Design method of centrifugal fan blade and centrifugal fan

Abstract

The invention relates to the technical field of centrifugal fans, in particular to a centrifugal fan blade design method and a centrifugal fan. The method comprises the steps that contour line parameters of a main blade of the centrifugal fan are obtained, and multiple sets of initial splitter blades are generated based on the contour line parameters; the multiple sets of initial splitter blades are combined with the centrifugal fans respectively, aerodynamic performance evaluation is conducted on the combined centrifugal fans, the initial splitter blades corresponding to the centrifugal fan with the optimal aerodynamic performance are obtained, and the initial splitter blades serve as splitter blades to be combined with the centrifugal fans; the centrifugal fan comprises an impeller front disc, an impeller rear disc, a motor arranged between the impeller front disc and the impeller rear disc and a plurality of main blades, a flow collector is arranged at an air inlet of the impeller front disc, splitter blades are arranged among the main blades, and the splitter blades are designed based on the method. According to the method and the centrifugal fan, the flowing structure in the centrifugal fan is improved, the flowing loss and aerodynamic noise of the centrifugal fan are reduced, and the performance of the centrifugal fan is better.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal fans, and in particular to a design method for centrifugal fan blades and a centrifugal fan. Background Art

[0002] A centrifugal fan is a machine that relies on input mechanical energy to increase gas pressure and discharge gas. The internal conveying medium is general gas, and a large amount of loss and noise will be generated during operation. The loss is mainly flow loss, which includes friction loss and vortex loss. This is because the gas has viscosity. When the gas flows through the impeller flow channel of the centrifugal fan, it will be subject to blade friction resistance due to the viscosity, resulting in friction loss in the boundary layer; at the same time, when the gas is affected by the internal flow channel structure of the centrifugal fan, relative movement and flow resistance will also be generated between the internal flow layers of the gas, causing vortex loss and friction loss. In addition, the impeller, as a moving part of the centrifugal fan, is an important factor affecting the aerodynamic and noise performance of the centrifugal fan. Therefore, optimizing the impeller blades can effectively improve the working efficiency and noise of the centrifugal fan and improve the performance of the centrifugal fan. Summary of the invention

[0003] The embodiments of this specification provide a centrifugal fan blade design method and a centrifugal fan, aiming to solve one or more of the above-mentioned problems and other potential problems.

[0004] In order to achieve the above objectives, the following technical solutions are provided:

[0005] According to a first aspect of the present specification, a method for designing a centrifugal fan blade is provided, wherein the centrifugal fan comprises a plurality of main blades, and a splitter blade is arranged between adjacent main blades, and the method comprises:

[0006] Acquire the contour parameters of the main blade, and generate multiple groups of initial splitter blade parameters based on the contour parameters using the DOE algorithm; the initial splitter blade parameters include class function parameters and shape function parameters;

[0007] Constructing multiple groups of initial splitter blade models based on the multiple groups of initial splitter blade parameters;

[0008] A plurality of groups of the initial splitter blade models are respectively combined with the main blade model of the centrifugal fan for simulation, and the aerodynamic performance of each combined simulated centrifugal fan is evaluated to obtain the initial splitter blade model corresponding to the simulated centrifugal fan with the best aerodynamic performance, which is used as the final splitter blade model.

[0009] The centrifugal fan blade design method of the embodiment of this specification suppresses the generation of complex flow inside the centrifugal fan by adding splitter blades between the main blades of the centrifugal fan, reduces airflow separation and vortex, reduces gas flow loss, and reduces local excessive flow velocity, making the airflow more uniform, improving the working efficiency of the centrifugal fan and reducing noise. The splitter blade is simulated and designed by the CST parameterization method, and the simulation process is flexible and convenient. The aerodynamic performance of the centrifugal fan composed of the simulated splitter blade and the main blade is evaluated, and a centrifugal fan blade with good aerodynamic performance is obtained, thereby improving the working performance of the centrifugal fan.

[0010] In some embodiments, obtaining the contour parameters of the main blade, and generating multiple sets of initial splitter blade parameters using a DOE algorithm based on the contour parameters include:

[0011] The contour line of the main blade is obtained, and the contour line is parameterized using the CST parameterization method. The blade parameterization formula is as follows:

[0012]

[0013] ξ T =Δξ TE / c

[0014] ψ=x / c,ξ=z / c

[0015] Among them, ξ(ψ) represents the blade function, represents the class function, N1 and N2 determine the type of blade, S(ψ) represents the shape function, x represents the horizontal coordinate, z represents the vertical coordinate, c represents the blade chord length, Δξ TE Indicates the thickness of the blade trailing edge;

[0016] Determine class function parameters N1 and N2 of the initial splitter blade based on the class function parameters of the main blade;

[0017] The shape function S(ψ) of the initial splitter blade is represented by the Bernstein polynomial, and the formula is as follows:

[0018]

[0019] Among them, BP N represents the Bernstein polynomial, n represents the order of the Bernstein polynomial, A i represents the shape function parameters;

[0020] Use DOE algorithm to randomly generate multiple groups of shape function parameters A i , the shape function parameters A of the multiple groups of initial splitter blades are i They are respectively combined with the class function parameters of the initial splitter blades to generate multiple groups of initial splitter blade parameters.

[0021] In some embodiments, the chord length of the initial splitter blade is smaller than the chord length of the main blade.

[0022] In some embodiments, the method further includes: inputting the initial splitter blade model constructed with the initial splitter blade parameters into an approximate model to predict more initial splitter blade models.

[0023] In some embodiments, the method further includes: verifying the accuracy of the initial splitter blade model predicted by the approximate model through an accuracy verification formula.

[0024] In some embodiments, an aerodynamic performance evaluation is performed on each of the combined simulated centrifugal fans to obtain an initial splitter blade model corresponding to the simulated centrifugal fan with the best aerodynamic performance, including: using a multi-objective optimization algorithm to obtain the Pareto optimal solution set of the initial splitter blade model to obtain the initial splitter blade model corresponding to the centrifugal fan with the best aerodynamic performance.

[0025] In some embodiments, the multi-objective optimization algorithm uses the static pressure and static pressure efficiency of the centrifugal fan as optimization objectives.

[0026] In some embodiments, when a plurality of groups of the initial splitter blade models are respectively combined with the centrifugal fan model, the initial splitter blade is located in the center of the flow channel of the main blade of the centrifugal fan.

[0027] According to the second aspect of the present specification, a centrifugal fan is provided, comprising an impeller front disk and an impeller rear disk, a motor arranged between the impeller front disk and the impeller rear disk, and a plurality of main blades, the air inlet of the impeller front disk is provided with a collector, and splitter blades are provided between the main blades, and the splitter blades are designed based on the above-mentioned centrifugal fan blade design method.

[0028] In some embodiments, the splitter blade is disposed in the center of the flow channel between the main blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the embodiments of the present specification will become readily understood. In the accompanying drawings, several embodiments of the present specification are shown by way of example and not limitation.

[0030] Figure 1 A flow chart showing a method for designing centrifugal fan blades according to an embodiment of this specification;

[0031] Figure 2 A schematic diagram of a centrifugal fan according to an embodiment of this specification is shown;

[0032] Figure 3 Shows Figure 2Schematic diagram of the main blade and splitter blade.

[0033] 1- impeller front disc, 11- collector, 2- impeller rear disc, 3- motor, 4- main blade, 5- splitter blade.

[0034] In the various drawings, the same or corresponding reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present specification will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present specification are shown in the accompanying drawings, it should be understood that the present specification can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present specification more thorough and complete, and to fully convey the scope of the present specification to those skilled in the art.

[0036] The term "including" and its variations used in this document represent open inclusion, that is, "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one other embodiment". Terms such as "upper", "lower", "front", and "rear" indicating placement or positional relationships are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the principles of this specification, and do not indicate or imply that the referred elements must have a specific orientation, be constructed or operate in a specific orientation, and therefore should not be understood as limitations on this specification.

[0037] Taking a centrifugal fan without a volute as an example, when optimizing its impeller blades, diverter blades can be added between the main blades of the impeller to guide the internal airflow of the centrifugal fan, suppress the generation of complex gas flow inside the centrifugal fan, reduce the relative movement and flow resistance between the internal flow layers of the gas, and thus reduce flow losses and aerodynamic noise. Therefore, the centrifugal fan of the embodiment of this specification includes a plurality of main blades, and diverter blades are provided between adjacent main blades. In addition, in fluid mechanics, the shape of the gas flow channel can be improved by optimizing the shape of the diverter blades, reducing the sharp edges of the flow channel, etc., which can also further reduce the flow losses and aerodynamic noise of the gas. A design method for centrifugal fan blades of an embodiment of this specification is described in detail below in conjunction with the accompanying drawings. A blade design method for a centrifugal fan of an embodiment of this specification includes the following steps:

[0038] S1. Obtaining the contour parameters of the main blade, and generating multiple groups of initial splitter blade parameters using a DOE algorithm based on the contour parameters;

[0039] S3, constructing multiple groups of initial splitter blade models based on the multiple groups of initial splitter blade parameters;

[0040] S5. Combine multiple groups of the initial splitter blade models with the main blade model of the centrifugal fan respectively, perform aerodynamic performance evaluation on each of the combined simulated centrifugal fans to obtain the initial splitter blade model corresponding to the simulated centrifugal fan with the best aerodynamic performance, and use it as the final splitter blade model.

[0041] The splitter blade shape model of the embodiment of this specification is constructed based on the main blade shape of the centrifugal fan, reducing the amount of calculation in the splitter blade construction process. In step S1, the initial splitter blade parameters include class function parameters and shape function parameters. The class function and shape function in this specification are the class function and shape function representation methods in the CST method. The geometric shape of the initial splitter blade is represented by the CST parameterization method. The modeling process is relatively simple, and different blade shapes can be flexibly represented by adjusting the parameterization relationship. Among them, the class function is used in the CST method to control the type of geometric shape represented, and a set of parameters are used to define the basic outline of the shape to determine the overall characteristics and basic form of the shape; the shape function is used to further specify the shape defined by the class function, and a set of shape function parameters are used as design variables to accurately describe the geometric appearance of the shape. While keeping the basic outline of the shape unchanged, the shape is fine-tuned or optimized, and the local features of the shape such as curvature and thickness distribution are changed to achieve more refined shape control.

[0042] Specifically, step S1 includes:

[0043] S11, obtaining the contour line of the main blade, and parameterizing the contour line using the CST parameterization method. The blade parameterization formula is as follows:

[0044]

[0045] ξ T =Δξ TE / c

[0046] ψ=x / c,ξ=z / c

[0047] Among them, ξ(ψ) represents the blade function, represents the class function, N1 and N2 determine the type of blade, S(ψ) represents the shape function, x represents the horizontal coordinate, z represents the vertical coordinate, c represents the blade chord length, Δξ TE Indicates the thickness of the trailing edge of the blade. The values ​​of N1 and N2 determine the type of blade, for example, N1=0.5 and N2=1.0 for a round nose blade. The chord length of the initial splitter blade is smaller than the chord length of the main blade to prevent significant interference with the operation of the main blade. Preferably, the chord length of the initial splitter blade is 50% of the chord length of the main blade.

[0048] S13, determining the class function parameters N1 and N2 of the initial splitter blade based on the class function parameters of the main blade;

[0049] S15. The shape function S(ψ) of the initial splitter blade is expressed by a Bernstein polynomial, and the formula is as follows:

[0050]

[0051] Among them, BP N represents the Bernstein polynomial, n represents the order of the Bernstein polynomial, A i represents the shape function parameters;

[0052] First, in step S13, the class function parameters of the initial splitter blade are determined by the class function parameters of the main blade, that is, the class function parameters of the main blade are the same as the class function parameters of the initial splitter blade, so that the basic contour of the initial splitter blade and the main blade remains unchanged. Then, in step S15, multiple groups of the shape function parameters A are randomly generated by the DOE algorithm. i , and the initial splitter blade is more finely controlled in shape. The DOE algorithm generates variable data with small errors, and can obtain sufficient information through less variable data. The data has good universality and repeatability. The upper and lower contours of the blade can be parameterized to improve the shape representation accuracy, as shown in Table 1 and Table 2. At this time, the shape function parameters can be divided into blade upper contour parameters and blade lower contour parameters.

[0053] Table 1: Upper contour parameters

[0054]

[0055] Table 2: Lower contour parameters

[0056]

[0057] S17, the shape function parameters A of the multiple groups of initial splitter blades i They are respectively combined with the class function parameters of the initial splitter blades to generate multiple groups of initial splitter blade parameters.

[0058] After constructing multiple groups of initial splitter blade models based on the initial splitter blade parameters in step S3, more initial splitter blade models are obtained in order to reduce the amount of data processing. The existing initial splitter blade models constructed with the initial splitter blade parameters are input into the approximate model to predict more initial splitter blade models; wherein the approximate model is an existing model. In order to ensure the accuracy of the initial splitter blade models predicted by the approximate model, the initial splitter blade models predicted by the approximate model can be verified by the accuracy verification formula, and the initial splitter blade models with large shape differences from the main blade model are eliminated.

[0059] In step S5, a multi-objective optimization algorithm is used to obtain the Pareto optimal solution set of the initial splitter blade model, and an initial splitter blade model corresponding to the centrifugal fan with optimal aerodynamic performance is obtained. A multi-objective algorithm is an algorithm that can optimize multiple objective functions at the same time, such as a genetic algorithm, a particle swarm optimization algorithm, a simulated annealing algorithm, etc., to avoid the defects of single-objective optimization. The Pareto optimal solution set refers to a set of solutions that cannot be improved by any other solution in at least one objective among all feasible solutions, and at the same time do not make other objectives worse, that is, each solution in the Pareto optimal solution set is non-dominated, and there is no other solution that is better than it in all objectives. Aerodynamic performance evaluation refers to the calculation of relevant aerodynamic parameters of the centrifugal fan. In this specification, the static pressure and static pressure efficiency parameters of the centrifugal fan are mainly calculated and evaluated. That is, the multi-objective optimization algorithm of the embodiment of this specification takes the static pressure and static pressure efficiency of the centrifugal fan as the optimization target, finds a set of non-dominated solution sets that meet the requirements and their corresponding initial splitter blade models, optimizes the static pressure energy conversion efficiency of the centrifugal fan composed of the initial splitter blade and the main blade, and reduces the gas flow resistance of the centrifugal fan.

[0060] When multiple groups of the initial splitter blade models are combined with the centrifugal fan model, the initial splitter blade is located in the center of the flow channel of the main blade of the centrifugal fan. The separation vortex in the flow channel is effectively destroyed, complex flows such as secondary flows are reduced, and further work is performed on the circumferential outflowing gas, so that the fluid between the suction surface of the splitter blade and the pressure surface of the main blade can flow out smoothly, and the gas flow on both sides of the main blade is relatively balanced. Figure 2 , Figure 3As shown, a centrifugal fan disclosed in the embodiment of this specification includes an impeller front disk 1 and an impeller rear disk 2, a motor 3 and a plurality of main blades 4 arranged between the impeller front disk 1 and the impeller rear disk 2, the air inlet of the impeller front disk 1 is provided with a collector 11, and a splitter blade 5 is arranged between the main blades 4, and the splitter blade 5 is designed based on the above-mentioned centrifugal fan blade design method. The splitter blade 5 is arranged in the center of the flow channel between the main blades 4, improves the velocity distribution at the outlet of the impeller front disk 1 and the impeller rear disk 2, reduces the circumferential velocity at the outlet, increases the radial velocity, improves the flow structure when the gas is ejected from the outlet at a certain speed, and also improves the gas flow characteristics inside the centrifugal fan, improves the aerodynamic efficiency and reduces the gas flow loss, and at the same time reduces the noise and vibration generated by the centrifugal fan when it is working.

[0061] Although several specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of this specification. Certain features described in the context of separate embodiments may also be implemented in a single implementation in combination. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable sub-combination.

[0062] Although the subject matter has been described in language specific to structural features and / or methodological logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims.

[0063] The embodiments of the present specification have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for designing centrifugal fan blades, characterized in that: The centrifugal fan comprises a plurality of main blades, and splitter blades are arranged between adjacent main blades. The method comprises: Acquire the contour parameters of the main blade, and generate multiple groups of initial splitter blade parameters based on the contour parameters using the DOE algorithm; the initial splitter blade parameters include class function parameters and shape function parameters; Constructing multiple groups of initial splitter blade models based on the multiple groups of initial splitter blade parameters; A plurality of groups of the initial splitter blade models are respectively combined with the main blade model of the centrifugal fan for simulation, and the aerodynamic performance of each combined simulated centrifugal fan is evaluated to obtain the initial splitter blade model corresponding to the simulated centrifugal fan with the best aerodynamic performance, which is used as the final splitter blade model.

2. The method according to claim 1, characterized in that Acquiring the contour parameters of the main blade, and generating multiple groups of initial splitter blade parameters based on the contour parameters using a DOE algorithm, including: The contour line of the main blade is obtained, and the contour line is parameterized using the CST parameterization method. The blade parameterization formula is as follows: x T =Dx TE / c ψ=x / c,ξ=z / c Among them, ξ(ψ) represents the blade function, represents the class function, N1 and N2 determine the type of blade, S(ψ) represents the shape function, x represents the horizontal coordinate, z represents the vertical coordinate, c represents the blade chord length, Δξ TE Indicates the thickness of the blade trailing edge; Determine class function parameters N1 and N2 of the initial splitter blade based on the class function parameters of the main blade; The shape function S(ψ) of the initial splitter blade is represented by the Bernstein polynomial, and the formula is as follows: Among them, BP N represents the Bernstein polynomial, n represents the order of the Bernstein polynomial, A i represents the shape function parameters; Use DOE algorithm to randomly generate multiple groups of shape function parameters A i , the shape function parameters A of the multiple groups of initial splitter blades are i They are respectively combined with the class function parameters of the initial splitter blades to generate multiple groups of initial splitter blade parameters.

3. The method according to claim 2, characterized in that The chord length of the initial splitter blade is smaller than the chord length of the main blade.

4. The method according to claim 2, characterized in that: Also includes: The initial splitter blade model constructed with the initial splitter blade parameters is input into an approximate model to predict and obtain more initial splitter blade models.

5. The method according to claim 4, characterized in that Also includes: The accuracy of the initial splitter blade model predicted by the approximate model is verified by an accuracy verification formula.

6. The method according to claim 4, characterized in that Aerodynamic performance evaluation is performed on each combined simulated centrifugal fan to obtain an initial splitter blade model corresponding to the simulated centrifugal fan with optimal aerodynamic performance, including: using a multi-objective optimization algorithm to obtain the Pareto optimal solution set of the initial splitter blade model to obtain the initial splitter blade model corresponding to the centrifugal fan with optimal aerodynamic performance.

7. The method according to claim 6, characterized in that The multi-objective optimization algorithm takes the static pressure and static pressure efficiency of the centrifugal fan as optimization objectives.

8. The method according to claim 1, characterized in that When a plurality of groups of the initial splitter blade models are respectively combined with the centrifugal fan model, the initial splitter blade is located in the center of the flow channel of the main blade of the centrifugal fan.

9. A centrifugal fan, comprising an impeller front disk (1) and an impeller rear disk (2), a motor (3) and a plurality of main blades (4) arranged between the impeller front disk (1) and the impeller rear disk (2), wherein a collector (11) is arranged at an air inlet of the impeller front disk (1), characterized in that: Splitter blades (5) are provided between the main blades (4), and the splitter blades (5) are designed based on the method described in claim 1.

10. The centrifugal fan according to claim 9, characterized in that: The splitter blade is arranged in the center of the flow channel between the main blades.

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