Counter-rotating fan blade modulation method and device, counter-rotating fan and vehicle

Abstract

The invention discloses a contra-rotating fan blade modulation method and device, a contra-rotating fan and a vehicle. The method comprises the following steps: modulating phases of a plurality of blades of the counter-rotating fan to obtain a modulated phase angle of each blade; and the modulated phase angles of the multiple blades are symmetrically adjusted till the mass center of the fan blades coincides with the axis position of the fan blades. After the phase angles of the multiple blades in the circumferential direction of the fan blades of the contra-rotating fan are modulated, order noise and overall noise generated in the rotating process of the blades are reduced, and the mass centers of the fan blades return to zero by symmetrically adjusting the modulated phase angles of the multiple blades. While order noise in the axial flow counter-rotating fan is improved, the mass center of the fan blade is still kept on the rotating shaft, the mass center of the fan blade does not need to be adjusted through a balance weight mode and the like, cost is reduced, and the overall structure of the fan is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field related to fans, and in particular to a method, device, electronic equipment, storage medium, computer program product, counter-rotating fan and vehicle for modulating blades of a counter-rotating fan. Background Art

[0002] The counter-rotating fans of the prior art use blades that are evenly distributed at equal intervals. However, conventional usage scenarios require a higher rotation speed to achieve the requirements of large air volume and high air pressure. In scenarios with high rotation speed and large air volume, a particularly obvious "buzzing" harsh noise is very likely to occur, and the frequency of this noise is usually related to the rotation speed of the fan blades, which is called the fan's order noise. This phenomenon is usually caused by the decibel value of the noise at one or more frequencies far exceeding the average noise decibel value of other frequencies, which will produce a feeling that is easily perceived and uncomfortable, affecting people's psychological comfort after hearing the noise.

[0003] Therefore, in the prior art, the blades on the counter-rotating fan are designed to be distributed in an unequally spaced manner to reduce noise.

[0004] However, when the blades are unevenly distributed, the center of mass of the fan blades will change, causing the center of mass of the fan blades to not be on the rotation axis. The existing technology needs to adjust the center of mass of the fan blades by adding counterweights, etc., which increases costs and complicates the structure. Summary of the Invention

[0005] Based on this, it is necessary to provide a counter-rotating fan blade modulation method, device, electronic device, storage medium, computer program product, counter-rotating fan and vehicle to address the technical problem in the prior art that the center of mass of the counter-rotating fan blade is not on the rotating axis after modulation.

[0006] The present invention provides a method for modulating blades of a counter-rotating fan, comprising:

[0007] Modulating the phases of multiple blades of a counter-rotating fan until the multiple phase angle differences of each blade are unequal, thereby obtaining a modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles;

[0008] The modulated phase angles of the plurality of blades are symmetrically adjusted until the center of mass of the fan blade coincides with the axis position of the fan blade.

[0009] Furthermore, the symmetrically adjusting the modulated phase angles of the plurality of blades until the center of mass of the fan blade coincides with the axis position of the fan blade includes:

[0010] Selecting one or more blade groups from all the blades as blade groups to be adjusted, each blade group to be adjusted includes two axially symmetrical blades;

[0011] Determine the zeroing angle. In the same group of blades to be adjusted, increase the modulated phase angle of one blade by the zeroing angle to obtain the corresponding zeroing phase angle, reduce the modulated phase angle of another blade by the zeroing angle to obtain the corresponding zeroing phase angle, and the zeroing phase angles corresponding to the modulated phase angles of the remaining blades outside the blade group to be adjusted are the same as the modulated phase angle.

[0012] Further:

[0013] The modulation includes: calculating the equidistant phase angles of each blade in the circumferential direction of the counter-rotating fan under uniform distribution conditions, and calculating the modulated phase angle of the i-th blade based on the modulation angle as follows: α i ′=α i +θsinα i ; or α i ′=α i +θcosα i , where α i is the equidistant phase angle of the i-th blade, α i ′ is the modulated phase angle of the i-th blade after modulation, and θ is the modulation angle;

[0014] The determination of the zeroing angle includes: finding a zeroing angle that satisfies the optimization formula by the least square method, and calculating the phase angle of the modulated blade α i ′=α i +θsinα i In the case of , the optimization formula is: After calculating the modulation phase angle of the i-th blade, it is α i ′=α i +θcosα i In the case of , the optimization formula is: Wherein, N is the number of blades, α i " is the phase angle of the i-th blade after returning to zero.

[0015] Furthermore, the blades of the front blades of the counter-rotating fan are front blades, and the blades of the rear blades of the counter-rotating fan are rear blades, and the method further includes:

[0016] The front blades and the rear blades are modulated respectively based on different modulation angles, and after the centers of mass of the front blades and the rear blades are returned to the axis position, for each modulation angle, the order noise of the superimposed noise of all the front blades and all the rear blades is calculated, wherein the modulation angles include a front blade modulation angle for modulating the front blades and a rear blade modulation angle for modulating the rear blades;

[0017] The front blade modulation angle when the order noise is optimal is selected as the front blade optimal modulation angle, and the rear blade modulation angle is selected as the rear blade optimal modulation angle and outputted.

[0018] Furthermore, the calculating the order noise of the superimposed noise of all the front blades and all the rear blades includes:

[0019] Calculating a time domain superposition waveform of the relationship between the superposition noise and time;

[0020] transforming the time domain superposition waveform into a frequency domain waveform;

[0021] Order noise is extracted from the frequency domain waveform.

[0022] Furthermore, the calculating of the time domain superposition waveform of the relationship between the superposition noise and time of the noise generated by all the front blades and the noise generated by all the rear blades includes:

[0023] generating a front blade noise basic phase waveform related to the phase relationship of the noise generated by all the front blades and a rear blade noise basic phase waveform related to the phase relationship of the noise generated by all the rear blades;

[0024] At multiple sampling moments, the front blade rotation angle of the front blade rotated is determined according to the front blade speed, the rear blade rotation angle of the rear blade rotated is determined according to the rear blade speed, the waveform of the front blade noise basic phase waveform after being shifted in the rotation direction by the front blade rotation angle is used as the phase waveform of the front blade noise sampling moment, and the waveform of the rear blade noise basic phase waveform after being shifted in the rotation direction by the rear blade rotation angle is used as the phase waveform of the rear blade noise sampling moment;

[0025] Discretizing the phase waveform of the front blade noise at the sampling moment to obtain a front blade noise column vector, discretizing the phase waveform of the rear blade noise at the sampling moment to obtain a rear blade noise column vector, and taking the dot product of the front blade noise column vector and the rear blade noise column vector as the superimposed noise at the sampling moment;

[0026] A time domain superposition waveform regarding the relationship between the superposition noise and time is generated according to the superposition noise corresponding to all sampling moments.

[0027] The present invention provides a counter-rotating fan blade modulation device, comprising:

[0028] A phase angle modulation module is used to modulate the phases of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are unequal, thereby obtaining a modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles;

[0029] The zeroing module is used to symmetrically adjust the modulated phase angles of the plurality of blades until the center of mass of the fan blade coincides with the axis position of the fan blade.

[0030] The present invention provides an electronic device, comprising:

[0031] at least one processor; and,

[0032] a memory communicatively connected to at least one of the processors; wherein,

[0033] The memory stores instructions that can be executed by at least one of the processors. The instructions are executed by at least one of the processors to enable the at least one of the processors to perform the counter-rotating fan blade modulation method as described above.

[0034] The present invention provides a storage medium, which stores computer instructions. When a computer executes the computer instructions, it is used to execute all the steps of the counter-rotating fan blade modulation method as described above.

[0035] The present invention provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the above-mentioned counter-rotating fan blade bending method.

[0036] The present invention provides a counter-rotating fan, comprising a fan and blades arranged along the circumferential direction of the counter-rotating fan, wherein the blades are modulated using the counter-rotating fan blade modulation method as described above.

[0037] The present invention provides a vehicle comprising the counter-rotating fan as described above.

[0038] The present invention modulates the circumferential phase angles of multiple blades in a counter-rotating fan to reduce the order noise and overall noise generated during blade rotation. Symmetrical adjustment of the modulated phase angles of the blades returns the blade's center of mass to zero. While improving order noise in axial-flow counter-rotating fans, the present invention maintains the blade's center of mass on the axis of rotation, eliminating the need for counterweights or other methods to adjust the blade's center of mass, reducing costs and simplifying the fan's overall structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flowchart of a counter-rotating fan blade modulation method according to an embodiment of the present invention;

[0040] Figure 2 This is a flowchart of a counter-rotating fan blade modulation method according to another embodiment of the present invention;

[0041] Figure 3 A schematic diagram of a front blade according to an example of the present invention;

[0042] Figure 4 A schematic diagram of a rear blade according to an example of the present invention;

[0043] Figure 5 for Figure 3 Schematic diagram of the modulation of the front blade shown;

[0044] Figure 6 This is a flowchart of a counter-rotating fan blade modulation method according to a preferred embodiment of the present invention;

[0045] Figure 7 Schematic diagram of the one-dimensional waveform generated for a fan with nine unequally spaced blades;

[0046] Figure 8 Schematic diagram of the FFT results of the front and rear blade interference;

[0047] Figure 9 Based on Figure 7 The phase waveform of the front blade noise at a certain sampling moment is generated by the front blade noise basic phase waveform;

[0048] Figure 10 This is a workflow diagram for simulating noise from unequally spaced blades of an axial-flow counter-rotating fan according to the preferred embodiment of the present invention;

[0049] Figure 11 A schematic diagram of a counter-rotating fan blade modulation device according to an embodiment of the present invention;

[0050] Figure 12 The figure is a schematic diagram of the hardware structure of an electronic device of the present invention. DETAILED DESCRIPTION

[0051] The following further describes specific embodiments of the present invention with reference to the accompanying drawings. Like components are denoted by like reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inward" and "outward" refer to directions toward or away from the geometric center of a particular component, respectively.

[0052] like Figure 1 FIG. 1 is a flowchart of a counter-rotating fan blade modulation method according to an embodiment of the present invention, comprising:

[0053] Step S101, modulating the phases of multiple blades of a counter-rotating fan until the multiple phase angle differences of each blade are unequal, thereby obtaining a modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles;

[0054] Step S102: symmetrically adjust the modulated phase angles of the plurality of blades until the center of mass of the fan blade coincides with the axis position of the fan blade.

[0055] Specifically, the present invention can be applied to electronic devices with processing capabilities, such as computers.

[0056] The electronic device first executes step S101, modulating the phases of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are unequal, and obtaining the modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles.

[0057] Specifically, the modulation is to perform unequally spaced phase modulation on the multiple blades, which means that the phase angles of the blades are modulated so that they are unequally spaced. By modulating the equidistant phase angles of each blade, a modulated phase angle of each blade is obtained, thereby reducing order noise.

[0058] Modulation can be obtained by the designer based on experience or experimentation.

[0059] In some embodiments, modulating the phases of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are unequal to obtain the modulated phase angle of each blade includes:

[0060] The equidistant phase angles of each blade in the circumferential direction of the counter-rotating fan under uniform distribution conditions are calculated, and the equidistant phase angles of multiple blades are modulated based on the modulation angle to obtain the modulated phase angle of each blade.

[0061] Specifically, to solve the equidistant phase angle of each blade under uniform distribution conditions, the total number of blades is Then the phase of the i-th blade, that is, the equidistant phase angle of the i-th blade is: Where αi is the equidistant phase angle of the i-th blade.

[0062] Then, the equidistant phase angles of the plurality of blades are modulated based on the modulation angle to obtain a modulated phase angle of each blade.

[0063] In some embodiments, the modulated phase angle of each blade is obtained by adding the product of the trigonometric function value of the equidistant phase angle and the modulation angle.

[0064] Then, step S102 is executed to symmetrically adjust the modulated phase angles of the plurality of blades until the centroid of the fan blade coincides with the axis position of the fan blade.

[0065] After executing step S101, because the differences between the modulated phase angles are not completely equal, the center of mass of the modulated blade will not be at the axis center position and may be offset in the x-direction or the y-direction. Therefore, step S102 is executed to adjust the phase angles of some blades again so that the center of mass of the blades returns to zero. Here, zeroing the center of mass means that the center of mass returns to the axis center position.

[0066] The adjusted phase angle of each blade will be used in the blade design of the counter-rotating fan.

[0067] like Figure 3 and Figure 4 As shown, in some embodiments, a counter-rotating fan includes front blades 300 and rear blades 400, wherein the front blades 300 include a plurality of front blades 301, and the rear blades 400 include a plurality of rear blades 401. The phase angle of the blades is the angle between a selected reference point on the blade and a line connecting the center. The reference points of all blades are the same.

[0068] The present invention modulates the circumferential phase angles of multiple blades in a counter-rotating fan to reduce the order noise and overall noise generated during blade rotation. Symmetrical adjustment of the modulated phase angles of the blades returns the blade's center of mass to zero. While improving order noise in axial-flow counter-rotating fans, the present invention maintains the blade's center of mass on the axis of rotation, eliminating the need for counterweights or other methods to adjust the blade's center of mass, reducing costs and simplifying the fan's overall structure.

[0069] like Figure 2 FIG2 is a flowchart of a counter-rotating fan blade modulation method according to another embodiment of the present invention, comprising:

[0070] In step S201, the phases of the multiple blades of the counter-rotating fan are modulated until the multiple phase angle differences of each blade are unequal, thereby obtaining the modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles.

[0071] In one embodiment, the modulation includes: calculating the equidistant phase angles of each blade in the circumferential direction of the counter-rotating fan under uniform distribution conditions, and calculating the modulated phase angle of the i-th blade based on the modulation angle as follows: α i ′=α i +θsinα i ; or α i ′=α A +θcosα A , where α A is the equidistant phase angle of the i-th blade, α i ' is the modulated phase angle of the i-th blade after modulation, and θ is the modulation angle.

[0072] Step S202: selecting one or more blade groups from all the blades as blade groups to be adjusted, each blade group to be adjusted includes two axially symmetrical blades.

[0073] Step S203, determine the zeroing angle, in the same group of blades to be adjusted, increase the modulated phase angle of one blade by the zeroing angle to obtain the corresponding zeroing phase angle, reduce the modulated phase angle of another blade by the zeroing angle to obtain the corresponding zeroing phase angle, and the zeroing phase angles corresponding to the modulated phase angles of the remaining blades outside the blade group to be adjusted are the same as the modulated phase angle.

[0074] In one embodiment, the determining of the zeroing angle includes: finding a zeroing angle that satisfies the optimization formula by the least square method, and calculating the phase angle of the modulated blade i as α i ′=α i +θsinα i In the case of , the optimization formula is: After calculating the modulation phase angle of the i-th blade, it is α i ′=α i +θcosα i In the case of , the optimization formula is: Wherein, N is the number of blades, α i " is the phase angle of the i-th blade after returning to zero.

[0075] Specifically, first execute step S201 to modulate the phases of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are unequal, and obtain the modulated phase angle of each blade, where the phase angle difference is the difference between two adjacent modulated phase angles.

[0076] In some embodiments, if the number of blades is an odd number, one of the blades is selected as the reference blade, the equidistant phase angle of the reference blade is used as the modulated phase angle of the reference blade, and the remaining blades other than the reference blade are modulated; if the number of blades is an even number, all the blades are modulated.

[0077] Specifically, if the number of blades is an odd number, one of the blades is selected as the reference blade, and the reference blade is not modulated. Generally, a blade with a phase angle of 360° (i.e., 0°) can be selected as the reference blade. The equidistant phase angle of the reference blade does not need to be modulated. Therefore, the equidistant phase angle of the reference blade is used as the modulated phase angle of the reference blade, and then the remaining blades are modulated.

[0078] If the number of leaves is even, all leaves are modulated.

[0079] In one embodiment, the modulation includes: calculating the equidistant phase angles of each blade in the circumferential direction of the counter-rotating fan under uniform distribution conditions, and calculating the modulated phase angle of the i-th blade based on the modulation angle as follows: α i ′=α i +θsinα i ; or α i ′=α i +θcosα i , where α i is the equidistant phase angle of the i-th blade, α i ' is the modulated phase angle of the i-th blade after modulation, and θ is the modulation angle.

[0080] Specifically, the equidistant phase angle of each blade under uniform distribution conditions is solved, and the total number of blades is Then the phase of the i-th blade, that is, the equidistant phase angle of the i-th blade is: Among them, α i is the equidistant phase angle of the i-th blade.

[0081] Then, the modulated phase angle of the i-th blade is calculated based on the modulation angle: i ′=α i +θsinα i ; or α i ′=α i +θcosα i , where α i is the equidistant phase angle of the i-th blade, α i ' is the phase angle of the i-th blade after modulation, and θ is the modulation angle.

[0082] Specifically, θ is the modulation angle, and the trigonometric function can be a sinusoidal function or a cosine function. In engineering applications, the feasibility of engineering manufacturing must be considered on the one hand, while the air volume, air pressure, and noise performance of the counter-rotating fan must be balanced on the other. Therefore, the modulation angle should not be too large. The modulation angle of the front blades of an axial-flow counter-rotating fan is between 2° and 8°, and the modulation angle of the rear blades of the rear blades is between 1° and 5°.

[0083] When the sin function is used, the modulated phase angle of each blade after modulation is:

[0084] a i ′=a i +θsina i

[0085] When the cosine function is used, the modulated phase angle of each blade after modulation is:

[0086] α i ′=α i +θcosα i .

[0087] This embodiment significantly improves the order noise phenomenon in axial-flow counter-rotating fans by modulating the blade distribution, reducing the discomfort caused by a prominent single noise decibel value, and maximizing the reduction of blade order noise levels. Furthermore, this embodiment modulates the blades using specific trigonometric functions. Because the sin and cos functions can have positive or negative values ​​at different angles, it is possible to modulate the equidistant phase angles of the blades.

[0088] Then, step S202 is executed to select one or more blade groups from all the blades as blade groups to be adjusted, and each blade group to be adjusted includes two axially symmetrical blades.

[0089] Specifically, two groups of blades are generally selected as the blade groups to be adjusted. If only two blades are adjusted, the angle required to reset the center of gravity is relatively large, which generally causes blade overlap (that is, when viewed from the axial direction, the projections of the blades overlap). This design is not accurate enough or the cost is very high for mass production. If 6 blades are adjusted, for a fan with only 7 blades, after the center of gravity is reset and adjusted back, it is basically similar to the original uneven distribution of blades, with little change, and the unequal distribution for noise adjustment loses its meaning. Therefore, it is preferred to adjust 4 blades symmetrically, that is, two groups of blades to be adjusted.

[0090] Then, execute step S203 to determine the zeroing angle. In the same group of blades to be adjusted, the modulated phase angle of one blade is increased by the zeroing angle to obtain the corresponding zeroing phase angle, and the modulated phase angle of another blade is reduced by the zeroing angle to obtain the corresponding zeroing phase angle. The zeroing phase angles corresponding to the modulated phase angles of the remaining blades outside the blade group to be adjusted are the same as the modulated phase angle.

[0091] The two blades included in each set of blades to be adjusted have a modulated phase angle whose axis of symmetry is the x-axis or the y-axis, i.e., they are symmetrical about the x-axis or the y-axis. Within the same set of blades to be adjusted, the modulated phase angle of one blade is increased by a zeroing angle to obtain a zeroed phase angle, and the modulated phase angle of the other blade is decreased by a zeroing angle to obtain a zeroed phase angle, thereby simultaneously moving the modulated phase angles of the two blades within the same blade set closer to or further away from the axis of symmetry, thereby adjusting the fan blade center of mass (i.e., the center of gravity of the fan blade) so that the center of mass returns to zero.

[0092] In some embodiments, when N is an odd number, the Nth blade is selected as the reference blade, the 2nd and N-2th blades are selected as a group of blade groups, and the 3rd and N-3th blades are selected as a group of blade groups, wherein the modulated phase angles of the 2nd and 3rd blades are reduced by the zeroing angle to obtain the zeroing phase angle, and the modulated phase angles of the N-2th and N-3th blades are increased by the zeroing angle to obtain the zeroing phase angle.

[0093] In some embodiments, when N is an even number, the 2nd and N-1th blades are selected as a group of blade groups, and the 3rd and N-2th blades are selected as a group of blade groups, wherein the modulated phase angles of the 2nd and 3rd blades are reduced by the zeroing angle to obtain the zeroing phase angle, and the modulated phase angles of the N-1th and N-2th blades are increased by the zeroing angle to obtain the zeroing phase angle.

[0094] Specifically, a zeroing angle that returns the center of mass of the fan blade to zero is found by the least square method, and the modulated phase angles of the blades included in the blade group to be adjusted are adjusted based on the zeroing angle.

[0095] The least square method is an optimization algorithm, and the zeroing angle that makes the center of mass of the fan blade return to zero can be found by the least square method.

[0096] In one embodiment, the determining of the zeroing angle includes: finding a zeroing angle that satisfies the optimization formula by the least square method, and calculating the phase angle of the modulated blade i as α i ′=α i +θsinα i In the case of , the optimization formula is: After calculating the modulation phase angle of the i-th blade, it is α A ′=α A +θcosα A In the case of , the optimization formula is: Wherein, N is the number of blades, α A " is the phase angle of the i-th blade after returning to zero.

[0097] Specifically, for the phase angle modulated by the sin function, the center of mass will change in the x direction. Therefore, the For the phase angle modulated by cosine function, the center of mass will change in the y direction, so the Seek the best.

[0098] The least squares method is used to find the zeroing angle β that meets the optimization conditions, that is, the modulated phase angle of the blades of the blade group to be adjusted is adjusted based on the zeroing angle β to obtain the zeroing phase angle, and the zeroing phase angles of the remaining blades are kept as the modulated phase angles, and the zeroing angle that minimizes the sum of the sin values ​​or cos values ​​of the zeroing phase angles of all blades is found.

[0099] The modulated phase angle of the blades of the blade group to be adjusted is adjusted using the zeroing angle β that meets the optimization conditions to obtain the zeroing phase angle, and the zeroing phase angles of the remaining blades remain at the modulated phase angle, so that the center of mass of the fan blades including blades with unequal phase angles returns to the axis center.

[0100] This embodiment uses an optimization algorithm to quickly determine the zeroing angle, thereby achieving an uneven distribution of blade spacing while maintaining the center of mass of the fan blade on the rotation axis.

[0101] like Figure 3 As shown, when N=9, the modulation angle θ=6°, and the zeroing angle β=7.32°, the phase angles of each front blade 301 after zeroing are: 43.86°, 78.59°, 117.88°, 162.05°, 197.95°, 242.12°, 281.41°, 316.14° and 360° respectively.

[0102] like Figure 5 Shown Figure 3 Modulation diagram of the front blade shown, Figure 5 Point 1 is the modulated phase angle of the first front blade, point 2 is the modulated phase angle of the second front blade, point 3 is the modulated phase angle of the third front blade, point 4 is the modulated phase angle of the fourth front blade, point 5 is the modulated phase angle of the fifth front blade, point 6 is the modulated phase angle of the sixth front blade, point 7 is the modulated phase angle of the seventh front blade, point 8 is the modulated phase angle of the eighth front blade, and point 9 is the modulated phase angle of the ninth front blade. The second and seventh front blades symmetrical about the x-axis are selected as a blade group, and the third and sixth front blades symmetrical about the x-axis are selected as a blade group. The second front blade is adjusted based on the zeroing angle β to obtain the phase angle after zeroing, corresponding to point 2'; the seventh front blade is adjusted based on the zeroing angle β to obtain the phase angle after zeroing, corresponding to point 7'; the third front blade is adjusted based on the zeroing angle β to obtain the phase angle after zeroing, corresponding to point 3'; the sixth front blade is adjusted based on the zeroing angle β to obtain the phase angle after zeroing, corresponding to point 6'.

[0103] like Figure 4As shown, when N=7, the modulation angle θ=3.5°, and the zeroing angle β=3.475°, the phase angles of the rear blades 401 after zeroing are 50.69°, 102.79°, 155.80°, 204.20°, 257.21°, 309.31°, and 360°, respectively.

[0104] The number of blades N is generally 7-11. For the front blades, θ is 2-8°, and for the rear blades, θ is 1-5°.

[0105] This embodiment achieves uneven distribution of blades by increasing the product of the trigonometric function value of the equidistant phase angle and the modulation angle for each blade. Simultaneously, a least squares method is used to effectively find a suitable zeroing angle. Based on the adjustment of the zeroing angle, the centroid of the fan blades is maintained on the axis of the rotation axis. Thus, while maintaining the centroid of the fan blades on the rotation axis, the fan blades are unevenly distributed, achieving a low-noise counter-rotating fan design.

[0106] In one embodiment, the blades of the front blades of the counter-rotating fan are front blades, and the blades of the rear blades of the counter-rotating fan are rear blades, and the method further includes:

[0107] The front blades and the rear blades are modulated respectively based on different modulation angles, and after the centers of mass of the front blades and the rear blades are returned to the axis position, for each modulation angle, the order noise of the superimposed noise of all the front blades and all the rear blades is calculated, wherein the modulation angles include a front blade modulation angle for modulating the front blades and a rear blade modulation angle for modulating the rear blades;

[0108] The front blade modulation angle when the order noise is optimal is selected as the front blade optimal modulation angle, and the rear blade modulation angle is selected as the rear blade optimal modulation angle and outputted.

[0109] Specifically, the counter-rotating fan includes front blades and rear blades that are coaxial and rotate relatively to each other, the blades of the front blades are front blades, and the blades of the rear blades are rear blades.

[0110] The method of this embodiment also includes optimizing the optimal modulation of the front and rear blades and performing noise simulation on the unequally spaced blades.

[0111] Specifically, step S101 to step S102, or step S201 to step S203, are performed to modulate the front blades and the rear blades based on different modulation angles, and after the center of mass of the front blades and the rear blades are returned to the axis position, for each modulation angle, the order noise of the superimposed noise of all the front blades and all the rear blades is calculated. Wherein, the superimposed noise is obtained by superimposing the noise generated by all the front blades and the noise generated by all the rear blades.

[0112] Then, the front blade modulation angle when the order noise is optimal is selected as the front blade optimal modulation angle, and the rear blade modulation angle is selected as the rear blade optimal modulation angle.

[0113] After obtaining the optimal modulation angle of the front blade and the optimal modulation angle of the rear blade, the phase angle after returning to zero of each front blade under the optimal modulation angle of the front blade can be used as the phase angle of the front blade, and the phase angle after returning to zero of each rear blade under the optimal modulation angle of the rear blade can be used as the phase angle of the rear blade.

[0114] Among them, multiple different modulation angles can be set, and the order noise of different modulation angles can be calculated respectively, and then the front blade modulation angle when the order noise is optimal is selected as the optimal modulation angle of the front blade, and the rear blade modulation angle is selected as the optimal modulation angle of the rear blade.

[0115] Multiple order noise optimization steps can also be performed. In each order noise optimization step, the front blades and the rear blades are modulated separately based on different modulation angles. After the center of mass of the front blades and the rear blades are returned to the axis position, for each modulation angle, the order noise of the superimposed noise of the noise generated by all the front blades and the noise generated by all the rear blades is calculated. The modulation angle includes a front blade modulation angle for modulating the front blades and a rear blade modulation angle for modulating the rear blades. If the order noise is the smallest, the front blade modulation angle of the order noise optimization step is used as the optimal modulation angle of the front blades, and the rear blade modulation angle is used as the optimal modulation angle of the rear blades. Otherwise, the modulation angle is modified and the order noise optimization step is performed again.

[0116] Among them, when the data is small, the Design of Experiments (DOE) strategy is adopted to select the result with the smallest order noise to output the optimal modulation angle of the front blade and the optimal modulation angle of the rear blade; when the data is large, the Pareto optimal strategy is adopted to extract the result with the smaller order noise to output the optimal modulation angle of the front blade and the optimal modulation angle of the rear blade.

[0117] like Figure 6As shown, the working flow diagram of a counter-rotating fan blade modulation method according to the preferred embodiment of the present invention includes:

[0118] Step S601, determining the front blade modulation angle, calculating the blade equidistant phase angle of each front blade based on the front blade modulation angle, performing blade modulation on the blade level phase angle of the front blade, and then returning the fan blade centroid to zero for the front blade;

[0119] Step S602, determining the rear blade modulation angle, calculating the blade equidistant phase angle of each rear blade based on the rear blade modulation angle, performing blade modulation on the blade level phase angle of the rear blade, and then returning the fan blade centroid to zero for the rear blade;

[0120] Step S603: If the order noise is Pareto optimal, execute step S604; otherwise, execute steps S601 and S602 again;

[0121] Step S604: outputting the modulation strategies of the front and rear blades.

[0122] This embodiment implements an optimization strategy for modulating the optimal unequally spaced blade distribution of a counter-rotating fan, thereby maximally reducing the order noise of the counter-rotating fan.

[0123] In one embodiment, the calculating the order noise of the superimposed noise of all the front blades and all the rear blades includes:

[0124] Calculating a time domain superposition waveform of the relationship between the superposition noise and time;

[0125] transforming the time domain superposition waveform into a frequency domain waveform;

[0126] Order noise is extracted from the frequency domain waveform.

[0127] Specifically, calculating the order noise of the superimposed noise of the noise generated by all the front blades and the noise generated by all the rear blades specifically includes:

[0128] Execute steps S101 to S102, or steps S201 to S203 to generate the phase angle of the front blade of the front fan blade after returning to zero as the phase of the front blade on the circumference, and generate the phase angle of the rear blade of the rear fan blade after returning to zero as the phase of the rear blade on the circumference.

[0129] Based on the phase of the front blades and the phase of the rear blades on the circumference, a time domain superposition waveform of the superposition noise and time relationship of the noise generated by all the front blades and the noise generated by all the rear blades is calculated.

[0130] The time domain superposition waveform is converted into a frequency domain waveform (frequency domain signal) through the fast Fourier transform FFT, and the order of focus is extracted. For example, for a seven-blade fan, the seventh order noise is the largest, so the order of focus is the seventh order; for a nine-blade fan, the ninth order noise is the largest, so the order of focus is the ninth order. Record the order noise results, such as Figure 8 is the FFT result of the front and rear blade interference, where the corresponding peak frequencies are the frequencies of each order, and the amplitude corresponding to the peak is the simulated energy value of the order noise.

[0131] The smallest order noise means that the amplitude of the focused order is the smallest, and the smaller order noise means that the amplitude of the focused order is the smallest.

[0132] This embodiment performs frequency domain transformation on the time domain superimposed waveform to accurately extract the order noise.

[0133] In one embodiment, the calculating of the time domain superposition waveform of the relationship between the superposition noise of the noise generated by all the front blades and the noise generated by all the rear blades and time includes:

[0134] generating a front blade noise basic phase waveform related to the phase relationship of the noise generated by all the front blades and a rear blade noise basic phase waveform related to the phase relationship of the noise generated by all the rear blades;

[0135] At multiple sampling moments, the front blade rotation angle of the front blade rotated is determined according to the front blade speed, the rear blade rotation angle of the rear blade rotated is determined according to the rear blade speed, the waveform of the front blade noise basic phase waveform after being shifted in the rotation direction by the front blade rotation angle is used as the phase waveform of the front blade noise sampling moment, and the waveform of the rear blade noise basic phase waveform after being shifted in the rotation direction by the rear blade rotation angle is used as the phase waveform of the rear blade noise sampling moment;

[0136] Discretizing the phase waveform of the front blade noise at the sampling moment to obtain a front blade noise column vector, discretizing the phase waveform of the rear blade noise at the sampling moment to obtain a rear blade noise column vector, and taking the dot product of the front blade noise column vector and the rear blade noise column vector as the superimposed noise at the sampling moment;

[0137] A time domain superposition waveform regarding the relationship between the superposition noise and time is generated according to the superposition noise corresponding to all sampling moments.

[0138] Specifically, firstly, a front blade noise basic phase waveform regarding the noise generated by all the front blades and the phase relationship and a rear blade noise basic phase waveform regarding the noise generated by all the rear blades and the phase relationship are generated respectively.

[0139] In some embodiments, the step of respectively generating a front blade noise basic phase waveform related to the phase relationship of the noise generated by all the front blades and a rear blade noise basic phase waveform related to the phase relationship of the noise generated by all the rear blades comprises:

[0140] Setting the noise contribution amplitude of the phase angle position after the return to zero of each front blade to A, and the noise contribution amplitude of the remaining positions to B, with A greater than B, setting a gradual transition area with the phase angle position after the return to zero of each front blade as the center, and generating a front blade noise basic phase waveform regarding the relationship between the noise and phase generated by all the front blades;

[0141] The noise contribution amplitude of the phase angle position after returning to zero of each rear blade is set to A, and the noise contribution amplitude of the remaining positions is set to B, and A is greater than B. A gradual transition area is set with the phase angle position after returning to zero of each rear blade as the center to generate a rear blade noise basic phase waveform regarding the relationship between the noise and phase generated by all the rear blades.

[0142] Specifically, the noise contribution amplitude is set to 1 at the phase where the blade is located, and the noise contribution amplitude is set to 0.1 at the phase where the blade is not located. To ensure continuity, a sinusoidal gradient transition area with a range of 360° / N*0.25 is set with the phase where the blade is located as the center to simulate the low-speed area formed by the blade wake, such as Figure 7 The figure shows a one-dimensional waveform generated by a fan with nine unequally spaced blades, that is, a basic phase waveform of the front blade noise generated by a fan with nine unequally spaced blades.

[0143] Then, at multiple sampling moments, the front blade rotation angle of the front blade is determined according to the front fan blade speed, and the rear blade rotation angle of the rear blade is determined according to the rear fan blade speed. The waveform after the front blade noise basic phase waveform is moved in the rotation direction by the front blade rotation angle is used as the phase waveform at the front blade noise sampling moment, and the waveform after the rear blade noise basic phase waveform is moved in the rotation direction by the rear blade rotation angle is used as the phase waveform at the rear blade noise sampling moment.

[0144] Specifically, the generated front blade noise basic phase waveform and rear blade noise basic phase waveform are superimposed on the front and rear fan blade rotation speeds respectively to produce waveform changes over time, simulating the process of sound waves acting on a single point.

[0145] Among them, the front fan blade speed and the rear fan blade speed can be the same or different, which is determined according to the design needs. Since all the front blades in the front fan blades rotate at the same time, and all the rear blades in the rear fan blades rotate at the same time, the front fan blade speed and the rear fan blade speed represent the rotation angle of the blades per unit time. Therefore, at each sampling moment, the front blade rotation angle of the front blade from the starting moment can be converted according to the front fan blade speed, and the front blade noise basic phase waveform is moved in the rotation direction by the front blade rotation angle, so as to obtain the waveform at the sampling moment as the phase waveform of the front blade noise sampling moment. Figure 9 The figure shows the phase waveform of the front blade noise at a specific sampling moment. Similarly, at each sampling moment, the rear blade rotation angle from the starting moment can be calculated based on the rear blade speed. The rear blade noise base phase waveform is then shifted in the direction of rotation by the rear blade rotation angle to obtain the waveform at that sampling moment, which serves as the rear blade noise phase waveform at the sampling moment.

[0146] Then, the phase waveform of the front blade noise at the sampling moment is discretized to obtain the front blade noise column vector, and the phase waveform of the rear blade noise at the sampling moment is discretized to obtain the rear blade noise column vector. The dot product of the front blade noise column vector and the rear blade noise column vector is calculated as the superimposed noise at the sampling moment.

[0147] Specifically, the phase waveform at the front blade noise sampling time is a continuous value. A certain discrete number is selected to discretize 360° into a discrete number of discrete phase angles. The noise contribution amplitudes of all discrete phase angles at the front blade noise sampling time are combined to form the front blade noise column vector. Similarly, the phase waveform at the rear blade noise sampling time is a continuous value. The same discrete number is selected as the phase waveform at the front blade noise sampling time, and 360° is discretized into a discrete number of discrete phase angles. The noise contribution amplitudes of all discrete phase angles at the rear blade noise sampling time are combined to form the rear blade noise column vector.

[0148] Then, the dot product of the front blade noise column vector and the rear blade noise column vector is calculated as the superimposed noise at the sampling moment. Specifically, the front blade noise column vector is transposed and then dot-multiplied by the rear blade noise column vector, and the resulting scalar is used as the superimposed noise at the sampling moment.

[0149] By combining the superimposed noises at multiple sampling moments, we can obtain a time domain superimposed waveform showing the relationship between the superimposed noise and time.

[0150] This embodiment implements interference simulation of front and rear blades and optimizes the unequal spacing distribution strategy of the counter-rotating fan through a simplified one-dimensional order noise prediction model.

[0151] like Figure 10The flowchart of the noise simulation process for unequally spaced blades of an axial-flow counter-rotating fan according to the preferred embodiment of the present invention is shown, including:

[0152] Step S301, using a front blade noise one-dimensional waveform generator module, based on the modulation angle, adopting a blade unequal spacing distribution modulation strategy to generate a front blade noise basic phase waveform;

[0153] Step S1002, using a rear blade noise one-dimensional waveform generator module, based on the modulation angle, and using a blade unequal spacing distribution modulation strategy to generate a rear blade noise basic phase waveform;

[0154] Step S1003, obtaining the front fan blade rotation speed;

[0155] Step S1004, obtaining the rear fan blade rotation speed;

[0156] Step S1005, statistically superimposing the interference order noise of the front blade, the rear blade, and the front and rear blades;

[0157] Step S1006: If the order noise is Pareto optimal, execute step S1007; otherwise, execute steps S301 and S1002 again;

[0158] Step S1007: outputting the modulation strategies of the front and rear blades.

[0159] Specifically, according to the blade unequal spacing distribution modulation strategy, the distribution phase of each blade of the front and rear fan blades is obtained, and the Figure 10 In the process, Python code is compiled to simulate the front and rear fan blades and their mutual interference and the simulated noise energy generated. After performing FFT transformation on it, the contribution of each order of noise energy to the sound pressure level is obtained. Taking the highest order contribution to the sound pressure level as the target and the modulation angles of the front and rear fan blades as variables, the optimization is performed based on the Pareto optimal algorithm to obtain the optimal modulation strategy for the front and rear fan blades.

[0160] The Pareto optimality of order noise is evaluated through self-programming code. The basic judgment process of the code is as follows:

[0161] 1. Generate the noise waveforms produced by the front and rear fan blades:

[0162] The phase of each blade on the circumference of the fan blade is generated according to the modulation strategy of unequal blade spacing. The noise contribution amplitude is set to 1 for the phase where the blade is located, and the noise contribution amplitude is set to 0.1 for the phase where the non-blade is located. To ensure continuity, a sinusoidal gradient transition area with a range of 360° / N*0.25 is set with the phase where the blade is located as the center to simulate the low-speed area formed by the blade wake, such as Figure 7 The figure shows a one-dimensional waveform generated by a fan with nine unequally spaced blades;

[0163] 2. Superimpose the two generated waveforms with the front and rear blade speeds, respectively, to produce waveform changes over time, simulating the effect of sound waves on a single point;

[0164] 3. Superimpose the two waveforms, convert the time domain signal into a frequency domain signal through Fast Fourier Transform (FFT), and extract the order of focus. For example, for a seven-blade fan, the seventh-order noise is the largest, and for a nine-blade fan, the ninth-order noise is the largest. Record the order noise results, such as Figure 8 The figure is a schematic diagram of the FFT results of the front and rear blade interference, where the corresponding peak frequencies are the frequencies of each order, and the amplitude corresponding to the peak is the simulated energy value of the order noise;

[0165] 4. When there is less data, the DOE strategy is adopted to select the result with the smallest order noise to output the modulation angles of the front and rear blades; when there is more data, the Pareto optimal strategy is adopted to extract the result with the smallest order noise to output the modulation angles of the front and rear blades.

[0166] This embodiment optimizes the unequal spacing distribution strategy of counter-rotating fans through a simplified one-dimensional order noise prediction model.

[0167] Based on the same inventive concept, Figure 11 FIG2 is a schematic diagram of a counter-rotating fan blade modulation device according to an embodiment of the present invention, comprising:

[0168] A phase angle modulation module 1101 is configured to modulate the phases of multiple blades of a counter-rotating fan until the phase angle differences of the multiple blades are unequal, thereby obtaining a modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles;

[0169] The zeroing module 1102 is used to symmetrically adjust the modulated phase angles of the plurality of blades until the center of mass of the blade coincides with the axis position of the blade.

[0170] The present invention modulates the circumferential phase angles of multiple blades in a counter-rotating fan to reduce the order noise and overall noise generated during blade rotation. Symmetrical adjustment of the modulated phase angles of the blades returns the blade's center of mass to zero. While improving order noise in axial-flow counter-rotating fans, the present invention maintains the blade's center of mass on the axis of rotation, eliminating the need for counterweights or other methods to adjust the blade's center of mass, reducing costs and simplifying the fan's overall structure.

[0171] In one embodiment, symmetrically adjusting the modulated phase angles of the plurality of blades until the center of mass of the blade coincides with the axis of the blade includes:

[0172] Selecting one or more blade groups from all the blades as blade groups to be adjusted, each blade group to be adjusted includes two axially symmetrical blades;

[0173] Determine the zeroing angle. In the same group of blades to be adjusted, increase the modulated phase angle of one blade by the zeroing angle to obtain the corresponding zeroing phase angle, reduce the modulated phase angle of another blade by the zeroing angle to obtain the corresponding zeroing phase angle, and the zeroing phase angles corresponding to the modulated phase angles of the remaining blades outside the blade group to be adjusted are the same as the modulated phase angle.

[0174] In one embodiment:

[0175] The modulation includes: calculating the equidistant phase angles of each blade in the circumferential direction of the counter-rotating fan under uniform distribution conditions, and calculating the modulated phase angle of the i-th blade based on the modulation angle as follows: α A ′=α A +θsinα A ; or α A ′=α A +θcosα A , where α i is the equidistant phase angle of the i-th blade, α i ′ is the modulated phase angle of the i-th blade after modulation, and θ is the modulation angle;

[0176] The determination of the zeroing angle includes: finding a zeroing angle that satisfies the optimization formula by the least square method, and calculating the phase angle of the modulated blade α i ′=α i +θsinα i In the case of , the optimization formula is: After calculating the modulation phase angle of the i-th blade, it is α i ′=α i +θcosα i In the case of , the optimization formula is: Wherein, N is the number of blades, α i " is the phase angle of the i-th blade after returning to zero.

[0177] In one embodiment, the blades of the front blades of the counter-rotating fan are front blades, and the blades of the rear blades of the counter-rotating fan are rear blades. The device further includes an order noise optimization module for:

[0178] The front blades and the rear blades are modulated respectively based on different modulation angles, and after the centers of mass of the front blades and the rear blades are returned to the axis position, for each modulation angle, the order noise of the superimposed noise of all the front blades and all the rear blades is calculated, wherein the modulation angles include a front blade modulation angle for modulating the front blades and a rear blade modulation angle for modulating the rear blades;

[0179] The front blade modulation angle when the order noise is optimal is selected as the front blade optimal modulation angle, and the rear blade modulation angle is selected as the rear blade optimal modulation angle and outputted.

[0180] In one embodiment, the calculating the order noise of the superimposed noise of all the front blades and all the rear blades includes:

[0181] Calculating a time domain superposition waveform of the relationship between the superposition noise and time;

[0182] transforming the time domain superposition waveform into a frequency domain waveform;

[0183] Order noise is extracted from the frequency domain waveform.

[0184] In one embodiment, the calculating of the time domain superposition waveform of the relationship between the superposition noise of the noise generated by all the front blades and the noise generated by all the rear blades and time includes:

[0185] generating a front blade noise basic phase waveform related to the phase relationship of the noise generated by all the front blades and a rear blade noise basic phase waveform related to the phase relationship of the noise generated by all the rear blades;

[0186] At multiple sampling moments, the front blade rotation angle of the front blade rotated is determined according to the front blade speed, the rear blade rotation angle of the rear blade rotated is determined according to the rear blade speed, the waveform of the front blade noise basic phase waveform after being shifted in the rotation direction by the front blade rotation angle is used as the phase waveform of the front blade noise sampling moment, and the waveform of the rear blade noise basic phase waveform after being shifted in the rotation direction by the rear blade rotation angle is used as the phase waveform of the rear blade noise sampling moment;

[0187] Discretizing the phase waveform of the front blade noise at the sampling moment to obtain a front blade noise column vector, discretizing the phase waveform of the rear blade noise at the sampling moment to obtain a rear blade noise column vector, and taking the dot product of the front blade noise column vector and the rear blade noise column vector as the superimposed noise at the sampling moment;

[0188] A time domain superposition waveform regarding the relationship between the superposition noise and time is generated according to the superposition noise corresponding to all sampling moments.

[0189] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0190] like Figure 12 FIG. 1 is a schematic diagram of the hardware structure of an electronic device of the present invention, comprising:

[0191] at least one processor 1201; and,

[0192] A memory 1202 in communication with at least one of the processors 1201; wherein,

[0193] The memory 1202 stores instructions that can be executed by at least one of the processors. The instructions are executed by at least one of the processors to enable the at least one of the processors to perform the counter-rotating fan blade modulation method as described above.

[0194] Figure 12 A processor 1201 is taken as an example.

[0195] The electronic device may further include an input device 1203 and a display device 1204 .

[0196] The processor 1201, the memory 1202, the input device 1203 and the display device 1204 may be connected via a bus or other means, with the figure taking the bus connection as an example.

[0197] The memory 1202 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs, and modules, such as the program instructions / modules corresponding to the counter-rotating fan blade modulation method in the embodiment of the present application, for example, Figure 1 、 Figure 2 The processor 1201 executes the non-volatile software programs, instructions and modules stored in the memory 1202 to perform various functional applications and data processing, that is, to implement the counter-rotating fan blade modulation method in the above embodiment.

[0198] The memory 1202 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created according to the use of the counter-rotating fan blade modulation method, etc. In addition, the memory 1202 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 1202 may optionally include a memory remotely located relative to the processor 1201, and these remote memories may be connected to a device that executes the counter-rotating fan blade modulation method via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0199] The input device 1203 can receive user clicks and generate signal inputs related to user settings and function control of the counter-rotating fan blade modulation method. The display device 1204 can include a display device such as a display screen.

[0200] The one or more modules are stored in the memory 1202 and, when executed by the one or more processors 1201 , perform the counter-rotating fan blade modulation method in any of the above method embodiments.

[0201] The present invention modulates the circumferential phase angles of multiple blades in a counter-rotating fan to reduce the order noise and overall noise generated during blade rotation. Symmetrical adjustment of the modulated phase angles of the blades returns the blade's center of mass to zero. While improving order noise in axial-flow counter-rotating fans, the present invention maintains the blade's center of mass on the axis of rotation, eliminating the need for counterweights or other methods to adjust the blade's center of mass, reducing costs and simplifying the fan's overall structure.

[0202] An embodiment of the present invention provides a storage medium storing computer instructions. When a computer executes the computer instructions, the storage medium is used to execute all steps of the counter-rotating fan blade modulation method as described above.

[0203] In the context of the present disclosure, a storage medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or apparatus. The storage medium may be a machine-readable signal medium or a machine-readable storage medium. Alternatively, the storage medium may be a non-transitory computer-readable storage medium, for example, a non-transitory computer-readable storage medium may be a ROM, a random access memory (RAM), a compact disc read-only memory (CD-ROM), a magnetic tape, a floppy disk, and an optical data storage device.

[0204] An embodiment of the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the above-mentioned counter-rotating fan blade bending method.

[0205] An embodiment of the present invention provides a counter-rotating fan, comprising a fan and blades arranged along the circumference of the counter-rotating fan, wherein the blades are modulated using the counter-rotating fan blade modulation method as described above.

[0206] An embodiment of the present invention provides a vehicle, comprising the counter-rotating fan as described above.

[0207] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for modulating counter-rotating fan blades, characterized in that: include: Modulating the phases of multiple blades of a counter-rotating fan until the multiple phase angle differences of each blade are unequal, thereby obtaining a modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles; The modulated phase angles of the plurality of blades are symmetrically adjusted until the center of mass of the fan blade coincides with the axis position of the fan blade.

2. The counter-rotating fan blade modulation method according to claim 1, characterized in that: The symmetrically adjusting the modulated phase angles of the plurality of blades until the center of mass of the fan blade coincides with the axis position of the fan blade includes: Selecting one or more blade groups from all the blades as blade groups to be adjusted, each blade group to be adjusted includes two axially symmetrical blades; Determine the zeroing angle. In the same group of blades to be adjusted, increase the modulated phase angle of one blade by the zeroing angle to obtain the corresponding zeroing phase angle, reduce the modulated phase angle of another blade by the zeroing angle to obtain the corresponding zeroing phase angle, and the zeroing phase angles corresponding to the modulated phase angles of the remaining blades outside the blade group to be adjusted are the same as the modulated phase angle.

3. The counter-rotating fan blade modulation method according to claim 2, characterized in that: The modulation includes: calculating the equidistant phase angles of each blade in the circumferential direction of the counter-rotating fan under uniform distribution conditions, and calculating the modulated phase angle of the i-th blade based on the modulation angle as follows: α i ′=α i +θsinα i ; or α i ′=α i +θcosα i , where α i is the equidistant phase angle of the i-th blade, α i ′ is the modulated phase angle of the i-th blade after modulation, and θ is the modulation angle; The determination of the zeroing angle includes: finding a zeroing angle that satisfies the optimization formula by the least square method, and calculating the phase angle of the modulated blade α i ′=α i +θsinα i In the case of , the optimization formula is: After calculating the modulation phase angle of the i-th blade, it is α i ′=α i +θcosα i In the case of , the optimization formula is: Wherein, N is the number of blades, α i " is the phase angle of the i-th blade after returning to zero.

4. The counter-rotating fan blade modulation method according to claim 1, characterized in that: The blades of the front blades of the counter-rotating fan are front blades, and the blades of the rear blades of the counter-rotating fan are rear blades, and the method further includes: The front blades and the rear blades are modulated respectively based on different modulation angles, and after the centers of mass of the front blades and the rear blades are returned to the axis position, for each modulation angle, the order noise of the superimposed noise of all the front blades and all the rear blades is calculated, wherein the modulation angles include a front blade modulation angle for modulating the front blades and a rear blade modulation angle for modulating the rear blades; The front blade modulation angle when the order noise is optimal is selected as the front blade optimal modulation angle, and the rear blade modulation angle is selected as the rear blade optimal modulation angle and outputted.

5. The method for modulating counter-rotating fan blades according to claim 4, characterized in that: The calculating the order noise of the superimposed noise of all the front blades and all the rear blades includes: Calculating a time domain superposition waveform of the relationship between the superposition noise and time; transforming the time domain superposition waveform into a frequency domain waveform; Order noise is extracted from the frequency domain waveform.

6. The counter-rotating fan blade modulation method according to claim 5, characterized in that: The calculating of the time domain superposition waveform of the relationship between the superposition noise of the noise generated by all the front blades and the noise generated by all the rear blades and time includes: generating a front blade noise basic phase waveform related to the phase relationship of the noise generated by all the front blades and a rear blade noise basic phase waveform related to the phase relationship of the noise generated by all the rear blades; At multiple sampling moments, the front blade rotation angle of the front blade rotated is determined according to the front blade speed, the rear blade rotation angle of the rear blade rotated is determined according to the rear blade speed, the waveform of the front blade noise basic phase waveform after being shifted in the rotation direction by the front blade rotation angle is used as the phase waveform of the front blade noise sampling moment, and the waveform of the rear blade noise basic phase waveform after being shifted in the rotation direction by the rear blade rotation angle is used as the phase waveform of the rear blade noise sampling moment; Discretizing the phase waveform of the front blade noise at the sampling moment to obtain a front blade noise column vector, discretizing the phase waveform of the rear blade noise at the sampling moment to obtain a rear blade noise column vector, and taking the dot product of the front blade noise column vector and the rear blade noise column vector as the superimposed noise at the sampling moment; A time domain superposition waveform regarding the relationship between the superposition noise and time is generated according to the superposition noise corresponding to all sampling moments.

7. A counter-rotating fan blade modulation device, characterized in that: include: A phase angle modulation module is used to modulate the phases of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are unequal, thereby obtaining a modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles; The zeroing module is used to symmetrically adjust the modulated phase angles of the plurality of blades until the center of mass of the fan blade coincides with the axis position of the fan blade.

8. An electronic device, characterized in that: include: at least one processor; as well as, a memory communicatively connected to at least one of the processors; wherein, The memory stores instructions that can be executed by at least one processor, and the instructions are executed by at least one processor to enable at least one processor to perform the counter-rotating fan blade modulation method according to any one of claims 1 to 6.

9. A storage medium, characterized in that: The storage medium stores computer instructions, and when a computer executes the computer instructions, it is used to execute all steps of the counter-rotating fan blade modulation method according to any one of claims 1 to 6.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the counter-rotating fan blade bending method according to any one of claims 1 to 6 is implemented.

11. A counter-rotating fan, characterized in that: The invention comprises a fan and blades arranged along the circumferential direction of the counter-rotating fan, wherein the blades are modulated by the counter-rotating fan blade modulation method according to any one of claims 1 to 6.

12. A vehicle, characterized in that: The device comprises the counter-rotating fan according to claim 11.

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