Modulation method and device for contra-rotating fan blades, contra-rotating fan and vehicle

Abstract

The application discloses a method and device for modulating blades of a counter-rotating fan, a counter-rotating fan and a vehicle. The method comprises: modulating phases of a plurality of blades of a fan blade of the counter-rotating fan to obtain modulated phase angles of each blade; and symmetrically adjusting the modulated phase angles of the plurality of blades to make a centroid of the fan blade coincide with an axial position of the fan blade. After the phases of the plurality of blades in the circumferential direction of the fan blade of the counter-rotating fan are modulated, the application reduces order noise and overall noise generated in the rotating process of the blades. The modulated phase angles of the plurality of blades are symmetrically adjusted, so that the centroid of the fan blade is zeroed. While the application improves order noise in the axial counter-rotating fan, the centroid of the fan blade is kept on the rotating shaft, and the centroid of the fan blade does not need to be adjusted by a counterweight or the like, so that the cost is reduced and the overall structure of the fan is simplified.

Description

Technical Field

[0001] This invention relates to the field of fan-related technology, and in particular to a method, apparatus, electronic device, storage medium, computer program product, counter-rotating fan, and vehicle for modulating counter-rotating fan blades. Background Technology

[0002] Existing counter-rotating fans use blades with evenly spaced distribution. However, typical applications require high rotational speeds to achieve large airflow and high air pressure. Under high speed and high airflow conditions, a particularly noticeable, piercing "buzzing" noise is easily produced. This noise frequency is usually related to the fan blade rotation speed and is referred to as the fan's order noise. This phenomenon is typically caused by one or more frequencies having noise levels far exceeding the average noise level of other frequencies, thus creating a noticeable and uncomfortable sensation and affecting a person's psychological comfort after hearing the noise.

[0003] To address this, existing technologies employ an unequally spaced blade design for counter-rotating fans to reduce noise.

[0004] However, the uneven distribution of blades changes the center of mass of the blades, causing them to be off the axis of rotation. Existing technologies require adjusting the center of mass of the blades by adding counterweights, which increases costs and complicates the structure. Summary of the Invention

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

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

[0007] The phase of multiple blades of a counter-rotating fan is modulated until the multiple phase angle differences of each blade are not equal, thereby obtaining the 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 multiple blades are symmetrically adjusted until the centroid of the blade coincides with the axis of the blade.

[0009] Further, the symmetrical adjustment of the modulated phase angle of the plurality of blades until the centroid of the fan blade coincides with the axial center of the fan blade includes:

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

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

[0012] Furthermore:

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

[0014] The determination of the zeroing angle includes: finding the zeroing angle that satisfies the optimization formula using the least squares method, and calculating the phase angle α after modulation of the i-th blade. i ′=α i +θsinα i In this case, the optimization formula is: The phase angle after modulation of the i-th blade is calculated to be α. i ′=α i +θcosα i In this case, the optimization formula is: Where N is the number of leaves, α i " is the phase angle after the i-th blade is zeroed out.

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

[0016] Based on different modulation angles, the front blade and the rear blade are modulated respectively. After the centroids of the front blade and the rear blade return 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. The modulation angle includes the front blade modulation angle for modulating the front blade and the rear blade modulation angle for modulating the rear blade.

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

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

[0019] Calculate the time-domain superimposed waveform of the superimposed noise versus time;

[0020] Transform the time-domain superimposed waveform into a frequency-domain waveform;

[0021] Extract order noise from the frequency domain waveform.

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

[0023] Generate the basic phase waveforms of the front blade noise and the rear blade noise with respect to the noise and phase relationship generated by all the front blades, respectively;

[0024] At multiple sampling times, the rotation angle of the front blade is determined based on the rotation speed of the front blade, and the rotation angle of the rear blade is determined based on the rotation speed of the rear blade. The waveform of the front blade noise basis phase waveform after shifting the front blade rotation angle in the rotation direction is taken as the front blade noise sampling time phase waveform, and the waveform of the rear blade noise basis phase waveform after shifting the rear blade rotation angle in the rotation direction is taken as the rear blade noise sampling time phase waveform.

[0025] The phase waveform of the noise sampling moment of the front blade is discretized to obtain the front blade noise column vector, and the phase waveform of the noise sampling moment of the rear blade is discretized to obtain the rear blade noise column vector. The dot product of the noise column vector of the front blade and the noise column vector of the rear blade is used as the superimposed noise at the sampling moment.

[0026] Generate a time-domain superimposed waveform relating superimposed noise to time based on the superimposed noise corresponding to all sampling times.

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

[0028] A phase angle modulation module is used to modulate the phase of multiple blades of a counter-rotating fan until the phase angle differences of multiple blades are not equal, thereby obtaining the 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 angle of multiple blades until the centroid of the fan blade coincides with the axis of the fan blade.

[0030] This 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 to enable 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 that stores computer instructions, which, when executed by a computer, are used to perform all the steps of the aforementioned counter-rotating fan blade modulation method.

[0035] The present invention provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the aforementioned method for bending counter-rotating fan blades.

[0036] The present invention provides a counter-rotating fan, including 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 described above.

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

[0038] This invention modulates the phase angles of multiple blades along the circumferential direction of the fan blades in a counter-rotating fan, thereby reducing the order noise and overall noise generated during blade rotation. By symmetrically adjusting the modulated phase angles of multiple blades, the center of mass of the fan blades is brought to zero. This invention improves the order noise in an axial counter-rotating fan while keeping the center of mass of the fan blades on the axis of rotation, eliminating the need for adjusting the center of mass through counterweights or other means, thus reducing costs and simplifying the overall fan structure. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating a method for modulating the blades of a counter-rotating fan according to an embodiment of the present invention.

[0040] Figure 2 This is a flowchart illustrating a method for modulating the blades of a counter-rotating fan, according to another embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram of the front blade of an example of the present invention;

[0042] Figure 4 This is a schematic diagram of the rear blade of an example of the present invention;

[0043] Figure 5 for Figure 3 A schematic diagram of the modulation of the front blade is shown;

[0044] Figure 6 A flowchart illustrating the preferred embodiment of a method for modulating the blades of a counter-rotating fan according to the present invention;

[0045] Figure 7 A schematic diagram of a one-dimensional waveform generated for a nine-bladed fan with unequal spacing.

[0046] Figure 8 A schematic diagram of the FFT results of the interference between the front and rear fan blades;

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

[0048] Figure 10 A flowchart illustrating the noise simulation of an axial-flow counter-rotating fan with unequally spaced blades, representing the preferred embodiment of the present invention.

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

[0050] Figure 12 This is a schematic diagram of the hardware structure of an electronic device according to the present invention. Detailed Implementation

[0051] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same 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, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0052] like Figure 1 The diagram shown is a flowchart of a method for modulating the blades of a counter-rotating fan according to an embodiment of the present invention, comprising:

[0053] Step S101: Modulate the phase of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are not equal, to obtain the 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 angle of the plurality of blades until the centroid of the fan blade coincides with the axis 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 phase of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are not equal, to obtain the modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles.

[0057] Specifically, modulation refers to the non-uniform modulation of the phase of multiple blades, which means modulating the phase angle of each blade to distribute it non-uniformly. By modulating the equidistant phase angle of each blade, the modulated phase angle of each blade is obtained, thereby reducing order noise.

[0058] Modulation can be obtained by designers based on experience or experimental methods.

[0059] In some embodiments, modulating the phase of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are not equal, to obtain the modulated phase angle of each blade, includes:

[0060] Calculate the equidistant phase angles of each blade in the circumferential direction of the fan blade under uniform distribution conditions, and modulate the equidistant phase angles of multiple blades based on the modulation angle to obtain the modulated phase angle of each blade.

[0061] Specifically, to solve for the equidistant phase angles 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 multiple blades are modulated based on the modulation angle to obtain the 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, symmetrically adjusting the modulated phase angle of the plurality of blades until the centroid of the fan blade coincides with the axis of the fan blade.

[0065] After executing step S101, since the differences between the modulated phase angles are not completely equal, the centroid of the modulated fan blade will not be at the axis center position; it may be offset in the x-direction or the y-direction. Therefore, step S102 is executed to readjust the phase angles of some blades so that the centroid of the blade returns to zero. Here, returning the centroid to zero means that the centroid 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, the counter-rotating fan includes a front blade 300 and a rear blade 400. The front blade 300 includes a plurality of front blades 301, and the rear blade 400 includes a plurality of rear blades 401. The phase angle of the blade is the angle between a selected reference point on the blade and the center line. The reference points of all blades are consistent.

[0068] This invention modulates the phase angles of multiple blades along the circumferential direction of the fan blades in a counter-rotating fan, thereby reducing the order noise and overall noise generated during blade rotation. By symmetrically adjusting the modulated phase angles of multiple blades, the center of mass of the fan blades is brought to zero. This invention improves the order noise in an axial counter-rotating fan while keeping the center of mass of the fan blades on the axis of rotation, eliminating the need for adjusting the center of mass through counterweights or other means, thus reducing costs and simplifying the overall fan structure.

[0069] like Figure 2 The diagram shown is a flowchart of a method for modulating the blades of a counter-rotating fan according to another embodiment of the present invention, comprising:

[0070] Step S201: Modulate the phase of multiple blades of the counter-rotating fan until the phase angle differences of multiple blades are not equal, to obtain 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 fan blades 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: α i ′=α i +θsinα i ; or α i ′=α A +θcosα A , where α A Let α be the equidistant phase angle of the i-th blade. i ′ is the modulated phase angle of the i-th blade after modulation, and θ is the modulation angle.

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

[0073] Step S203: Determine the zeroing angle. In the same group of blades to be adjusted, increase the zeroing angle of the modulated phase angle of one blade to obtain the corresponding zeroing phase angle, and decrease the zeroing angle of the modulated phase angle of another blade to obtain the corresponding zeroing phase angle. The zeroing phase angles corresponding to the modulated phase angles of the remaining blades outside the group of blades to be adjusted are the same as the modulated phase angles.

[0074] In one embodiment, determining the zero-return angle includes: finding the zero-return angle that satisfies the optimization formula using the least squares method, and calculating the modulation phase angle of the i-th blade as α. i ′=α i +θsinα i In this case, the optimization formula is: The phase angle after modulation of the i-th blade is calculated to be α. i ′=α i +θcosα i In this case, the optimization formula is: Where N is the number of leaves, α i " is the phase angle after the i-th blade is zeroed out.

[0075] Specifically, step S201 is first executed to modulate the phase of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are not equal, thereby obtaining the modulated phase angle of each blade, wherein the phase angle difference is the difference between two adjacent modulated phase angles.

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

[0077] Specifically, if the number of blades is odd, one blade is selected as the reference blade. 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 blades is even, all blades are modulated.

[0079] In one embodiment, the modulation includes: calculating the equidistant phase angles of each blade in the circumferential direction of the fan blades 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: α i ′=α i +θsinα i ; or α i ′=α i +θcosα i , where α i Let α be the equidistant phase angle of the i-th blade. i ′ is the modulated phase angle of the i-th blade after modulation, and θ is the modulation angle.

[0080] Specifically, the equidistant phase angles of each blade under uniform distribution conditions are calculated, with a total number of blades of... Then the phase of the i-th blade, that is, the equidistant phase angle of the i-th blade, is: Where, α i Let be the equidistant phase angle of the i-th blade.

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

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

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

[0084] a i ′=a i +θsina i

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

[0086] α i ′=α i +θcosα i .

[0087] This embodiment significantly improves the order noise phenomenon in axial counter-rotating fans by modulating the blade distribution, reducing discomfort caused by prominent single noise decibel values, and maximizing the reduction of blade order noise levels. Simultaneously, this embodiment modulates the blades using specific trigonometric functions. Since 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 performed to select one or more groups of blades from all the blades as the blade groups to be adjusted, each group of blades to be adjusted including two axially symmetrical blades.

[0089] Specifically, two sets of blades are typically selected as the blade sets to be adjusted. If only two blades are adjusted, the angle required for center of gravity reset is relatively large, which generally results in blade overlap (i.e., the projections of the blades coincide when viewed from the axial direction). This design is either not precise enough or very costly for mass production. If six blades are adjusted, for a fan blade with only seven blades, the center of gravity reset will essentially result in a similar effect to the original, undistributed blade configuration, with little change. Therefore, the purpose of the uneven distribution for noise reduction becomes meaningless. Therefore, it is preferable to symmetrically adjust four blades, i.e., two sets of blades to be adjusted.

[0090] Then, step S203 is executed 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 decreased by the zeroing angle to obtain the corresponding zeroing phase angle. The zeroing phase angle corresponding to the modulated phase angle of the remaining blades outside the group of blades to be adjusted is the same as the modulated phase angle.

[0091] Each set of blades to be adjusted comprises two blades whose modulated phase angles are symmetrical about the x-axis or y-axis. Within the same set of blades, the modulated phase angle of one blade is increased by a zero-point angle to obtain a zero-point phase angle, while the modulated phase angle of the other blade is decreased by a zero-point angle to obtain a zero-point phase angle. This simultaneously moves the modulated phase angles of the two blades in the same set closer to or further away from the axis of symmetry, thereby adjusting the blade's center of mass (i.e., the blade's center of gravity) until it 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-2nd)th blades are selected as a blade group, and the 3rd and (N-3rd)th blades are selected as a blade group. The modulated phase angle of the 2nd and 3rd blades is reduced by the zero-return angle to obtain the zero-return phase angle, and the modulated phase angle of the (N-2nd)th and (N-3rd)th blades is increased by the zero-return angle to obtain the zero-return phase angle.

[0093] In some embodiments, when N is even, the 2nd and (N-1)th blades are selected as one blade group, and the 3rd and (N-2)th blades are selected as another blade group. The modulated phase angle of the 2nd and 3rd blades is reduced by the zero-return angle to obtain the zero-return phase angle, and the modulated phase angle of the (N-1)th and (N-2)th blades is increased by the zero-return angle to obtain the zero-return phase angle.

[0094] Specifically, the least squares method is used to find the zeroing angle that makes the centroid of the fan blade zero, and the modulated phase angle of the blades included in the blade group to be adjusted based on the zeroing angle.

[0095] The least squares method is an optimization algorithm that can be used to find the zeroing angle that makes the centroid of the fan blade zero.

[0096] In one embodiment, determining the zero-return angle includes: finding the zero-return angle that satisfies the optimization formula using the least squares method, and calculating the modulation phase angle of the i-th blade as α. i ′=α i +θsinα i In this case, the optimization formula is: The phase angle after modulation of the i-th blade is calculated to be α. A ′=α A +θcosα A In this case, the optimization formula is: Where N is the number of leaves, α A " is the phase angle after the i-th blade is zeroed out.

[0097] Specifically, for the modulated phase angle using sine function modulation, the centroid will change in the x-direction. Therefore, selecting... Optimization is needed. However, for the phase angle after modulation using cosine function modulation, the centroid will change in the y-direction; therefore, the optimal choice is... Seeking excellence.

[0098] The least squares method is used to find the zeroing angle β that satisfies the optimization condition. That is, based on the zeroing angle β, the modulated phase angle of the blades of the blade group to be adjusted is adjusted to obtain the zeroing phase angle, while the zeroing phase angle of the other blades is kept as the modulated phase angle. The zeroing angle is found to minimize the sum of the sin values ​​or the sum of the cos values ​​of the zeroing phase angles of all blades.

[0099] The zero-reset angle β, which satisfies the optimization condition, is used to adjust the modulated phase angle of the blades in the blade group to be adjusted, so as to obtain the zero-reset phase angle. The zero-reset phase angle of the remaining blades is kept as the modulated phase angle, thereby making the centroid of the fan blades, including blades with unequal phase angles, return to the axis.

[0100] This embodiment uses an optimization algorithm to quickly determine the zeroing angle, thereby achieving an uneven distribution of blade spacing while keeping the blade centroid 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 zeroing phase angles of each front blade 301 are 43.86°, 78.59°, 117.88°, 162.05°, 197.95°, 242.12°, 281.41°, 316.14°, and 360°, respectively.

[0102] like Figure 5 As shown Figure 3 The diagram shows the modulation of the front blade. Figure 5 Point 1 represents the modulated phase angle of the first front blade, point 2 represents the modulated phase angle of the second front blade, point 3 represents the modulated phase angle of the third front blade, point 4 represents the modulated phase angle of the fourth front blade, point 5 represents the modulated phase angle of the fifth front blade, point 6 represents the modulated phase angle of the sixth front blade, point 7 represents the modulated phase angle of the seventh front blade, point 8 represents the modulated phase angle of the eighth front blade, and point 9 represents the modulated phase angle of the ninth front blade. The second and seventh front blades, which are symmetrical about the x-axis, are selected as one blade group, and the third and sixth front blades, which are symmetrical about the x-axis, are selected as another 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 zeroing phase angles of each rear blade 401 are 50.69°, 102.79°, 155.80°, 204.20°, 257.21°, 309.31°, and 360°, respectively.

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

[0105] This embodiment achieves a non-uniform blade distribution by multiplying the trigonometric function value of the equidistant phase angle of each blade by the modulation angle. Simultaneously, a suitable zero-point angle is effectively found using the least squares method, and based on the adjustment of the zero-point angle, the centroid of the fan blades is kept on the axis of rotation. Thus, while maintaining the centroid of the blades on the axis of rotation, the fan blades exhibit a non-uniform distribution, 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. The method further includes:

[0107] Based on different modulation angles, the front blade and the rear blade are modulated respectively. After the centroids of the front blade and the rear blade return 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. The modulation angle includes the front blade modulation angle for modulating the front blade and the rear blade modulation angle for modulating the rear blade.

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

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

[0110] The method in this embodiment also includes optimal modulation optimization of the front and rear blades and noise simulation for blades with unequal spacing.

[0111] Specifically, steps S101 to S102, or steps S201 to S203, are executed to modulate the front blade and the rear blade respectively based on different modulation angles. After the centroids of both the front and rear blades return to their axial center positions, for each modulation angle, the order noise of the superimposed noise of all the front blades and all the rear blades is calculated. 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 modulation angle of the front blade when the order noise is optimal is selected as the optimal modulation angle of the front blade, and the modulation angle of the rear blade is selected as the optimal modulation angle of the rear blade.

[0113] After obtaining the optimal modulation angle of the front blade and the optimal modulation angle of the rear blade, the zero-reset phase angle of each front blade under the optimal modulation angle of the front blade can be taken as the phase angle of the front blade, and the zero-reset phase angle of each rear blade under the optimal modulation angle of the rear blade can be taken as the phase angle of the rear blade.

[0114] Multiple different modulation angles can be set, and the order noise of each modulation angle can be calculated. Then, the modulation angle of the front blade when the order noise is optimal is selected as the optimal modulation angle of the front blade, and the modulation angle of the rear blade 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 blade and the rear blade are modulated based on different modulation angles. After the centroids of the front and rear blades return to their axial center positions, for each modulation angle, the order noise of the superposition of the noise generated by all the front blades and the noise generated by all the rear blades is calculated. The modulation angles include the front blade modulation angle used to modulate the front blades and the rear blade modulation angle used to modulate the rear blades. If the order noise is minimized, the front blade modulation angle of this order noise optimization step is taken as the optimal modulation angle of the front blades and the rear blade modulation angle is taken as the optimal modulation angle of the rear blades. Otherwise, the modulation angles are modified and the order noise optimization step is performed again.

[0116] When there is little data, a Design of Experiments (DOE) strategy is adopted to select the result with the minimum order noise and output the optimal modulation angles of the front and rear blades. When there is a lot of data, a Pareto optimality strategy is adopted to extract the result with the minimum order noise and output the optimal modulation angles of the front and rear blades.

[0117] like Figure 6The flowchart shown is a working diagram of a method for modulating the blades of a counter-rotating fan, according to a preferred embodiment of the present invention, including:

[0118] Step S601: Determine the modulation angle of the front blade, calculate the equidistant phase angle of each front blade based on the modulation angle of the front blade, perform blade modulation on the blade level phase angle of the front blade, and then reset the centroid of the front blade to zero.

[0119] Step S602: Determine the modulation angle of the rear blades, calculate the equidistant phase angle of each rear blade based on the modulation angle of the rear blades, perform blade modulation on the blade level phase angle of the rear blades, and then reset the centroid of the rear blades to zero.

[0120] In step S603, if the order noise is Pareto optimal, then proceed to step S604; otherwise, proceed to steps S601 and S602 again.

[0121] Step S604: Output the modulation strategy for the front and rear blades.

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

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

[0124] Calculate the time-domain superimposed waveform of the superimposed noise versus time;

[0125] Transform the time-domain superimposed waveform into a frequency-domain waveform;

[0126] Extract order noise from the frequency domain waveform.

[0127] Specifically, the order noise of the superposition of the noise generated by all the front blades and the noise generated by all the rear blades is calculated, including:

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

[0129] Based on the phase of the front blade on the circumference and the phase of the rear blade on the circumference, calculate the time-domain superposition waveform of the superposition noise and time relationship between the noise generated by all the front blades and the noise generated by all the rear blades.

[0130] The time-domain superimposed waveform is converted into a frequency-domain waveform (frequency-domain signal) using a Fast Fourier Transform (FFT), and the order of interest is extracted. For example, for a seven-bladed fan, the seventh-order noise is the largest, so the order of interest is the seventh; for a nine-bladed fan, the ninth-order noise is the largest, so the order of interest is the ninth. The noise order results are recorded, such as... Figure 8 The results are FFT values ​​for the interference between the front and rear fan blades, where the corresponding peak frequencies are the frequencies of each order, and the amplitude of the peak is the simulated energy value of the order noise.

[0131] The order with the smallest noise is the one of priority, and the order with the smallest amplitude is the one of priority. The order with relatively small noise is the one with relatively small amplitude.

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

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

[0134] Generate the basic phase waveforms of the front blade noise and the rear blade noise with respect to the noise and phase relationship generated by all the front blades, respectively;

[0135] At multiple sampling times, the rotation angle of the front blade is determined based on the rotation speed of the front blade, and the rotation angle of the rear blade is determined based on the rotation speed of the rear blade. The waveform of the front blade noise basis phase waveform after shifting the front blade rotation angle in the rotation direction is taken as the front blade noise sampling time phase waveform, and the waveform of the rear blade noise basis phase waveform after shifting the rear blade rotation angle in the rotation direction is taken as the rear blade noise sampling time phase waveform.

[0136] The phase waveform of the noise sampling moment of the front blade is discretized to obtain the front blade noise column vector, and the phase waveform of the noise sampling moment of the rear blade is discretized to obtain the rear blade noise column vector. The dot product of the noise column vector of the front blade and the noise column vector of the rear blade is used as the superimposed noise at the sampling moment.

[0137] Generate a time-domain superimposed waveform relating superimposed noise to time based on the superimposed noise corresponding to all sampling times.

[0138] Specifically, the basic phase waveforms of the front blade noise and the phase relationship of the noise generated by all the front blades are first generated, and the basic phase waveforms of the rear blade noise and the phase relationship of the noise generated by all the rear blades are generated.

[0139] In some embodiments, generating the fundamental phase waveforms of the front blade noise with respect to the noise and phase relationship generated by all the front blades and the fundamental phase waveforms of the rear blade noise with respect to the noise and phase relationship generated by all the rear blades includes:

[0140] The noise contribution amplitude of each front blade at the zero-reset phase angle position is set to A, and the noise contribution amplitude of the other positions is set to B, where A is greater than B. A gradual transition region is set with the zero-reset phase angle position of each front blade as the center, and a front blade noise basic phase waveform with respect to the noise and phase relationship generated by all front blades is generated.

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

[0142] Specifically, the noise contribution amplitude is set to 1 for the phase where the blade is located, and 0.1 for the phases where the blade is not located. To ensure continuity, a sinusoidal gradual transition region of 360° / N*0.25 is set with the phase where the blade is located as the center to simulate the low-speed region of blade wake formation. Figure 7 The figure shows a one-dimensional waveform generated by a nine-bladed fan with unequal spacing, which is the front blade noise fundamental phase waveform generated by a nine-bladed fan with unequal spacing.

[0143] Then, at multiple sampling times, the rotation angle of the front blade is determined based on the front blade rotation speed, and the rotation angle of the rear blade is determined based on the rear blade rotation speed. The waveform of the front blade noise basis phase waveform after shifting the front blade rotation angle in the rotation direction is taken as the front blade noise sampling time phase waveform, and the waveform of the rear blade noise basis phase waveform after shifting the rear blade rotation angle in the rotation direction is taken as the rear blade noise sampling time phase waveform.

[0144] Specifically, the generated basic phase waveforms of the front blade noise and the rear blade noise are superimposed with the front and rear blade rotation speeds, respectively, to generate waveform changes over time and simulate the effect of sound waves on a single point.

[0145] The rotational speeds of the front and rear blades can be the same or different, depending on the design requirements. Since all the front blades in the front fan rotate simultaneously, and all the rear blades in the rear fan rotate simultaneously, the rotational speeds of the front and rear blades represent the rotation angle of the blades per unit time. Therefore, at each sampling moment, the rotational angle of the front blades since the initial moment can be calculated based on the front blade rotational speed. The fundamental phase waveform of the front blade noise is then shifted in the direction of rotation by this rotational angle to obtain the waveform at that sampling moment, which serves as the phase waveform of the front blade noise at the sampling moment. Figure 9 The figure shows the phase waveform of the front blade noise at a certain sampling moment. Similarly, at each sampling moment, the rotation angle of the rear blade since the initial moment can be calculated based on the rear blade rotation speed. The basic phase waveform of the rear blade noise is then shifted in the rotation direction by the rear blade rotation angle to obtain the waveform at that sampling moment, which is used as the phase waveform of the rear blade noise at the sampling moment.

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

[0147] Specifically, the phase waveform of the front blade noise sampling time is a continuous value. A certain number of discrete values ​​are selected, and 360° is discretized into a discrete number of discrete phase angles. The noise contribution amplitude of all discrete phase angles at the front blade noise sampling time is combined into a front blade noise column vector. Similarly, the phase waveform of the rear blade noise sampling time is a continuous value. The same number of discrete values ​​as the front blade noise sampling time phase waveform are selected, and 360° is discretized into a discrete number of discrete phase angles. The noise contribution amplitude of all discrete phase angles at the rear blade noise sampling time phase waveform is combined into a 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 time. Specifically, the front blade noise column vector is transposed and then multiplied by the rear blade noise column vector to obtain a scalar as the superimposed noise at the sampling time.

[0149] By combining the superimposed noise from multiple sampling times, we obtain the time-domain superimposed waveform of the superimposed noise versus time.

[0150] This embodiment simulates the interference between the front and rear blades and optimizes the unequal distribution strategy of the counter-rotating fan by using a simplified one-dimensional noise prediction model.

[0151] like Figure 10The diagram shown is a flowchart illustrating the noise simulation process of an axial-flow counter-rotating fan with unequal-pitch blades according to a preferred embodiment of the present invention, including:

[0152] Step S301: Using the front blade noise one-dimensional waveform generator module, based on the modulation angle, the blade non-uniform distribution modulation strategy is used to generate the front blade noise basic phase waveform.

[0153] Step S1002: Using the rear blade noise one-dimensional waveform generator module, based on the modulation angle, the blade non-uniform distribution modulation strategy is used to generate the rear blade noise basic phase waveform.

[0154] Step S1003: Obtain the front fan blade speed;

[0155] Step S1004: Obtain the rotational speed of the rear fan blade;

[0156] Step S1005: Statistically superimpose 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, then proceed to step S1007; otherwise, proceed to steps S301 and S1002 again.

[0158] Step S1007: Output the modulation strategy for the front and rear blades.

[0159] Specifically, based on the blade non-uniform distribution modulation strategy, the distribution phase of each blade in the front and rear fan blades is obtained, and then... Figure 10 The process involves using Python code to simulate the noise energy generated by the front and rear fan blades and their mutual interference. After performing an FFT transform, the contribution of each order of noise energy to the sound pressure level is obtained. Taking the contribution of the highest order to the sound pressure level as the target, and the modulation angles of the front and rear fan blades as variables, the Pareto optimal algorithm is used for optimization to obtain the optimal modulation strategy for the front and rear fan blades.

[0160] Pareto optimality for order noise is evaluated using self-programmed code. The basic decision-making process of the code is as follows:

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

[0162] Based on the unequal spacing modulation strategy of the blades, the phase of each blade on the circumference is generated. The noise contribution amplitude of the phase where the blade is located is set to 1, and the noise contribution amplitude of the phases where the blade is not located is set to 0.1. To ensure continuity, a sinusoidal gradual transition region 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 region of blade wake formation. Figure 7 The image shows a one-dimensional waveform generated by a nine-bladed fan with unequal spacing.

[0163] 2. The two generated waveforms are superimposed with the front and rear fan 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 to a frequency-domain signal using a Fast Fourier Transform (FFT), and extract the order of interest. For example, for a seven-bladed fan, the seventh-order noise is the largest, and for a nine-bladed fan, the ninth-order noise is the largest. Record the noise order results. Figure 8 This is a schematic diagram of the FFT results of the front and rear fan 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 little data, the DOE strategy is adopted to select the result with the smallest order noise and output the modulation angles of the front and rear fan blades; when there is a lot of data, the Pareto optimal strategy is adopted to extract the result with the smallest order noise and output the modulation angles of the front and rear fan blades.

[0166] This embodiment optimizes the unequal-distance distribution strategy of the counter-rotating fan by using a simplified one-dimensional noise prediction model.

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

[0168] The modulation phase angle module 1101 is used to modulate the phase of multiple blades of the counter-rotating fan until the multiple phase angle differences of each blade are not equal, so as to obtain the 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 angle of the multiple blades until the centroid of the fan blade coincides with the axis of the fan blade.

[0170] This invention modulates the phase angles of multiple blades along the circumferential direction of the fan blades in a counter-rotating fan, thereby reducing the order noise and overall noise generated during blade rotation. By symmetrically adjusting the modulated phase angles of multiple blades, the center of mass of the fan blades is brought to zero. This invention improves the order noise in an axial counter-rotating fan while keeping the center of mass of the fan blades on the axis of rotation, eliminating the need for adjusting the center of mass through counterweights or other means, thus reducing costs and simplifying the overall fan structure.

[0171] In one embodiment, the symmetrical adjustment of the modulated phase angle of the plurality of blades until the centroid of the fan blade coincides with the axial center of the fan blade includes:

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

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

[0174] In one embodiment:

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

[0176] The determination of the zeroing angle includes: finding the zeroing angle that satisfies the optimization formula using the least squares method, and calculating the phase angle α after modulation of the i-th blade. i ′=α i +θsinα i In this case, the optimization formula is: The phase angle after modulation of the i-th blade is calculated to be α. i ′=α i +θcosα i In this case, the optimization formula is: Where N is the number of leaves, α i " is the phase angle after the i-th blade is zeroed out.

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

[0178] Based on different modulation angles, the front blade and the rear blade are modulated respectively. After the centroids of the front blade and the rear blade return 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. The modulation angle includes the front blade modulation angle for modulating the front blade and the rear blade modulation angle for modulating the rear blade.

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

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

[0181] Calculate the time-domain superimposed waveform of the superimposed noise versus time;

[0182] Transform the time-domain superimposed waveform into a frequency-domain waveform;

[0183] Extract order noise from the frequency domain waveform.

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

[0185] Generate the basic phase waveforms of the front blade noise and the rear blade noise with respect to the noise and phase relationship generated by all the front blades, respectively;

[0186] At multiple sampling times, the rotation angle of the front blade is determined based on the rotation speed of the front blade, and the rotation angle of the rear blade is determined based on the rotation speed of the rear blade. The waveform of the front blade noise basis phase waveform after shifting the front blade rotation angle in the rotation direction is taken as the front blade noise sampling time phase waveform, and the waveform of the rear blade noise basis phase waveform after shifting the rear blade rotation angle in the rotation direction is taken as the rear blade noise sampling time phase waveform.

[0187] The phase waveform of the noise sampling moment of the front blade is discretized to obtain the front blade noise column vector, and the phase waveform of the noise sampling moment of the rear blade is discretized to obtain the rear blade noise column vector. The dot product of the noise column vector of the front blade and the noise column vector of the rear blade is used as the superimposed noise at the sampling moment.

[0188] Generate a time-domain superimposed waveform relating superimposed noise to time based on the superimposed noise corresponding to all sampling times.

[0189] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0190] like Figure 12 The diagram shown is a hardware structure schematic of an electronic device according to the present invention, comprising:

[0191] At least one processor 1201; and,

[0192] A memory 1202 is communicatively connected to 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 to enable the at least one of the processors to perform the counter-rotating fan blade modulation method as described above.

[0194] Figure 12 Take a processor 1201 as an example.

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

[0196] The processor 1201, memory 1202, input device 1203 and display device 1204 can be connected by a bus or other means. The figure shows an example of connection by bus.

[0197] The memory 1202, as a non-volatile computer-readable storage medium, 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 embodiments of this application, for example, Figure 1 , Figure 2 The method flow is shown. The processor 1201 executes various functional applications and data processing by running non-volatile software programs, instructions, and modules stored in the memory 1202, thereby implementing the counter-rotating fan blade modulation method in the above embodiments.

[0198] The memory 1202 may include a program storage area and a data storage area. The program storage area may store an operating system and an application program required for at least one function. The data storage area may store data created based on the use of the counter-rotating fan blade modulation method, etc. Furthermore, the memory 1202 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 1202 may optionally include memory remotely located relative to the processor 1201, and these remote memories may be connected via a network to the apparatus performing the counter-rotating fan blade modulation method. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, 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 may include a display screen or other display equipment.

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

[0201] This invention modulates the phase angles of multiple blades along the circumferential direction of the fan blades in a counter-rotating fan, thereby reducing the order noise and overall noise generated during blade rotation. By symmetrically adjusting the modulated phase angles of multiple blades, the center of mass of the fan blades is brought to zero. This invention improves the order noise in an axial counter-rotating fan while keeping the center of mass of the fan blades on the axis of rotation, eliminating the need for adjusting the center of mass through counterweights or other means, thus reducing costs and simplifying the overall fan structure.

[0202] One embodiment of the present invention provides a storage medium that stores computer instructions, which, when executed by a computer, are used to perform all the steps of the aforementioned counter-rotating fan blade modulation method.

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

[0204] One embodiment of the present invention provides a computer program product, including a computer program / instructions, which, when executed by a processor, implements the aforementioned method for bending counter-rotating fan blades.

[0205] An embodiment of the present invention provides a counter-rotating fan, including 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 described above.

[0206] One embodiment of the present invention provides a vehicle including the counter-rotating fan as described above.

[0207] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for modulating the blades of a counter-rotating fan, characterized in that, include: The phase of multiple blades of a counter-rotating fan is modulated until the multiple phase angle differences of each blade are not equal, thereby obtaining the 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 multiple blades are symmetrically adjusted until the centroid of the fan blade coincides with the axis of the fan blade. The front blades of the counter-rotating fan are called front blades, and the rear blades of the counter-rotating fan are called rear blades. The method further includes: modulating the front blades and the rear blades based on different modulation angles; after the centroids of the front blades and the rear blades return to their axial positions, for each modulation angle, calculating the order noise of the superimposed noise of all the front blades and all the rear blades, wherein the modulation angles include the front blade modulation angle for modulating the front blades and the rear blade modulation angle for modulating the rear blades; selecting the front blade modulation angle when the order noise is optimal as the optimal front blade modulation angle, and the rear blade modulation angle as the optimal rear blade modulation angle and outputting it.

2. The method for modulating counter-rotating fan blades according to claim 1, characterized in that, The symmetrical adjustment of the modulated phase angle of the plurality of blades until the centroid of the fan blade coincides with the axial center of the fan blade includes: Select one or more groups of blades from all the blades as the blade groups to be adjusted, each group of blades to be adjusted includes two blades that are axially symmetrical; Determine the zeroing angle. In the same group of blades to be adjusted, increase the zeroing angle of the modulated phase angle of one blade to obtain the corresponding zeroing phase angle, and decrease the zeroing angle of the modulated phase angle of another blade to obtain the corresponding zeroing phase angle. The zeroing phase angles corresponding to the modulated phase angles of the remaining blades outside the group of blades to be adjusted are the same as the modulated phase angles.

3. The method for modulating counter-rotating fan blades according to claim 2, characterized in that: The modulation includes: calculating the equidistant phase angles of each blade in the circumferential direction of the fan blade under uniform distribution conditions, and calculating the modulated phase angle of the i-th blade based on the modulation angle as: α i ′=α i +θsinα i ; or α i ′=α i +θcosα i , where α i Let α be the equidistant phase angle of the i-th blade. i ′ is the modulated phase angle of the i-th blade, and θ is the modulation angle; The determination of the zeroing angle includes: finding the zeroing angle that satisfies the optimization formula using the least squares method, and calculating the phase angle α after modulation of the i-th blade. i ′=α i +θsinα i In this case, the optimization formula is: After calculating the modulation phase angle of the i-th blade, α i ′=α i +θcosα i In this case, the optimization formula is: Where N is the number of leaves, α i " is the phase angle after the i-th blade is zeroed out.

4. The method for modulating counter-rotating fan blades according to claim 1, characterized in that, The calculation of the order noise of the superimposed noise of all the front blades and all the rear blades includes: Calculate the time-domain superimposed waveform of the superimposed noise versus time; Transform the time-domain superimposed waveform into a frequency-domain waveform; Extract order noise from the frequency domain waveform.

5. The method for modulating counter-rotating fan blades according to claim 4, characterized in that, The calculation of the time-domain superposition waveform of the superimposed noise and time relationship between the noise generated by all the front blades and the noise generated by all the rear blades includes: Generate the basic phase waveforms of the front blade noise and the rear blade noise with respect to the noise and phase relationship generated by all the front blades, respectively; At multiple sampling times, the rotation angle of the front blade is determined based on the rotation speed of the front blade, and the rotation angle of the rear blade is determined based on the rotation speed of the rear blade. The waveform of the front blade noise basis phase waveform after shifting the front blade rotation angle in the rotation direction is taken as the front blade noise sampling time phase waveform, and the waveform of the rear blade noise basis phase waveform after shifting the rear blade rotation angle in the rotation direction is taken as the rear blade noise sampling time phase waveform. The phase waveform of the noise sampling time of the front blade is discretized to obtain the front blade noise column vector, and the phase waveform of the noise sampling time of the rear blade is discretized to obtain the rear blade noise column vector. The dot product of the noise column vector of the front blade and the noise column vector of the rear blade is used as the superimposed noise at the sampling time. A time-domain superimposed waveform on the relationship between superimposed noise and time is generated based on the superimposed noise corresponding to all sampling times.

6. A counter-rotating fan blade modulation device, characterized in that, include: A phase angle modulation module is used to modulate the phase of multiple blades of a counter-rotating fan until the phase angle differences of multiple blades are not equal, thereby obtaining the 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 angle of multiple blades until the centroid of the fan blade coincides with the axis of the fan blade. The device includes a front blade of the counter-rotating fan and a rear blade of the counter-rotating fan. The device further includes an order noise optimization module, used to modulate the front and rear blades based on different modulation angles. After ensuring that the centroids of both the front and rear blades return to their axial positions, for each modulation angle, the module calculates the order noise of the superimposed noise of all the front and rear blades. The modulation angles include the front blade modulation angle for modulating the front blades and the rear blade modulation angle for modulating the rear blades. The module selects the front blade modulation angle where the order noise is optimal as the optimal front blade modulation angle and the rear blade modulation angle as the optimal rear blade modulation angle, and outputs these values.

7. 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 executable by at least one of the processors, which enable the at least one of the processors to perform the counter-rotating fan blade modulation method as described in any one of claims 1 to 5.

8. A storage medium, characterized in that, The storage medium stores computer instructions, which, when executed by the computer, are used to perform all the steps of the counter-rotating fan blade modulation method as described in any one of claims 1 to 5.

9. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the method for bending counter-rotating fan blades as described in any one of claims 1 to 5.

10. A counter-rotating fan, characterized in that, It includes 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 in any one of claims 1 to 5.

11. A vehicle, characterized in that, Including the counter-rotating fan as described in claim 10.

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