Air volume monitoring method and system of centrifugal fan

Abstract

The invention relates to the technical field of air conditioning treatment, in particular to an air volume monitoring method and system for a centrifugal ventilator. The method comprises the steps that the difference between all belt tension data obtained through real-time monitoring data and experiment monitoring data is analyzed; calculating the deviation degree of the air volume value of the real-time monitoring data measured based on the static pressure method under different frequencies, and obtaining the real-time air volume value; based on the fluctuation degree of the wind speed data in all the wind speed sensors, the disordered distribution condition of the fluctuation degree calculated by all the wind speed sensors and the average distribution condition of the fluctuation degree calculated at all the collection moments are utilized, the reliability of real-time wind quantity measurement based on the wind speed method is obtained, and the real-time wind quantity is determined; and the final air volume of the centrifugal fan is determined by combining the air volume values measured in real time through the static pressure method and the air speed method and the deviation degree and reliability of the respective measurement methods. The invention aims to integrate the results of the static pressure method and the wind speed method and improve the overall accuracy and reliability of the air volume measurement.

Description

Technical Field

[0001] This application relates to the technical field of air conditioning treatment, and particularly relates to a method and system for monitoring the air volume of a centrifugal fan. Background Art

[0002] In modern industrial production and commercial operations, centrifugal fans, as key equipment, are widely used in ventilation, air change, dust removal and other systems. However, at present, the air volume monitoring of centrifugal fans faces many challenges. Traditional methods such as the pitot tube method, orifice flowmeter method, anemometer method, and pitot tube - micro - pressure gauge combination method have many deficiencies and are difficult to meet the requirements of high precision, real - time performance, and long - term stability in industrial production. There is an urgent need for an advanced air volume monitoring method to solve these problems and provide strong support for the efficient operation of centrifugal fans and the optimization of system performance.

[0003] In practical applications, the operating conditions of centrifugal fans are complex and diverse, and their air volume is affected by many factors, such as fan speed, blade angle, pipeline resistance, environmental temperature and humidity, etc. Traditional monitoring methods show obvious limitations when dealing with these complex operating conditions. For example, the pitot tube method is easily affected by the airflow disturbance in the pipeline, resulting in inaccurate measurement results; the orifice flowmeter method has high installation and maintenance costs and will increase the pipeline resistance; the measurement accuracy of the anemometer method is easily interfered by environmental factors and requires frequent calibration and maintenance; when measuring a belt - type centrifugal fan by the static pressure method, it will be affected by the degree of belt wear, resulting in low measurement accuracy.

[0004] The deficiencies of these traditional methods not only affect the accuracy of air volume monitoring but also limit the real - time grasp and timely adjustment of the operating state of centrifugal fans, and are difficult to meet the requirements of efficient, precise, and intelligent equipment management in modern industrial production. Summary of the Invention

[0005] To solve the above - mentioned technical problems, this application provides a method and system for monitoring the air volume of a centrifugal fan, and the specific technical solutions adopted are as follows: In a first aspect, an embodiment of this application provides a method for monitoring the air volume of a centrifugal fan, and the method includes the following steps: Obtain the air volume - static pressure curve obtained from experiments on the fan at different frequencies; obtain the air volume measurement deviation values measured by the static pressure method obtained from experiments on the belt at different degrees of wear; analyze the differences between the real - time monitoring data and all the belt tension data obtained from the experimental monitoring data, and screen out multiple experimental monitoring data with belt conditions similar to the real - time monitoring data at different frequencies of the fan, so as to calculate the deviation degree of the air volume value measured by the static pressure method based on the real - time monitoring data at different frequencies; and obtain the air volume value in the air volume - static pressure curve corresponding to the static pressure value measured by the static pressure method based on the real - time monitoring data at the corresponding frequency. Determine the wind speed stability based on the fluctuation degree of the wind speed data in all wind speed sensors; determine the distribution uniformity by using the chaotic distribution of the fluctuation degrees calculated by all wind speed sensors and the average distribution of the fluctuation degrees calculated at all acquisition moments; positively fuse the wind speed stability index and the distribution uniformity to obtain the reliability of real-time air volume measurement based on the wind speed method; determine the air volume at the air outlet measured in real time based on the wind speed method by using the average wind speed at the current moment and the cross-sectional area corresponding to the measurement position of the wind speed sensor. Determine the final air volume of the centrifugal fan by integrating the air volume values measured in real time by the static pressure method and the wind speed method, as well as the deviation degrees and reliabilities of their respective measurement methods.

[0006] Preferably, the method for screening out multiple experimental monitoring data with belt conditions similar to the real-time monitoring data of the fan at different frequencies is as follows: Determine the similarity of belt wear degree between the real-time monitoring data and any one of the experimental monitoring data based on the difference between all the belt tension data obtained from the real-time monitoring data and the experimental monitoring data at the same fan frequency. Take the experimental monitoring data with the similarity of belt wear degree greater than the preset similarity threshold as the experimental monitoring data with belt conditions similar to the real-time monitoring data.

[0007] Preferably, the method for determining the similarity of belt wear degree is as follows: Calculate the normalized value of the cumulative sum of the differences between all the belt tension data obtained from the real-time monitoring data and any one of the experimental monitoring data at the same fan frequency. Take the difference between the value 1 and the normalized value as the similarity of belt wear degree between the real-time monitoring data and any one of the experimental monitoring data at the same fan frequency.

[0008] Preferably, the method for calculating the deviation degree is as follows: Take the normalized value of the average of the air volume measurement deviation values corresponding to all the experimental monitoring data with belt conditions similar to the real-time monitoring data at the same frequency as the deviation degree of the air volume value measured by the static pressure method based on the real-time monitoring data at the same frequency.

[0009] Preferably, the method for determining the wind speed stability is as follows: calculate the variance value of all the wind speed data of each wind speed sensor during the acquisition period, take the reciprocal of the average value of the variance values calculated by all the wind speed sensors and then normalize it to obtain the wind speed stability.

[0010] Preferably, the method for determining the distribution uniformity is as follows: Take the variance of the variance values calculated by all the wind speed sensors as the first wind speed uniformity index; Take the reciprocal of the wind speed variance of all wind speed sensors at each acquisition moment and normalize it as the wind speed uniformity at that moment. Take the average value of the wind speed uniformity at all moments as the second wind speed uniformity index; Take the average value of the first and second wind speed uniformity indexes as the distribution uniformity.

[0011] Preferably, the reliability is positively correlated with the wind speed stability and the distribution uniformity respectively.

[0012] Preferably, the method for determining the air volume of the air outlet measured in real time based on the wind speed method is as follows: Multiply the mean value of the wind speed values of all wind speed sensors collected at the current moment by the cross-sectional area corresponding to the measurement position of the wind speed sensor to obtain the air volume of the air outlet measured in real time based on the wind speed method.

[0013] Preferably, the method for determining the air volume of the final centrifugal ventilator is as follows: In the formula, Pw represents the air volume of the final centrifugal ventilator obtained by the comprehensive static pressure method and the wind speed method, PL represents the deviation degree of the air volume value measured by the static pressure method based on the real-time monitoring data, Kf represents the reliability of measuring the air volume based on the wind speed method, Fc represents the air volume value measured in real time based on the static pressure method, and Fv represents the air volume of the air outlet measured in real time based on the wind speed method.

[0014] In a second aspect, another embodiment of the present application further provides an air volume monitoring system for a centrifugal ventilator, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the air volume monitoring method for a centrifugal ventilator described in any one of the above.

[0015] The present application has at least the following beneficial effects: This application determines the wear condition by monitoring the change in belt tension, and through repeated experimental analysis of the influence of different wear degrees on the measurement deviation of the static pressure method, it enables an understanding of the influence law of belt wear on the measurement result in advance, so as to make corrections in actual monitoring and improve the measurement reliability. According to the similarity calculation between the collected tension data sequence and the experimental data, the deviation degree of the air volume value measured based on the static pressure method for the real-time data is obtained, providing a correction basis for accurately obtaining the air volume value subsequently and effectively dealing with the measurement deviation problem caused by belt wear. By calculating the variance of different wind speed variances as the first uniformity index, and calculating the variance of the wind speed differences of each sensor at the same moment and normalizing and averaging to obtain the second uniformity index, and then taking the average of the two to obtain the overall distribution uniformity index, it comprehensively reflects the uniformity of the air volume at the outlet of the centrifugal fan, providing a key basis for accurately evaluating the measurement reliability of the wind speed method. Finally, by integrating the results of the static pressure method and the wind speed method, considering their respective influencing factors, giving full play to the advantages of the two methods and making up for the deficiencies of a single method, the overall accuracy and reliability of the air volume measurement are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 It is a flowchart of a method for monitoring the air volume of a centrifugal fan provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Embodiment 1 A method for monitoring the air volume of a centrifugal fan provided by an embodiment of the present application is specifically referred to Figure 1 , and the method includes the following steps: Step : Data acquisition.

[0019] This application combines the static pressure method and the wind speed method to obtain the measurement results based on the static pressure method and the wind speed method. By comprehensively using a variety of air volume detection methods, the measurement result of the air volume of the centrifugal fan can be accurately obtained. Therefore, the relevant method measurement parameters for data acquisition in this application are as follows: Among them, the hot-wire anemometer directly measures the wind speed at the distribution points of a certain cross-section, and after averaging, the air volume is calculated from the average wind speed and the cross-sectional area. The static pressure drop method uses the relationship between the static pressure difference at the inlet section of the fan and the air volume, and the air volume of the fan can be calculated by measuring the static pressure difference.

[0020] Therefore, first place the wind speed sensor at the air outlet of the centrifugal fan to measure the wind speed. Obtain the cross-sectional area S of the air outlet corresponding to the installation position of the wind speed sensor.

[0021] The static pressure difference at the inlet and outlet of the centrifugal fan is measured using a pressure difference sensor. At the same time, since this application uses a belt-driven centrifugal fan, it is necessary to analyze the influence of the belt wear degree on the measurement result. Therefore, a belt tension measuring instrument is installed to collect belt tension data.

[0022] Therefore, during monitoring, a monitoring data vector H = {U, E, Y} is obtained at each monitoring moment, where U = {V1, V2, V3, …, Vn}, and V1, V2, V3, Vn respectively represent the wind speed values obtained by the 1st, 2nd, 3rd, …, nth installed wind speed sensors. In this embodiment, n = 8, that is, 8 wind speed sensors are evenly placed at the same cross-sectional position at the air outlet to collect the wind speed; E represents the static pressure difference; Y = {Y1, Y2, Y3, …, Ym}, and Y1, Y2, Y3, Ym respectively represent the belt tension data obtained by the 1st, 2nd, 3rd, …, mth belt tension measuring instruments on the belt of the belt-driven centrifugal fan. In this embodiment, m = 3, that is, three belt tension measuring instruments are evenly placed on the conveyor belt to collect belt tension data. In this embodiment, the above data is collected once per second, and the collection duration is set by the implementer according to the actual situation. In this embodiment, it is set as the data within the past 1 hour before the current collection moment.

[0023] Step : Measure the air volume in real time based on the static pressure method.

[0024] Large step logic: Analyze the influence degree of belt wear on the air volume measurement by the static pressure method through multiple experimental data analyses. The specific expansion is as follows: 1. Obtain the air volume-static pressure curve obtained from experiments at different frequencies of the fan.

[0025] For the static pressure measurement method, most are obtained according to the fan characteristic curve, that is, the static pressure value is obtained through a pressure sensor, and the corresponding air volume can be obtained by looking up according to the fan characteristic curve. Therefore, when measuring the air volume based on the static pressure method, it is necessary to pre-obtain the fan characteristic curve of the corresponding centrifugal fan.

[0026] In the fan air volume-static pressure curve, the abscissa represents the air volume, the ordinate represents the static pressure, and each curve represents the relationship between the static pressure and the air volume at each fan frequency. The curve can be obtained directly from the manufacturer or by using the method of controlling variables during the experiment. By adjusting the fan speed or the opening of the outlet valve, the operating conditions of the fan are changed, and the air volume and static pressure values under different conditions are measured. The air volume can be obtained by methods such as the anemometer method or the pitot tube method. That is, to obtain the relationship between the static pressure and the air volume when the fan frequency is 20 Hz, it is necessary to ensure that other parameters remain unchanged, change the air volume, and obtain the static pressure value according to the sensor. By continuously changing the fan speed or the opening of the outlet valve to change the air volume, different static pressure values can be obtained, and thus the characteristic curve of the static pressure and the air volume when the fan frequency is 20 Hz can be obtained.

[0027] 2. Obtain the air volume measurement deviation values measured by the static pressure method in the experiment under different wear degrees of the belt.

[0028] The drive type of the centrifugal fan is belt drive. The motor rotates and transmits energy to the fan impeller through the belt to drive the fan to rotate. Long-term use of the fan will inevitably cause local wear of the belt, resulting in slippage. After slippage, the energy transmitted from the motor driving wheel to the fan impeller will be reduced, that is, under the same frequency, the speed obtained by the fan impeller becomes smaller, the output air volume becomes smaller, and the energy loss increases.

[0029] Therefore, a belt tension measuring instrument needs to be installed under the belt or at the pulley to monitor the change of the belt tension in real time and judge the wear condition of the belt according to the change of the tension. When the belt wears, its tension will decrease accordingly. By monitoring the change of the tension, the wear degree of the belt can be detected in time.

[0030] Repeat the experiment according to the above method to analyze the influence degree of different belt wear degrees on the reliability of static pressure measurement. Among them, the wear degree of the belt can be imitated by adjusting the tightness of the belt. Under the same wear degree, the fan speed or the opening of the outlet valve is changed multiple times to change the air volume of the fan. The difference between the air volume value measured by the static pressure method and the air volume value obtained by the anemometer method or other methods (in this embodiment, the absolute value of the difference is calculated as the difference) is recorded as the air volume measurement deviation value. Using this method, the air volume measurement deviation values measured by the static pressure method under different belt wear degrees at the same fan frequency can be obtained.

[0031] 3. Analyze the differences between all the belt tension data obtained from the real-time monitoring data and the experimental monitoring data, and select multiple experimental monitoring data with similar belt conditions to the real-time monitoring data at different fan frequencies to calculate the deviation degree of the air volume values measured by the static pressure method based on the real-time monitoring data at different frequencies.

[0032] In the above step 2, different wear degrees of the belt were simulated by experimental methods, and the air volume measurement deviation values corresponding to each wear degree of the belt were obtained.

[0033] Since the wear degree is a continuous index and it is impossible to conduct experimental analysis on all wear degrees one by one, in this application, the similarity of the belt wear degree between the real-time monitoring data and the experimental monitoring data is based on the similarity of the tension data collected.

[0034] Furthermore, considering the rotation of the belt, the data instantaneously collected by the belt tension measuring instrument may not be able to well reflect the wear degree of the belt. Therefore, in order to obtain more accurate measurement results in this application, the belt tension data at t consecutive monitoring moments at each monitoring position are obtained for analysis. Then, the calculation method for the similarity of the belt wear degree between the real-time monitoring data and the experimental monitoring data of the fan at different frequencies is as follows: In the formula, represents the similarity of the belt wear degree between the real-time monitoring data a and the experimental monitoring data b when the frequency of the centrifugal fan is p. norm represents the normalization function, m represents the number of belt tension measuring instruments placed on the conveyor belt, t represents the length of the monitoring moment of each monitoring data, represents the belt tension data obtained by the real-time monitoring data a at the j-th monitoring moment of the i-th belt tension measuring instrument, represents the belt tension data obtained by the experimental monitoring data b at the j-th monitoring moment of the i-th belt tension measuring instrument. It should be understood that when the belt tension data obtained at the corresponding monitoring moments of each belt tension measuring instrument of the real-time monitoring data a and the experimental monitoring data b are similar, it indicates that the similarity of the belt wear degree between the real-time monitoring data a and the experimental monitoring data b is higher.

[0035] In the case where the motor frequency in the real-time monitoring data is p, the similarity of the belt wear degree is calculated by respectively comparing the real-time obtained real-time monitoring data a with each experimental monitoring data. , and a similarity threshold H = 0.9 is preset. The experimental monitoring data with similarity greater than the similarity threshold is recorded as the experimental monitoring data with similar belt conditions.

[0036] Through threshold screening, some experimental monitoring data with similar belt conditions to the real-time monitoring data a at the fan frequency p can be screened out. Suppose there are k times of experimental monitoring data with similar belt conditions, and the air volume measurement deviation values corresponding to these data are obtained. The normalized value of the average of the air volume measurement deviation values corresponding to these k times of experimental monitoring data is recorded as the deviation degree PL of the air volume value measured by the real-time monitoring data based on the static pressure method at the fan frequency p.

[0037] 4. And obtain the real-time monitoring data, which is the air volume value in the air volume-static pressure curve corresponding to the static pressure value measured by the static pressure method at the corresponding frequency.

[0038] Substitute the static pressure value measured by the static pressure method in the real-time monitoring data into the air volume-static pressure curve of the fan at the corresponding fan frequency to obtain the air volume value Fc measured in real time by the static pressure method.

[0039] Step : Measure the air volume in real time based on the wind speed method.

[0040] When using the wind speed method to measure the air volume, the main influencing factors of the measurement result are the instability and non-uniformity of the cross-sectional wind speed. Therefore, in this application, the wind speed uniformity and stability during the measurement by the wind speed method are obtained by analyzing the real-time monitoring data, and the reliability of the measurement result is obtained.

[0041] 1. Determine the wind speed stability based on the fluctuation degree of the wind speed data in all wind speed sensors.

[0042] In this embodiment, calculate the variance value of all wind speed data of each wind speed sensor within the acquisition time period, take the reciprocal of the mean value of the variance values calculated by all wind speed sensors and perform normalization to obtain the wind speed stability.

[0043] First, obtain the wind speed data F of the same wind speed sensor within a time period of length t. The wind speed data obtained by the first wind speed sensor is F1, F1 = {V11, V12,..., V1t}, where V11, V12, V1t respectively represent the wind speed data collected by the first wind speed sensor at the first moment, the second moment, and the t-th moment. Calculate the variance value of all wind speed data obtained by the same wind speed sensor within the acquisition time period. That is, if the variance of the obtained wind speed data is smaller, it indicates that the wind speed stability at the corresponding point of the wind speed sensor is stronger.

[0044] Then, for the n wind speed sensors on the cross-section set at the fan outlet, calculate the variance value of all wind speed data within the corresponding time period of length t respectively to obtain n variance values. Take the average value of the corresponding n wind speed variance values to obtain the variance average value, and take its reciprocal and perform normalization to obtain the wind speed stability. In this example, t = 20.

[0045] 2. Determine the distribution uniformity by using the chaotic distribution situation of the fluctuation degree calculated by all wind speed sensors and the average distribution situation of the fluctuation degree calculated at all acquisition moments.

[0046] In this embodiment, the variance of the variance values calculated by all wind speed sensors is used as the first wind speed uniformity index; the reciprocals of the wind speed variances of all wind speed sensors at each acquisition moment are normalized to obtain the wind speed uniformity at that moment, and the average value of the wind speed uniformities at all moments is used as the second wind speed uniformity index; the average value of the first and second wind speed uniformity indexes is used as the distribution uniformity.

[0047] Specifically, the variance of the variance values of n wind speed sensors is calculated as the first wind speed uniformity index. That is, the greater the difference in wind speed changes between the wind speeds at different positions, the worse the wind speed uniformity obtained at each position of the cross-section.

[0048] Based on the wind speed data collected by all sensors obtained at each moment within a time period of length t, the wind speed variance of the wind speeds collected by all sensors obtained at the same moment is calculated. That is, the greater the obtained wind speed variance, the more uneven the wind speed at the outlet of the centrifugal fan at that moment. After taking the reciprocal of the wind speed variance and normalizing it, it is denoted as the wind speed uniformity at the outlet of the centrifugal fan at that moment, and the average value of the wind speed uniformities at the outlets of the centrifugal fan obtained at t moments is denoted as the second wind speed uniformity index.

[0049] Then, according to the average value of the first wind speed uniformity index and the second wind speed uniformity index obtained above, the distribution uniformity of the wind speed at the fan outlet collected and obtained at the current moment is obtained.

[0050] 3. Positively fuse the wind speed stability index and the distribution uniformity to obtain the reliability of real-time measurement of air volume based on the wind speed method.

[0051] Based on the wind speed stability index and the distribution uniformity index obtained at the t moments adjacent to the target moment, the reliability Kf of measuring the air volume by the wind speed method is obtained. That is, the more stable the wind speed at the outlet of the centrifugal fan to be obtained, and the more uniform the wind speed distribution corresponding to different positions, that is, the greater the reliability Kf of measuring the air volume by the wind speed method to be obtained, the more accurate and reliable the air volume obtained based on the wind speed method. In this embodiment, the wind speed stability index and the distribution uniformity index are multiplied to obtain the reliability Kf of measuring the air volume by the wind speed method.

[0052] 4. Use the average wind speed at the current moment and the cross-sectional area corresponding to the measurement position of the wind speed sensor to determine the outlet air volume measured in real time based on the wind speed method.

[0053] Specifically, the average value of the wind speed values of all wind speed sensors collected at the current moment is multiplied by the cross-sectional area corresponding to the measurement position of the wind speed sensor to obtain the outlet air volume measured in real time based on the wind speed method.

[0054] Obtain the average value of the wind speed values obtained by each wind speed sensor at the monitoring moment, and multiply it by the cross-sectional area S of the air outlet to obtain the air volume Fv of the air outlet measured in real time based on the wind speed method.

[0055] Step : Comprehensive measurement of the air volume of a centrifugal ventilator.

[0056] According to the above information, this application obtains the measurement results of the centrifugal ventilator based on the wind speed method and the static pressure method respectively. Considering their respective influencing factors, the measurement results of the centrifugal ventilator can be more accurate by combining the two methods. The specific method is as follows: In the formula, Pw represents the final air volume of the centrifugal ventilator obtained by combining the static pressure method and the wind speed method, PL represents the deviation degree of the air volume value measured by the static pressure method based on the real-time monitoring data, Kf represents the reliability of measuring the air volume based on the wind speed method, Fc represents the air volume value measured in real time based on the static pressure method, and Fv represents the air volume of the air outlet measured in real time based on the wind speed method.

[0057] It should be understood that the greater the deviation degree of the air volume value measured by the static pressure method, and the more reliable the reliability of measuring the air volume based on the wind speed method, the more the measurement result can be obtained according to the wind speed method in the real-time monitoring result. On the contrary, the smaller the deviation degree of the air volume value measured by the static pressure method, and the less reliable the reliability of measuring the air volume based on the wind speed method, the more the measurement result can be obtained according to the static pressure method in the real-time monitoring result.

[0058] So far, through the method in this application, the air volume values measured in real time by the static pressure method and the wind speed method, as well as the deviation degree and reliability of their respective measurement methods, can be combined to determine the final air volume of the centrifugal ventilator.

[0059] Based on the same inventive concept as the above-mentioned air volume monitoring method of the centrifugal ventilator, another embodiment of this application also provides an air volume monitoring system for a centrifugal ventilator, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the air volume monitoring method of a centrifugal ventilator described in any one of the above.

[0060] Those skilled in the art will easily think of other implementation schemes of this application after considering the specification and practicing the invention here. This application aims to cover any variations, uses, or adaptive changes of this application. These variations, uses, or adaptive changes follow the general principles of this application and include common general knowledge or conventional technical means in the technical field not invented by this application.

[0061] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for monitoring the air volume of a centrifugal ventilator, characterized in that, The method includes the following steps: Obtain the air volume-static pressure curve obtained from experiments on the fan at different frequencies; obtain the air volume measurement deviation values measured by the static pressure method obtained from experiments on the belt under different wear degrees; analyze the differences between the real-time monitoring data and all the belt tension data obtained from the experimental monitoring data, and screen out multiple experimental monitoring data with belt conditions similar to the real-time monitoring data at different frequencies of the fan, so as to calculate the deviation degree of the air volume value measured by the static pressure method based on the real-time monitoring data at different frequencies; and obtain the air volume value in the air volume-static pressure curve corresponding to the static pressure value measured by the static pressure method based on the real-time monitoring data at the corresponding frequency. Determine the wind speed stability based on the fluctuation degree of the wind speed data in all the wind speed sensors; determine the distribution uniformity by using the chaotic distribution of the fluctuation degree calculated by all the wind speed sensors and the average distribution of the fluctuation degree calculated at all the acquisition moments; positively fuse the wind speed stability index and the distribution uniformity to obtain the reliability of the real-time air volume measurement based on the wind speed method; use the average wind speed at the current moment and the cross-sectional area corresponding to the measurement position of the wind speed sensor to determine the air volume at the air outlet measured in real time based on the wind speed method. Based on the air volume values measured in real time by the static pressure method and the wind speed method, as well as the deviation degrees and reliabilities of their respective measurement methods, determine the final air volume of the centrifugal fan.

2. The air volume monitoring method of a centrifugal ventilator according to claim 1, characterized in that The method for screening out multiple experimental monitoring data with belt conditions similar to the real-time monitoring data at different frequencies of the fan is as follows: Based on the differences between the real-time monitoring data and all the belt tension data obtained from any one of the experimental monitoring data at the same fan frequency, determine the similarity of the belt wear degree between the real-time monitoring data and the any one of the experimental monitoring data. Take the experimental monitoring data with the belt wear degree similarity greater than the preset similarity threshold as the experimental monitoring data with belt conditions similar to the real-time monitoring data.

3. The air volume monitoring method of a centrifugal ventilator according to claim 2, characterized in that, The method for determining the similarity of the belt wear degree is as follows: Calculate the normalized value of the cumulative sum value of the differences between the real-time monitoring data and all the belt tension data obtained from any one of the experimental monitoring data at the same fan frequency. Take the difference result between the value 1 and the normalized value as the similarity of the belt wear degree between the real-time monitoring data and the any one of the experimental monitoring data at the same fan frequency.

4. The air volume monitoring method of a centrifugal ventilator according to claim 2, characterized in that, The calculation method of the deviation degree is as follows: Take the normalized value of the average value of the air volume measurement deviation values corresponding to all the experimental monitoring data with belt conditions similar to the real-time monitoring data at the same frequency as the deviation degree of the air volume value measured by the static pressure method based on the real-time monitoring data at the same frequency.

5. The air volume monitoring method of a centrifugal ventilator according to claim 1, characterized in that, The method for determining the wind speed stability is: calculate the variance value of all the wind speed data of each wind speed sensor within the acquisition time period, take the reciprocal of the average value of the variance values calculated by all the wind speed sensors and then normalize it to obtain the wind speed stability.

6. The air volume monitoring method of a centrifugal ventilator according to claim 5, characterized in that, The method for determining the distribution uniformity is as follows: Take the variance of the variance values calculated by all the wind speed sensors as the first wind speed uniformity index. Take the reciprocal of the wind speed variance of all wind speed sensors at each acquisition moment and then normalize it as the wind speed uniformity at that moment, and take the average value of the wind speed uniformity at all moments as the second wind speed uniformity index; Take the average value of the first and second wind speed uniformity indexes as the distribution uniformity.

7. The air volume monitoring method of a centrifugal ventilator according to claim 1, characterized in that, The reliability is positively correlated with the wind speed stability and the distribution uniformity respectively.

8. The air volume monitoring method of a centrifugal fan according to claim 1, characterized in that, The method for determining the air volume at the air outlet measured in real time based on the wind speed method is as follows: Multiply the mean value of the wind speed values of all wind speed sensors collected at the current moment by the cross-sectional area corresponding to the measurement position of the wind speed sensor to obtain the air volume at the air outlet measured in real time based on the wind speed method.

9. The air volume monitoring method of a centrifugal ventilator according to claim 1, characterized in that, The method for determining the air volume of the final centrifugal ventilator is as follows: In the formula, Pw represents the air volume of the final centrifugal ventilator obtained by the comprehensive static pressure method and the wind speed method, PL represents the deviation degree of the air volume value measured by the static pressure method based on the real-time monitoring data, Kf represents the reliability of measuring the air volume based on the wind speed method, Fc represents the air volume value measured in real time based on the static pressure method, and Fv represents the air volume at the air outlet measured in real time based on the wind speed method.

10. An air volume monitoring system for a centrifugal ventilator, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements a method for monitoring the air volume of a centrifugal ventilator according to any one of claims 1-9.

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