Multi-scale turbulence generation, regulation and control method and device based on fan matrix

Abstract

The invention relates to the technical field of fluid mechanics and experimental fluid measurement, in particular to a multi-scale turbulence generation, regulation and control method and device based on a fan matrix, the regulation and control device comprises the fan matrix, the fan matrix comprises a plurality of fan groups, and the multiple fan groups are sequentially arranged into a matrix in the longitudinal direction and the transverse direction; each fan set in the fan matrix comprises an adjusting mechanism and fans, the angle adjusting mechanism adjusts the inclination angle of the fans, the position adjusting mechanism adjusts the distance between every two adjacent fans, each fan is provided with a PWM speed regulator, and an outlet of each fan is rotationally provided with a spoiler. The regulation and control method is applied to the regulation and control device, and periodic or random fluctuation can be superposed, so that adjustable turbulence is realized in a relatively large spatial range, and different experimental requirements are met.

Description

Technical Field

[0001] The present invention relates to the field of fluid mechanics and experimental fluid measurement technology, and in particular to a fan matrix-based multi-scale turbulence generation and control method and device. Background Art

[0002] Turbulence is an important topic in fluid mechanics research and engineering applications. Its complex multi-scale vortex structure has a profound impact on many fields such as aircraft, building ventilation, and environmental flow. When studying turbulent characteristics, it is usually necessary to generate flow fields with different turbulence degrees, vortex scale distributions, and energy spectrum characteristics under controllable experimental conditions in order to study the formation mechanism and energy transfer path of turbulence; the fan converts mechanical energy into airflow kinetic energy through blades. When the motor drives the blades to rotate, an interaction force will be generated between the blades and the air, causing the air to accelerate and form an airflow; when the airflow passes through the fan, a series of complex vortices and turbulence will be generated; in the fan matrix, the relative position and angle between each fan will affect the generation, propagation, and interaction of vorticity. The fan speed is one of the important factors affecting the amplitude change of the turbulent energy spectrum of the fan matrix.

[0003] Among the existing methods, wind tunnel tests are mostly used to simulate the effects of turbulent wind parameters. Although traditional wind tunnels can provide a relatively stable flow field, it is difficult to flexibly control the turbulence intensity and vortex structure over a large range. Some passive adjustment methods for simulating turbulent wind include arranging spoilers, honeycomb grids or other passive devices in the wind tunnel that can block or disturb the flow field. However, their adjustment means are limited, and it is difficult to achieve fine control of multi-scale and time-variable turbulence. In addition, how to simultaneously obtain key indicators such as adjustable turbulence intensity and controllable energy spectrum peak, smaller frequency drift, etc. in the same device has always been a difficult problem in experimental fluid mechanics. Summary of the invention

[0004] The purpose of the present invention is to provide a multi-scale turbulence generation and control method and device based on a fan matrix, which can flexibly change the fan speed, spacing, inclination angle and the installation method of the spoiler, and perform periodic or random fluctuations, thereby achieving adjustable turbulence in a larger spatial range to meet different experimental needs.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The multi-scale turbulence generation and control method based on fan matrix includes the following steps:

[0007] S1: Set a set of fan matrix parameters as initial fan matrix parameters, and measure the initial turbulence energy spectrum and initial vorticity distribution generated by the fan matrix;

[0008] S2: Obtain the fan basic speed No, set relevant parameters of the superimposed fluctuation, and calculate the fan variable speed after the superimposed fluctuation. The fan variable speed includes the fan periodic fluctuation speed Nr and the fan random fluctuation speed Ns.

[0009] S3: sending the obtained fan periodic fluctuation speed Nr and fan random fluctuation speed Ns to the PWM speed regulators of multiple fans in sequence, so that the multiple fans rotate at the same speed Nr or Ns, and respectively obtaining the current turbulence energy spectrum and the current vorticity distribution; the current turbulence energy spectrum includes the periodic fluctuation turbulence energy spectrum and the random fluctuation turbulence energy spectrum, and the current vorticity distribution includes the periodic fluctuation vorticity distribution and the random fluctuation vorticity distribution;

[0010] S4: Compare the current turbulence energy spectrum obtained in S3 with the initial turbulence energy spectrum obtained in S1 to determine whether the change in the peak amplitude of the energy spectrum during the turbulence evolution process meets the set target value; if so, save the corresponding fan matrix parameters and related parameters of the superimposed fluctuations and enter S5; if not, return to S2;

[0011] S5: Obtain the current vorticity distribution corresponding to the relevant parameters of the superimposed fluctuation of the fan matrix parameters saved in S4, compare and analyze it with the initial vorticity distribution obtained in S1, and determine whether the current vorticity distribution meets the set requirements; if so, save the corresponding fan matrix parameters and the relevant parameters of the superimposed fluctuations, and enter S6; if not, return to S1 and modify the initial fan matrix parameters;

[0012] S6: Output the fan matrix parameters and related parameters of the superimposed fluctuations that simultaneously meet the requirements that the energy spectrum peak amplitude change reaches the set target value and the vorticity distribution reaches the set requirements.

[0013] Preferably, S2 includes the following steps: if the superimposed fluctuation is set to a periodic fluctuation, the fan basic speed No is obtained, the relevant parameters of the superimposed periodic fluctuation are set to include the fluctuation amplitude A, the fluctuation frequency f, and the fluctuation period t, and the fan speed Nr after the superimposed periodic fluctuation is calculated: Nr = No + A × sin (2 × π × f × t).

[0014] Preferably, the S2 further comprises the following steps:

[0015] If the superimposed fluctuation is set to be a random fluctuation, obtain the fan basic speed No, and calculate the fan speed Ns after superimposing the random fluctuation, Ns=No+Nm, where Nm is the random fluctuation speed, and the random fluctuation is generated by a random number generator or a random signal transmitter.

[0016] Preferably, S1 comprises the following steps: the fan matrix parameters include fan inclination parameters, fan arrangement spacing parameters and jet direction parameters as well as spoiler size parameters, spoiler position parameters and spoiler angle parameters.

[0017] Preferably, the energy spectrum peak amplitude change in S4 is set to ≥30%, the frequency drift is set to <±10%, and the vortex distribution setting requirements in S5 are that the current vortex distribution quantity adjustment range is 5% to 30%, and the vortex core diameter adjustment range in the current vortex distribution is 5% to 30%.

[0018] A multi-scale turbulence generation and control device based on a fan matrix is ​​applied to the above-mentioned multi-scale turbulence generation and control method based on a fan matrix, including a fan matrix, the fan matrix includes multiple fan groups, and the multiple fan groups are arranged in sequence into a matrix in the longitudinal and transverse directions. Each fan group in the fan matrix includes an adjustment mechanism and a fan, the adjustment mechanism includes an angle adjustment mechanism and a position adjustment mechanism, the angle adjustment mechanism can adjust the fan inclination angle, and the position adjustment mechanism can adjust the distance between two adjacent fans. A PWM speed regulator is installed on each fan, and a spoiler is rotatably provided at each fan outlet, and the spoiler adjusts the inclination angle through the inclination adjustment mechanism.

[0019] Preferably, the fan matrix can simulate and adjust turbulence of different scales, and the turbulence simulation adjustment range is 5% to 30%.

[0020] Preferably, the fan inclination angle adjustment range is 0° to 30°, the distance adjustment range between two adjacent fans is 0 to 10 mm, the spoiler rotation adjustment angle is 0° to 60°, and the fan speed adjustment range is 0 to 20000 rpm.

[0021] Preferably, the adjustment mechanism also includes a shell, and the shell is installed with a position adjustment mechanism, the position adjustment mechanism includes two groups of matching holes respectively opened on both sides of the shell, each group of matching holes includes a plurality of adjustment holes spaced apart along the side of the shell, and the guide rods fixedly arranged in the middle of both sides of the fan correspond to the two groups of matching holes on both sides of the shell respectively, and the guide rods are correspondingly connected to one of the adjustment holes in a group of matching holes.

[0022] Preferably, the inclination adjustment mechanism includes multiple groups of vertically arranged first connecting rods and multiple groups of second connecting rods arranged in parallel and corresponding to the multiple groups of first connecting rods. The number of groups of first connecting rods and second connecting rods is the same as the number of rows in the fan matrix. The two fixed rods in each group of first connecting rods are respectively fixed on both sides of the fan group, and one end of the spoiler close to the fan group is rotatably connected to the fixed rod, and the two sides of the middle part of the spoiler are hinged to the two adjustment rods in the corresponding group of second connecting rods.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The fan matrix-based multi-scale turbulence generation and control device provided by the present invention utilizes a combination of spoilers and fan arrays to simultaneously change the vortex scale distribution and energy spectrum characteristics to obtain multi-scale turbulence; it achieves regulation from low turbulence to high turbulence, has good scalability and repeatability, and meets a wide range of experimental research and engineering test needs.

[0025] The multi-scale turbulence generation and control device based on the fan matrix provided by the present invention can flexibly change the fan speed, spacing, inclination angle and the installation method of the spoiler, and perform periodic or random fluctuations, thereby realizing adjustable turbulence in a larger spatial range and meeting different experimental needs.

[0026] The multi-scale turbulence generation and control method based on fan matrix provided by the present invention is applied to the above-mentioned multi-scale turbulence generation and control device based on fan matrix. By superimposing periodic or random fluctuations, it can simulate the variable turbulence characteristics in actual working conditions, and sample and analyze the flow field to verify that the control method can change the peak amplitude of the turbulent flow field energy spectrum by ≥30% and the frequency drift by <±10%, and can accurately measure and control key turbulence parameters such as vortex core diameter and vortex distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a control flow chart of the multi-scale turbulence generation and regulation method based on the fan matrix of the present invention;

[0028] Figure 2 This is a flow chart of speed control when superimposed fluctuations are performed in the present invention;

[0029] Figure 3 This is a schematic diagram of the fan matrix arrangement structure in the multi-scale turbulence generation and control device based on the fan matrix of the present invention;

[0030] Figure 4 It is a schematic diagram of the connection structure between the spoiler and the fan of the present invention;

[0031] Figure 5 It is a schematic diagram of the connection between the tilt angle adjustment mechanism, the spoiler and the fan of the present invention.

[0032] Figure numerals: 1, fan assembly; 2, housing; 21, adjustment hole; 4, spoiler; 5, fixing rod; 6, adjustment rod. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the following description of the invention, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating directions or positional relationships, are based on directions or positional relationships shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. The term "connection" only indicates the connection between devices and has no special meaning.

[0035] In addition, the technical fields and installation methods involved in the embodiments of the present invention described below can be combined with each other as long as there is no conflict between them.

[0036] See also Figure 3-Figure 5 A multi-scale turbulence generation and control device based on a fan matrix includes a fan matrix, the fan matrix includes multiple fan groups 1, and the multiple fan groups 1 are arranged in a matrix structure in the longitudinal and transverse directions. The size of the fan matrix is ​​2.5m×1.875m, and the number of fan groups 1 can be adjusted according to specific usage requirements; in this embodiment, the fan matrix includes 300 fan groups 1, and the 300 fan groups 1 are arranged in a matrix group of 15 rows×20 columns in the longitudinal and transverse directions.

[0037] Each fan group 1 in the fan matrix includes an adjustment mechanism and a fan, the adjustment mechanism includes a shell 2 and an angle adjustment mechanism, a position adjustment mechanism is installed on the shell 2, the position adjustment mechanism includes two groups of matching holes respectively opened on both sides of the shell 2, each group of matching holes includes a plurality of adjustment holes 21 spaced apart along the side of the shell 2, the two sides of the fan correspond one to one with the two groups of matching holes on both sides of the shell 2 through a guide rod fixedly arranged in the middle, the guide rod can be connected to one of the adjustment holes 21 in a group of matching holes, the connection position of the fan and the regulating hole can be manually adjusted to adjust the relative position of the fan and the adjustment mechanism, thereby adjusting the spacing between two adjacent fan groups 1, the spacing adjustment range of two adjacent fans in the horizontal direction or the vertical direction is 0 to 10 mm, so that the airflows between the multiple fans interfere with each other to form vortices and shear layers; the angle adjustment mechanism includes an angle adjustment motor (not shown in the figure) and a driving gear rotatably arranged on the shell 2 and a driven gear fixedly arranged on the guide rod, the driving gear The wheel is meshed and connected with the driven gear, and the output shaft of the angle adjustment motor is fixedly connected with the driving gear. When the angle adjustment motor is started, the driving gear drives the driven gear to rotate, thereby adjusting the fan inclination angle. The angle adjustment mechanism can adjust the fan inclination angle, and the fan inclination angle adjustment range is 0°~30°, thereby adjusting the fan jet direction, affecting the wind pressure and air volume, and adjusting the jet direction of multiple fans in the fan matrix can change the distribution of the vortex structure and the shear layer flow field; each fan is installed with a PWM speed regulator, which is a pulse width modulation speed regulator. It is a device that uses pulse width modulation technology to achieve motor speed regulation. The PWM speed regulator is an existing technology and will not be repeated here; each fan can adjust the fan speed through the PWM speed regulator, and its speed adjustment range is 0~20000rpm to adjust the airflow injection intensity; the inclination angle, arrangement spacing, jet direction of the fans in the multiple fan groups 1 and the interaction between the fans can induce the generation of complex vortex structures and shear layer flow fields.

[0038] Each fan outlet is rotatably provided with a spoiler 4, the width of the spoiler 4 is 0.5 to 1 times the fan diameter, the shape and size of the spoiler 4 can be adjusted according to specific test requirements, common spoilers 4 include plane, arc and sawtooth shapes, etc., the rotation adjustment angle of the spoiler 4 disclosed in this embodiment is 0° to 60°, the spoiler 4 is 5 cm away from the fan blade outlet, the length and width of the spoiler 4 are the same as the fan diameter, and the angle between the spoiler 4 and the vertical plane where the fan outlet is located can be adjusted by an inclination adjustment mechanism, and the inclination adjustment mechanism includes a plurality of groups of vertically arranged first connecting rods and a plurality of groups of first connecting rods respectively connected to the plurality of groups of first connecting rods. The connecting rod is arranged in parallel with the corresponding second connecting rod, the number of groups of the first connecting rod and the second connecting rod is the same as the number of rows in the fan matrix. In this embodiment, the number of groups of the first connecting rod and the second connecting rod is 15 groups. The two fixed rods 5 in each group of the first connecting rods are respectively fixed on both sides of the fan group 1, and the end of the spoiler 4 close to the fan group 1 is rotatably connected to the fixed rod 5, and the two sides of the middle part of the spoiler 4 are hinged with the two adjustment rods 6 in the corresponding group of the second connecting rods. Adjusting the up and down movement of the second connecting rod can control the angle change of the spoiler 4 to trigger vortex structures of different scales. At the same time, the local shear and rotation effects of the fan jet are cooperated to realize the controllable generation of multi-scale turbulence.

[0039] Among them, the fan matrix disclosed in this embodiment can be simulated and adjusted from low turbulence to high turbulence, wherein the low turbulence is about 5% and the high turbulence is about 30%; specifically, when the basic fan speed is 3000rpm and the angle of the spoiler 4 is 15°, the rotating fan blades will cut the airflow, which is easy to cause turbulence in the airflow. The turbulence of the flow field caused by the fan matrix is ​​measured to be about 5%, which is low turbulence; when the basic fan speed is 6000rpm and the angle of the spoiler 4 is 45°, the turbulence of the flow field caused by the fan matrix is ​​measured to be about 30%, which is high turbulence.

[0040] See also Figure 1-Figure 2 , a multi-scale turbulence generation and control method based on a fan matrix, applied to the above-mentioned multi-scale turbulence generation and control device based on a fan matrix, comprises the following steps:

[0041] S1: Set a set of fan matrix parameters as initial fan matrix parameters, and measure the initial turbulence energy spectrum and initial vorticity distribution generated by the fan matrix;

[0042] Among them, the fan matrix parameters include fan inclination angle, fan arrangement spacing and jet direction, as well as the size, position, angle and other parameters of the spoiler 4. This group of parameters can induce complex vortex structures and shear layer flow fields. The initial fan matrix parameters in this embodiment are: the fan inclination angle is 0°, at this time the jet direction is straight ahead, the spacing between adjacent upper and lower fans and the spacing between adjacent left and right fans are both 0.5 times the fan diameter, the spoiler 4 is 5 cm away from the fan blade outlet, the length and width of the spoiler 4 are the same as the fan diameter, and the spoiler 4 has an inclination angle of 30°. Based on the above test parameters, experiments are carried out to obtain the initial turbulent energy spectrum and initial vorticity distribution.

[0043] S2: Obtain the fan basic speed No, set relevant parameters of the superimposed fluctuation, and calculate the fan variable speed after the superimposed fluctuation. The fan variable speed includes the fan periodic fluctuation speed Nr and the fan random fluctuation speed Ns.

[0044] Specifically, the corresponding fan speed in the initial fan matrix parameters is obtained as the basic speed No. If the superimposed fluctuation is set to be a periodic fluctuation, the relevant parameters of the superimposed fluctuation are set to include the fluctuation amplitude A, the fluctuation frequency f, and the fluctuation period t, and the fan periodic fluctuation speed Nr after the superimposed periodic fluctuation is calculated:

[0045] Nr=No+A×sin(2×π×f×t)

[0046] If the superimposed fluctuation is a random fluctuation, it is used to simulate the randomness of the fan speed. The amplitude and frequency of the random fluctuation can be set according to actual needs. The fan basic speed No is obtained, and the fan random fluctuation speed Ns after superimposing the random fluctuation is calculated:

[0047] Ns=No+Nm

[0048] Among them, Nm is the random fluctuation speed. The random fluctuation can be generated by a random number generator or a random signal transmitter. The generated random fluctuation is superimposed on the basic speed to obtain the actual speed of each fan; this actual speed can be output to the PWM speed regulator in real time to adjust the operating state of the fan.

[0049] In the superimposed periodic fluctuation or random fluctuation in this embodiment, the fluctuation amplitude is between 1% and 10%, and the fluctuation frequency is between 0.1 and 10 Hz.

[0050] S3: Send the obtained fan periodic fluctuation speed Nr and fan random fluctuation speed Ns to the PWM speed regulators of multiple fans in sequence, so that the multiple fans run at the same speed Nr or Ns, and obtain the current turbulence energy spectrum and current vorticity distribution after the fan matrix superimposed fluctuation; the current turbulence energy spectrum includes the periodic fluctuation turbulence energy spectrum and the random fluctuation turbulence energy spectrum, and the current vorticity distribution includes the periodic fluctuation vorticity distribution and the random fluctuation vorticity distribution;

[0051] Specifically, a test area is set up downstream of the fan matrix to ensure that at least 80% of the core test area is covered; the sampling points are reasonably arranged according to the size and shape of the test area to ensure the comprehensiveness and accuracy of the data, and random fluctuations or periodic fluctuations are superimposed on the overall layout of the initial fan matrix, so that the fans rotate at the fan periodic fluctuation speed Nr and the fan random fluctuation speed Ns, respectively, and the periodic fluctuation turbulence energy spectrum and the random fluctuation turbulence energy spectrum are respectively obtained and used as the current turbulence energy spectrum.

[0052] Furthermore, particle image velocimetry (PIV) technology is used to scatter tracer particles in the test area, a laser light source is used to illuminate the particles, the movement trajectory of the particles over time is recorded, and the velocity field is calculated using image processing technology to deduce the current vorticity distribution. The current vorticity distribution corresponds to the periodic fluctuating vorticity distribution obtained when the fan rotates at the fan's periodic fluctuating speed Nr, and the randomly fluctuating vorticity distribution obtained when the fan rotates at the fan's randomly fluctuating speed Ns.

[0053] Specifically, PIV technology is used to obtain the velocity field after regulation and perform velocity measurement to capture all the characteristics of turbulence. The collected data is preprocessed, such as denoising and filtering, to improve data quality. The preprocessed data is Fourier transformed, and the energy density at different frequencies is calculated to obtain the current turbulence energy spectrum after regulation.

[0054] S4: Compare the current turbulence energy spectrum obtained in S3 with the initial turbulence energy spectrum obtained in S1 to determine whether the change in the peak amplitude of the energy spectrum during the turbulence evolution process meets the set target value; if so, save the corresponding fan matrix parameters and related parameters of the superimposed fluctuations and enter S5; if not, return to S2.

[0055] Specifically, in this embodiment, the set amplitude variation of the energy spectrum peak value in the current target value is set to be ≥30%, and the set frequency drift is set to be <±10%.

[0056] Among them, the current turbulence energy spectrum peak value obtained after S4 fan speed regulation is compared with the turbulence energy spectrum peak value obtained in S1, and the change in the peak amplitude of the current turbulence energy spectrum after regulation is calculated. In this embodiment, a percentage is used to represent the size of the change. The change in the peak amplitude of the current turbulence energy spectrum is calculated, and it is calculated whether it satisfies the set amplitude change ≥30%; if it does, enter S5; if it does not, return to S2, reset the relevant parameters of the superimposed fluctuation, and recalculate the fan periodic fluctuation speed Nr and the fan random fluctuation speed Ns after the superimposed fluctuation.

[0057] Furthermore, by analyzing the initial turbulence energy spectrum and the turbulence energy spectra obtained after multiple adjustments of S4, the energy distribution at different frequencies is observed, the range and characteristics of the frequency drift are determined, and the value of the frequency drift is calculated. The frequency drift under multiple different adjustment states is compared. In this embodiment, the change in frequency drift is expressed by its relative frequency change rate, and the frequency drift is observed to be <±10%.

[0058] S5: Obtain the current vorticity distribution corresponding to the relevant parameters of the superimposed fluctuation of the fan matrix parameters saved in S4, compare and analyze it with the initial vorticity distribution obtained in S1, and judge whether the current vorticity distribution meets the set requirements; if so, save the corresponding fan matrix parameters and the relevant parameters of the superimposed fluctuations, and enter S6; if not, return to S1, reset the initial fan matrix parameters to generate turbulence;

[0059] Specifically, the vorticity distribution reveals the distribution number of turbulent eddies of different scales and the vortex core diameters of turbulent eddies of different scales, wherein turbulent eddies of different scales include large-scale turbulent eddies and small-scale turbulent eddies, and the setting requirements for the distribution number of turbulent eddies of different scales and the vortex core diameters of turbulent eddies of different scales are set according to the test requirements. In this embodiment, the adjustment range of the current vortex distribution number is 5% to 30%, and the adjustment range of the vortex core diameters of turbulent eddies of different scales in the current vortex distribution is 5% to 30%; the fan matrix parameters and related parameters of the superimposed fluctuations saved in S4 are retrieved to obtain the current vorticity distribution corresponding to the group of parameters, and the data statistical analysis is performed on it and the initial vorticity distribution obtained by S1 respectively, the initial vorticity distribution and the current vorticity distribution can be observed by flow field visualization technology, and the statistical quantities such as the mean and variance of the initial vorticity distribution and the current vorticity distribution are calculated to observe the vorticity distribution law after the superimposed fluctuations.

[0060] If the distribution number of turbulent eddies of different scales and the vortex core diameter in the current vorticity distribution meet the set requirements, enter S6; if the distribution number of turbulent eddies of different scales and the vortex core diameter in the current vorticity distribution do not meet the set requirements, return to S1, modify the initial fan matrix parameters, reset the initial fan matrix parameters, and perform turbulent control and generation.

[0061] S6: Output the fan matrix parameters and related parameters of the superimposed fluctuations that simultaneously meet the requirements that the energy spectrum peak amplitude change reaches the set target value and the vorticity distribution reaches the set requirements.

[0062] Specifically, the fan matrix parameters and related parameters of the superimposed fluctuations corresponding to the energy spectrum peak amplitude change reaching the set target value and the vorticity distribution reaching the set requirements are satisfied at the same time, indicating that the multi-scale turbulence generation and control device based on the fan matrix can achieve fine control of multi-scale variable turbulence through the above method, and at the same time, adjustable turbulence, controllable energy spectrum peak and smaller frequency drift index can be obtained in the device.

[0063] Specifically, the output fan matrix parameters include fan inclination parameters, fan arrangement spacing parameters and jet direction parameters, as well as size parameters of spoiler 4, position parameters of spoiler 4 and angle parameters of spoiler 4. The relevant parameters of superimposed fluctuations include the fan periodic fluctuation speed Nr after superimposed periodic fluctuations and the fan random fluctuation speed Ns after superimposed random fluctuations and its corresponding random fluctuation speed Nm.

[0064] The fan matrix-based multi-scale turbulence generation and control device provided by the present invention utilizes a combination of a spoiler 4 and a fan array to simultaneously change the vortex scale distribution and energy spectrum characteristics to obtain multi-scale turbulence; it achieves regulation from low turbulence to high turbulence, has good scalability and repeatability, and meets a wide range of experimental research and engineering test needs.

[0065] The multi-scale turbulence generation and control device based on the fan matrix provided by the present invention can flexibly change the fan speed, spacing, inclination angle and the installation method of the spoiler 4, and perform periodic or random fluctuations, thereby realizing adjustable turbulence in a larger spatial range to meet different experimental needs.

[0066] The multi-scale turbulence generation and control method based on fan matrix provided by the present invention is applied to the above-mentioned multi-scale turbulence generation and control device based on fan matrix. By superimposing periodic or random fluctuations, it can simulate the variable turbulence characteristics in actual working conditions, and sample and analyze the flow field to verify that the control method can change the peak amplitude of the turbulent flow field energy spectrum by ≥30% and the frequency drift by <±10%, and can accurately measure and control key turbulence parameters such as vortex core diameter and vortex distribution.

Claims

1. A multi-scale turbulence generation and control method based on a fan matrix, characterized in that: The steps include: S1: Set a set of fan matrix parameters as initial fan matrix parameters, and measure the initial turbulence energy spectrum and initial vorticity distribution generated by the fan matrix; S2: Obtain the fan basic speed No, set relevant parameters of the superimposed fluctuation, and calculate the fan variable speed after the superimposed fluctuation. The fan variable speed includes the fan periodic fluctuation speed Nr and the fan random fluctuation speed Ns. S3: sending the obtained fan periodic fluctuation speed Nr and fan random fluctuation speed Ns to the PWM speed regulators of multiple fans in sequence, so that the multiple fans rotate at the same speed Nr or Ns, and respectively obtaining the current turbulence energy spectrum and the current vorticity distribution; the current turbulence energy spectrum includes the periodic fluctuation turbulence energy spectrum and the random fluctuation turbulence energy spectrum, and the current vorticity distribution includes the periodic fluctuation vorticity distribution and the random fluctuation vorticity distribution; S4: Compare the current turbulence energy spectrum obtained in S3 with the initial turbulence energy spectrum obtained in S1 to determine whether the change in the peak amplitude of the energy spectrum during the turbulence evolution process meets the set target value; if so, save the corresponding fan matrix parameters and related parameters of the superimposed fluctuations and enter S5; if not, return to S2; S5: Obtain the current vorticity distribution corresponding to the relevant parameters of the superimposed fluctuation of the fan matrix parameters saved in S4, compare and analyze it with the initial vorticity distribution obtained in S1, and determine whether the current vorticity distribution meets the set requirements; if so, save the corresponding fan matrix parameters and the relevant parameters of the superimposed fluctuations, and enter S6; if not, return to S1 and modify the initial fan matrix parameters; S6: Output the fan matrix parameters and related parameters of the superimposed fluctuations that simultaneously meet the requirements that the energy spectrum peak amplitude change reaches the set target value and the vorticity distribution reaches the set requirements.

2. The multi-scale turbulence generation and control method based on fan matrix according to claim 1 is characterized in that: The S2 includes the following steps: if the superimposed fluctuation is set to a periodic fluctuation, the fan basic speed No is obtained, the relevant parameters of the superimposed periodic fluctuation are set to include the fluctuation amplitude A, the fluctuation frequency f, and the fluctuation period t, and the fan speed Nr after the superimposed periodic fluctuation is calculated: Nr = No + A × sin (2 × π × f × t).

3. The multi-scale turbulence generation and control method based on fan matrix according to claim 2 is characterized in that: The S2 further comprises the following steps: If the superimposed fluctuation is set to be a random fluctuation, obtain the fan basic speed No, and calculate the fan speed Ns after superimposing the random fluctuation, Ns=No+Nm, where Nm is the random fluctuation speed, and the random fluctuation is generated by a random number generator or a random signal transmitter.

4. The multi-scale turbulence generation and control method based on fan matrix according to claim 1 is characterized in that: The S1 comprises the following steps: the fan matrix parameters include fan inclination parameters, fan arrangement spacing parameters and jet direction parameters as well as spoiler size parameters, spoiler position parameters and spoiler angle parameters.

5. The multi-scale turbulence generation and control method based on fan matrix according to claim 1 is characterized in that: In S4, the energy spectrum peak amplitude change is set to ≥30%, and the frequency drift is set to <±10%. In S5, the vortex distribution setting requirements are that the current vortex distribution quantity adjustment range is 5% to 30%, and the vortex core diameter adjustment range in the current vortex distribution is 5% to 30%.

6. A multi-scale turbulence generation and control device based on a fan matrix, applied to the multi-scale turbulence generation and control method based on a fan matrix according to any one of claims 1 to 5, characterized in that: The invention comprises a fan matrix, which comprises a plurality of fan groups, and the plurality of fan groups are arranged in sequence in a matrix in the longitudinal and transverse directions. Each fan group in the fan matrix comprises an adjustment mechanism and a fan, and the adjustment mechanism comprises an angle adjustment mechanism and a position adjustment mechanism. The angle adjustment mechanism can adjust the fan inclination angle, and the position adjustment mechanism can adjust the distance between two adjacent fans. A PWM speed regulator is installed on each fan, and a spoiler is rotatably provided at each fan outlet, and the inclination angle of the spoiler is adjusted by the inclination adjustment mechanism.

7. The multi-scale turbulence generation and control device based on fan matrix according to claim 6 is characterized in that: The fan matrix can simulate and adjust turbulence of different scales, and the turbulence simulation adjustment range is 5% to 30%.

8. The multi-scale turbulence generation and control device based on fan matrix according to claim 6 is characterized in that: The fan inclination angle adjustment range is 0° to 30°, the distance adjustment range between two adjacent fans is 0 to 10 mm, the spoiler rotation adjustment angle is 0° to 60°, and the fan speed adjustment range is 0 to 20000 rpm.

9. The multi-scale turbulence generation and control device based on fan matrix according to claim 6, characterized in that: The adjustment mechanism also includes a shell, and the shell is installed with a position adjustment mechanism. The position adjustment mechanism includes two groups of matching holes respectively opened on both sides of the shell, each group of matching holes includes a plurality of adjustment holes spaced apart along the side of the shell, and guide rods fixedly arranged in the middle of both sides of the fan correspond to the two groups of matching holes on both sides of the shell respectively, and the guide rods are correspondingly connected to one of the adjustment holes in a group of matching holes.

10. The multi-scale turbulence generation and control device based on fan matrix according to claim 6, characterized in that: The tilt adjustment mechanism includes multiple groups of vertically arranged first connecting rods and multiple groups of second connecting rods arranged in parallel and corresponding to the multiple groups of first connecting rods. The number of groups of first connecting rods and second connecting rods is the same as the number of rows in the fan matrix. The two fixed rods in each group of first connecting rods are respectively fixed on both sides of the fan group, and one end of the spoiler close to the fan group is rotatably connected to the fixed rod, and the two sides of the middle part of the spoiler are hinged to the two adjustment rods in the corresponding group of second connecting rods.

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