution, A showing the local stress area of the wall surface of the flow channel, theta showing the included angle between the stress direction of the virtual ball and the ratchet column, a s Represents acceleration, Δ y represents the displacement required to achieve the inboard target decompression profile;
the following equation is obtained by converting equation (1-2) based on the surface density of the flow path wall surface:
in the above formula, ρ represents the surface density of the flow path wall surface;
the new position of each virtual ball is given by the following formula:
in the above formula, x i Indicating a displacement in the x direction, y i Denotes the displacement in the y direction, Δ P i Represents the difference between the target reduced pressure distribution and the current reduced pressure distribution, theta i The included angle between the stress direction of the virtual ball and the ratchet column is shown.
3. The reverse design algorithm-based quasi-three-dimensional design method for a centrifugal compressor impeller of claim 1, wherein:
the input parameters include one or more of mass flow, rotational speed, number of blades, specific heat ratio, gas constant, inlet angle, total inlet temperature, and total inlet density.
4. The reverse design algorithm-based quasi-three-dimensional design method for a centrifugal compressor impeller according to claim 3, wherein:
the input parameters further include one or more of a hub to shroud profile, an average blade shape, and a normal thickness distribution of the blades.
5. The reverse design algorithm-based quasi-three-dimensional design method for a centrifugal compressor impeller according to claim 2, wherein:
in calculating the displacement of the wall surface of the flow path, the difference between the current inside pressure and the target inside pressure is applied to each virtual ball on the wall, and the displacement of each virtual ball along its spine is obtained by the following formula:
in the above formula,. DELTA.s i Indicating the displacement of the wall surface of the flow passage; ρ represents the surface density of the flow channel wall surface; p is r-target (i) Representing a target reduced pressure; p r (i) Indicating the current reduced pressure; theta.theta. i Representing the included angle between the stress direction of the virtual ball and the ratchet column;
in the non-viscous flow, the stagnation pressure and the relative stagnation pressure of the stationary flow passage and the rotating flow passage are respectively constant, and then:
the reduced pressure is defined as follows:
the relative stagnation pressure is rewritten as:
in the above formula, P 0 Representing stagnation pressure, P static pressure, P 0r Denotes a relative stagnation pressure, pr denotes a reduced pressure, ρ denotes a wall surface density, W denotes a relative velocity, ω denotes an angular velocity, V denotes a fluid velocity, and R denotes an impeller radius.
6. The inverse design algorithm-based quasi-three-dimensional design method for a centrifugal compressor impeller according to claim 5, wherein:
the pressure reduction at the inlet of the flow channel is used as an inlet boundary condition for the quasi-three-dimensional analysis, and the first virtual ball on the wall surface of the flow channel is kept fixed.
7. The reverse design algorithm-based quasi-three-dimensional design method for a centrifugal compressor impeller of claim 1, wherein:
the centrifugal compressor impeller quasi-three-dimensional design method based on the inverse design algorithm further comprises the following steps:
and (3) verifying the quasi-three-dimensional analysis by adopting three-dimensional numerical simulation.
8. The inverse design algorithm-based quasi-three-dimensional design method for a centrifugal compressor impeller according to claim 7, wherein:
the quasi three-dimensional analysis verified by adopting three-dimensional numerical simulation comprises the following steps:
comparing the hub decompression distribution obtained by the quasi-three-dimensional analysis with a three-dimensional numerical simulation result;
comparing the reduced pressure distribution on the shield calculated by the quasi-three-dimensional and three-dimensional numerical simulation and the experimental measurement results;
the results of the quasi-three-dimensional analysis and the three-dimensional analysis of the reduced pressures on the hub and the shroud are compared.
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| CN116502373B (en) * | 2023-06-30 | 2023-10-20 | 陕西空天信息技术有限公司 | Runner calculation grid generation method and device |
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