A centrifugal fan performance degradation assessment method and system based on operating parameters

Abstract

A centrifugal fan performance degradation assessment method and system based on operating parameters, comprising the following steps: Step 1, obtaining the operating data of the centrifugal fan for T consecutive days during the initial period of use as performance benchmark data; Step 2, obtaining the recent operating data of the centrifugal fan for T consecutive days of a pair of related parameters selected in step 1 as performance evaluation data; Step 3, calculating the two-dimensional discrete distribution matrix of the performance benchmark data set and the performance evaluation data set; Step 4, weighting the overlapping values ​​of each matrix interval to obtain a performance evaluation score; Step 5, judging whether the performance of the centrifugal fan has degraded according to the performance evaluation score. The present invention is based on the fact that the fan operating parameters are mainly performance parameters, and uses two-dimensional discrete distribution overlap analysis to calculate the performance score. The principle is clear and the performance score result is interpretable. It makes up for the problem of the lack of performance degradation analysis methods for centrifugal fans at present, and solves the technical difficulties of fan performance degradation analysis.

Description

Technical Field

[0001] The present invention belongs to the field of centrifugal fan performance degradation analysis, and in particular relates to a centrifugal fan performance degradation evaluation method and system based on operating parameters. Background Art

[0002] Centrifugal fans are widely used in the industrial field as production equipment. They are used in various fields, such as ventilation, dust removal, ventilation and induced draft of boilers and industrial furnaces in mines, tunnels, cooling towers, vehicles, ships and buildings. Cement companies often use ventilation equipment, the most common ones are: grate cooler cooling fans, high-temperature fans, kiln head and kiln tail exhaust fans, etc., all of which are centrifugal fans. At present, under the wave of industrial Internet, centrifugal fan status monitoring has become more common. For example, large fans in power plants and key fans in cement plants have achieved common temperature monitoring, and some even have additional vibration sensors installed to monitor the operating status. The focus of these methods is to monitor the electrical and mechanical faults of the fan, such as coupling misalignment, bearing damage, wear, etc., while the monitoring and analysis of the fan's operating performance is not common at present. Wu Denghao et al. proposed in their patent "A pump and fan performance prediction method based on uncertainty analysis" (patent number CN201910930803) to obtain flow-pressure difference and flow-power performance curves, and use segmented prediction combined with uncertainty analysis to select the best prediction model to achieve accurate prediction of flow, and did not involve the evaluation of fan performance degradation. Centrifugal fan performance degradation is an inevitable problem that occurs during the long-term operation of the fan. The main reason is that the performance is degraded due to factors such as wear and heat generated during the operation of mechanical parts. Performance degradation is extremely harmful to the normal use of the fan. If the fan performance degrades to a certain extent and cannot reach the optimal level, it will cause a series of problems until the normal operation of production is affected. Due to the large number of performance parameters of centrifugal fans, how to evaluate the performance degradation of fans is a major difficulty. Summary of the invention

[0003] The object of the present invention is to provide a centrifugal fan performance degradation assessment method and system based on operating parameters to solve the above-mentioned problems.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A centrifugal fan performance degradation assessment method based on operating parameters comprises the following steps:

[0006] Step 1: Based on the main performance parameters of the centrifugal fan, a fan characteristic curve consisting of a pair of related parameters is selected, and the operation data of the centrifugal fan for T consecutive days during the initial use period is obtained as the performance benchmark data;

[0007] Step 2, obtaining the recent operation data of the centrifugal fan for the same consecutive T days of a pair of related parameters selected in step 1 as performance evaluation data;

[0008] Step 3, calculating the two-dimensional discrete distribution matrix of the performance benchmark data set and the performance evaluation data set;

[0009] Step 4, calculating the overlap value of the two-dimensional discrete distribution matrix of the performance evaluation data set and the two-dimensional discrete distribution matrix of the performance benchmark data set, and weighting the overlap value of each matrix interval to obtain a performance evaluation score;

[0010] Step 5: Determine whether the performance of the centrifugal fan has degraded based on the performance evaluation score.

[0011] Furthermore, in step 1 and step 2, the main performance parameters include the following parameter types: speed-R, air volume-L, wind pressure-H, power-N and efficiency η; the performance score corresponding to the default benchmark data is full marks, and the performance benchmark data dataset1 is recorded as [x, y], where x and y are a pair of selected associated parameters, and dataset1 is the performance benchmark data set; the performance evaluation data dataset2 is recorded as [x, y], where x and y are a pair of selected associated parameters, and dataset2 is the performance evaluation data set.

[0012] Furthermore, in step 1, the combination of associated parameters includes the following groups: air volume L-rotation speed R, air volume L-wind pressure H, air volume L-power N, air volume L-efficiency η, rotation speed R-wind pressure H; the obtained performance benchmark data requires that the continuous time meets the following conditions: 7≤T≤31.

[0013] Furthermore, the specific calculation steps of the two-dimensional discrete distribution matrix stats are as follows:

[0014] 1) First, the two parameters x and y in the data set are divided into equal intervals to obtain a two-dimensional matrix matrix. The matrix matrix is ​​a square matrix with K rows and K columns, and K is the number of division intervals; the discrete interval is determined by dividing the upper and lower limits of the corresponding parameters by the K value, where the upper and lower limits are determined by the actual measurable range of the centrifugal fan performance parameters; the value range of the number of division intervals K is: 50≤K≤100;

[0015] 2) Calculate the number of data points of the two-dimensional data set x, y in each square interval of the two-dimensional matrix, and obtain the two-dimensional quantity matrix matrix_num. The matrix_num matrix is ​​a square matrix with K rows and K columns.

[0016] 3) Select x or y as the parameter for calculating the distribution ratio, and calculate the distribution ratio stats of each interval of the matrix, where K is the number of divided intervals.

[0017] Furthermore, if the x parameter is selected as the main parameter for distribution calculation, the distribution ratio is calculated as follows:

[0018]

[0019] If the y parameter is selected as the main parameter for distribution calculation, the distribution ratio is calculated as follows:

[0020]

[0021] Furthermore, the specific calculation steps of the performance evaluation score are as follows:

[0022] Calculate the overlap value of each interval of the two-dimensional discrete distribution matrix stats2 of the performance evaluation data set and the two-dimensional discrete distribution matrix stats1 of the performance benchmark data set. The overlap value is the minimum value of the two distributions in the corresponding interval:

[0023] overlap ij =min(stats1 ij , stats2 ij )i=0, 1, ..., K-1; j=0, 1, ..., K-1

[0024] Calculate the weighted result of all overlap values ​​as the performance evaluation score PI:

[0025] If the x parameter is selected as the main parameter for distribution calculation in step 3, the performance evaluation score PI is calculated as follows:

[0026]

[0027] If the y parameter is selected as the main parameter for distribution calculation in step 3, the performance evaluation score PI is calculated as follows:

[0028]

[0029] Among them, matrix_num1 is the data volume matrix of each interval after the performance benchmark data set is divided into a two-dimensional matrix. The value range of the performance score PI is [0-1]. The closer the performance score is to 1, the better the performance of the centrifugal fan is, and it is close to the initial commissioning stage; the closer the performance score is to 0, the worse the performance of the centrifugal fan is, and there is a large deviation compared with the initial commissioning stage.

[0030] Further, step five: judging whether the performance of the centrifugal fan is degraded. The specific method is as follows: regularly obtain the performance evaluation data set at a certain time interval, calculate the fan performance score PI according to the steps described in steps 2, 3, and 4, and thereby obtain the trend data set PI_trend_arr of the fan performance score over time and date, and comprehensively judge whether the fan performance is degraded by the following two conditions;

[0031] Condition 1: The most recent fan performance score is less than the previous fan performance score;

[0032] Condition 2: The fan performance score trend data shows a downward trend over time;

[0033] If condition 1 or condition 2 is met, it is determined that the fan performance has been degraded. Otherwise, if neither condition 1 nor condition 2 is met, it is determined that the fan performance has not been degraded.

[0034] Furthermore, the method for judging the downward trend in condition 2 is as follows: calculate the Pearson-Pearson correlation coefficient c between the fan performance score trend data PI_trend_arr and the corresponding timestamp sequence. If c is less than -0.65, the fan performance score has a downward trend over time. Otherwise, there is no downward trend.

[0035] Furthermore, the centrifugal fan performance degradation assessment system based on operating parameters includes

[0036] A performance benchmark data acquisition module is used to select a fan characteristic curve composed of a pair of associated parameters based on the main performance parameters of the centrifugal fan, and obtain T consecutive days of operation data of the centrifugal fan during the initial period of use as performance benchmark data;

[0037] A performance evaluation data acquisition module is used to acquire the recent operation data of a pair of related parameters selected by the centrifugal fan in step 1 for the same consecutive T days as performance evaluation data;

[0038] A two-dimensional discrete distribution matrix calculation module is used to calculate the two-dimensional discrete distribution matrix of the performance benchmark data set and the performance evaluation data set;

[0039] An evaluation score module is used to calculate the overlap value of the two-dimensional discrete distribution matrix of the performance evaluation data set and the two-dimensional discrete distribution matrix of the performance benchmark data set, and weight the overlap value of each matrix interval to obtain a performance evaluation score;

[0040] The judgment module is used to judge whether the performance of the centrifugal fan is degraded according to the performance evaluation score.

[0041] Compared with the prior art, the present invention has the following technical effects:

[0042] The present invention starts from the main performance parameters of the centrifugal fan, selects a fan characteristic curve formed by a pair of related parameters, obtains a data set formed by the curve in the initial operation of the centrifugal fan and a data set in the recent operation to form a performance benchmark data set and a performance evaluation data set, calculates the distribution matrix after discrete division of the two data sets, obtains the performance score by calculating the overlap of the distribution matrix and weighted summing it, and finally judges whether the fan performance is degraded according to whether the performance score of the fan decreases with the running time or shows a downward trend over time.

[0043] The present invention realizes the performance degradation evaluation of centrifugal fans based on operating parameters. Starting from the main performance parameters of the centrifugal fan, the present invention selects a fan characteristic curve formed by a pair of associated parameters, obtains the performance benchmark data set formed by the curve in the initial operation and the performance evaluation data set formed in the recent operation, calculates the distribution matrix after discrete division of the two data sets, calculates the overlap of the distribution matrix and weightedly calculates the performance score, and finally judges whether the fan performance is degraded according to whether the centrifugal fan performance score decreases or shows a downward trend with the running time. Based on the fact that the fan operating parameters are mainly performance parameters, the present invention uses two-dimensional discrete distribution overlap analysis to calculate the performance score, the principle is clear and the performance score result is interpretable. It makes up for the problem of the lack of the current centrifugal fan performance degradation analysis method, and solves the technical difficulties of the fan performance degradation analysis. The present invention uses the centrifugal fan operation mechanism to achieve the goal of quantitatively evaluating the degree of centrifugal fan performance degradation, which can provide an operation and maintenance basis for ensuring the efficient operation of the centrifugal fan, reduce the continuous production loss caused by the performance degradation of the centrifugal fan, and provide guidance and suggestions for avoiding serious performance degradation of the fan performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Overall flow chart of a centrifugal fan performance degradation assessment method based on operating parameters

[0045] Figure 2 Comparison of performance degradation data of high temperature fans in a cement plant

[0046] Figure 3 Typical trend chart of centrifugal fan performance score

[0047] Figure 4 Schematic diagram of the partitioning process. DETAILED DESCRIPTION

[0048] The present invention proposes a centrifugal fan performance degradation evaluation method based on operating parameters to make up for the lack of centrifugal fan performance degradation analysis and evaluation methods and technologies, solve the difficult problems existing in centrifugal fan performance degradation analysis, and provide operation and maintenance decisions to ensure efficient operation of the fan.

[0049] Starting from the main performance parameters of the centrifugal fan, this method selects a fan characteristic curve formed by a pair of related parameters, obtains the data set formed by the initial operation of the centrifugal fan and the data set in the recent operation to form a performance benchmark data set and a performance evaluation data set, and calculates the distribution matrix after discrete division of the two data sets. The performance score is obtained by calculating the overlap of the distribution matrix and weighted summing it up. Finally, whether the fan performance is degraded is judged according to whether the performance score of the fan decreases with the running time or shows a downward trend over time.

[0050] To achieve the above object, the technical solution adopted by the present invention is: a centrifugal fan performance degradation assessment method based on operating parameters, comprising the following steps:

[0051] Step 1: Based on the main performance parameters of the centrifugal fan, including the following parameter types: speed-R, air volume-L, air pressure-H, power-N and efficiency η, select a pair of associated parameters to form a fan characteristic curve (also called a fan performance curve), and obtain the operating data of the centrifugal fan for T consecutive days during the initial period of use as the performance benchmark data (the performance score corresponding to the default benchmark data is full score) dataset1 = [x, y], where x and y are a pair of selected associated parameters, and dataset1 is the performance benchmark data set.

[0052] The above-mentioned combination of related parameters includes the following groups: air volume L-rotation speed R, air volume L-wind pressure H, air volume L-power N, air volume L-efficiency η, rotation speed R-wind pressure H. The obtained performance benchmark data requires the continuous time to meet the following conditions: 7≤T≤31.

[0053] Step 2: Obtain the recent T-day operation data of the centrifugal fan for a pair of related parameters selected in step 1 as performance evaluation data dataset2 = [x, y], where x and y are a pair of related parameters selected, and dataset2 is the performance evaluation data set.

[0054] Step 3: Calculate the two-dimensional discrete distribution matrices stats1 and stats2 of the performance benchmark dataset dataset1 and the performance evaluation dataset dataset2.

[0055] The specific calculation steps of the two-dimensional discrete distribution matrix stats are as follows:

[0056] First, the two parameters x and y in the data set are divided into equal intervals to discretize and obtain a two-dimensional matrix matrix. The matrix matrix is ​​a square matrix with K rows and K columns. K is the number of division intervals.

[0057] The discrete interval is determined by dividing the upper and lower limits of the corresponding parameters by the K value, where the upper and lower limits are determined by the actual measurable range of the centrifugal fan performance parameters; the value range of the number of divided intervals K is: 50≤K≤100.

[0058] 2) Calculate the number of data points of the two-dimensional data set x, y in each square interval of the two-dimensional matrix, and obtain the two-dimensional quantity matrix matrix_num. The matrix_num matrix is ​​a square matrix with K rows and K columns.

[0059] 3) Select x or y as the main parameter for calculating the distribution ratio, and calculate the distribution ratio stats of each interval of the matrix. K is the number of partition intervals.

[0060] If the x parameter is selected as the main parameter for distribution calculation, the distribution ratio is calculated as follows:

[0061]

[0062] If the y parameter is selected as the main parameter for distribution calculation, the distribution ratio is calculated as follows:

[0063]

[0064] Step 4: Calculate the overlap value between the two-dimensional discrete distribution matrix stats2 of the performance evaluation data set and the two-dimensional discrete distribution matrix stats1 of the performance benchmark data set, and weight the overlap value of each matrix interval to obtain the performance evaluation score.

[0065] The specific steps for calculating the performance evaluation score are as follows:

[0066] Calculate the overlap value for each interval, which is the minimum value of the two distributions in the corresponding interval:

[0067] overlap ij =min(stats1 ij , stats2 ij )i=0, 1, ..., K-1; j=0, 1, ..., K-1

[0068] Calculate the weighted result of all overlap values ​​as the performance evaluation score PI:

[0069] If the x parameter is selected as the main parameter for distribution calculation in step 3, the performance evaluation score PI is calculated as follows:

[0070]

[0071] If the y parameter is selected as the main parameter for distribution calculation in step 3, the performance evaluation score PI is calculated as follows:

[0072]

[0073] Among them, matrix_num1 is the data volume matrix of each interval after the performance benchmark data set is divided into a two-dimensional matrix. The value range of the performance score PI is [0-1]. The closer the performance score is to 1, the better the performance of the centrifugal fan is, and it is close to the initial commissioning stage (the performance is full score); the closer the performance score is to 0, the worse the performance of the centrifugal fan is, and there is a large deviation compared with the initial commissioning stage.

[0074] Step 5: Determine whether the centrifugal fan performance has degraded.

[0075] The specific method is as follows: regularly obtain performance evaluation data sets at certain time intervals, calculate the fan performance score PI according to the steps described in steps 2, 3, and 4, and thereby obtain the trend data set PI_trend_arr of the fan performance score over time and date. The following two conditions can be used to comprehensively judge whether the fan performance has degraded.

[0076] Condition 1: The most recent fan performance score is less than the previous fan performance score.

[0077] Condition 2: The fan performance score trend data shows a downward trend over time.

[0078] The method for judging the downward trend in condition 2 is as follows: calculate the Pearson-Pearson correlation coefficient c between the fan performance score trend data PI_trend_arr and the corresponding timestamp sequence. If c is less than -0.65, the fan performance score has a downward trend at any time. Otherwise, there is no downward trend.

[0079] If condition 1) or condition 2) is met, it can be determined that the fan performance has been degraded. On the contrary, if both condition 1) and condition 2) are not met, it can be determined that the fan performance has not been degraded.

[0080] See attached Figure 1 . Figure 1 The present invention is an overall flow chart of a centrifugal fan performance degradation assessment method based on operating parameters. Starting from the main performance parameters of the centrifugal fan, the present invention first selects a pair of performance parameters to form a centrifugal fan characteristic curve, obtains a performance benchmark data set formed by the curve in the initial stage of operation and a performance assessment data set formed in the recent operation, divides the two data sets into equally spaced discrete parts, obtains the number of data points in each interval of the actual data set, and calculates the distribution matrix based on the number of points, and then calculates the overlapping value of the distribution matrix and weighted sums it to obtain the performance score, and finally judges whether the centrifugal fan performance is degraded based on whether the centrifugal fan performance score decreases or shows a downward trend with the running time.

[0081] See attached Figure 2 . Figure 2This is a comparison chart of the performance degradation data of a high-temperature fan in a cement plant. From the figure, it can be observed that there is an obvious data offset in the performance benchmark data set and the performance evaluation data set of the two major performance parameters of the high-temperature fan speed and wind pressure. That is, under the same speed conditions in the performance evaluation data set, the wind pressure is obviously lower than that in the performance benchmark data set. From the analysis of the operating mechanism, the high-temperature fan has already experienced relatively obvious performance degradation. Therefore, the two-dimensional distribution overlap of the performance parameters evaluated by the present invention can obtain an accurate conclusion on performance degradation.

[0082] See attached Figure 3 . Figure 3 The following is a typical trend chart of centrifugal fan performance scores. The performance score of the centrifugal fan increases with the operating time. Compared with the performance benchmark state at the beginning of operation, the actual performance of the centrifugal fan is in a trend of continuous degradation and decline. Therefore, based on the actual performance degradation of the centrifugal fan, an operation and maintenance plan can be accurately arranged, such as fan impeller dust cleaning, wear parts replacement and other measures to ensure that the fan performance is at a high level and avoid large production losses.

[0083] Figure 4 In the figure, i is the number after the x parameter is divided, j is the number after the y parameter is divided, i = 0, 1, ... K-1; j = 0, 1, ... K-1.

Claims

1. A centrifugal fan performance degradation assessment method based on operating parameters, characterized in that: The following steps are involved: Step 1: Based on the main performance parameters of the centrifugal fan, a fan characteristic curve consisting of a pair of related parameters is selected, and the operation data of the centrifugal fan for T consecutive days during the initial use period is obtained as the performance benchmark data; Step 2, obtaining the recent operation data of the centrifugal fan for the same consecutive T days of a pair of associated parameters selected in step 1 as performance evaluation data; Step 3, calculating the two-dimensional discrete distribution matrix of the performance benchmark data set and the performance evaluation data set; Step 4, calculating the overlap value of the two-dimensional discrete distribution matrix of the performance evaluation data set and the two-dimensional discrete distribution matrix of the performance benchmark data set, and weighting the overlap value of each matrix interval to obtain a performance evaluation score; Step 5, judging whether the performance of the centrifugal fan is degraded according to the performance evaluation score; The specific calculation steps for performance evaluation scores are as follows: Calculate the overlap value of each interval of the two-dimensional discrete distribution matrix stats2 of the performance evaluation data set and the two-dimensional discrete distribution matrix stats1 of the performance benchmark data set. The overlap value is the minimum value of the two distributions in the corresponding interval: overlap ij =min(stats1 ij ,states2 ij )i=0,1,…,K-1;j=0,1,…,K-1 Calculate the weighted result of all overlap values ​​as the performance evaluation score PI: If the x parameter is selected as the main parameter for distribution calculation in step 3, the performance evaluation score PI is calculated as follows: If the y parameter is selected as the main parameter for distribution calculation in step 3, the performance evaluation score PI is calculated as follows: Where matrix_num1 is the data volume matrix of each interval after the performance benchmark data set is divided into a two-dimensional matrix. The value range of the performance score PI is [0-1]. The closer the performance score is to 1, the better the performance of the centrifugal fan is, and it is close to the initial commissioning stage. The closer the performance score is to 0, the worse the centrifugal fan performance is, which is a large deviation compared to the initial commissioning stage.

2. A centrifugal fan performance degradation assessment method based on operating parameters according to claim 1, characterized in that: In step 1 and step 2, the main performance parameters include the following parameter types: speed-R, air volume-L, air pressure-H, power-N and efficiency η; the performance score corresponding to the default benchmark data is full score, and the performance benchmark data dataset1 is recorded as [x, y], where x and y are a pair of selected associated parameters, and dataset1 is the performance benchmark data set; the performance evaluation data dataset2 is recorded as [x, y], where x and y are a pair of selected associated parameters, and dataset2 is the performance evaluation data set.

3. The centrifugal fan performance degradation assessment method based on operating parameters according to claim 1, characterized in that: In step 1, the combination of associated parameters includes the following groups: air volume L-rotation speed R, air volume L-wind pressure H, air volume L-power N, air volume L-efficiency η, rotation speed R-wind pressure H; the obtained performance benchmark data requires the continuous time to meet the following conditions: 7≤T≤31.

4. The centrifugal fan performance degradation assessment method based on operating parameters according to claim 1, characterized in that: The specific calculation steps of the two-dimensional discrete distribution matrix stats are as follows: 1) First, the two parameters x and y in the data set are divided into equal intervals to obtain a two-dimensional matrix matrix. The matrix matrix is ​​a square matrix with K rows and K columns, where K is the number of division intervals; The discrete interval is determined by dividing the upper and lower limits of the corresponding parameters by the K value, where the upper and lower limits are determined by the actual measurable range of the centrifugal fan performance parameters; the value range of the number of divided intervals K is: 50≤K≤100; 2) Calculate the number of data points of the two-dimensional data set x, y in each square interval of the two-dimensional matrix, and obtain the two-dimensional quantity matrix matrix_num. The matrix_num matrix is ​​a square matrix with K rows and K columns; 3) Select x or y as the parameter for calculating the distribution ratio, and calculate the distribution ratio stats of each interval of the matrix ij , K is the number of partition intervals.

5. A centrifugal fan performance degradation assessment method based on operating parameters according to claim 4, characterized in that: If the x parameter is selected as the main parameter for distribution calculation, the distribution ratio is calculated as follows: If the y parameter is selected as the main parameter for distribution calculation, the distribution ratio is calculated as follows:

6. The centrifugal fan performance degradation assessment method based on operating parameters according to claim 1, characterized in that: Step 5: Determine whether the performance of the centrifugal fan has degraded. The specific method is as follows: obtain the performance evaluation data set regularly at a certain time interval, calculate the fan performance score PI according to the steps described in steps 2, 3, and 4, and obtain the trend data set PI_trend_arr of the fan performance score over time and date, and comprehensively judge whether the fan performance has degraded based on the following two conditions; Condition 1: The most recent fan performance score is less than the previous fan performance score; Condition 2: The fan performance score trend data shows a downward trend over time; If condition 1 or condition 2 is met, it is determined that the fan performance has been degraded. Otherwise, if neither condition 1 nor condition 2 is met, it is determined that the fan performance has not been degraded.

7. A centrifugal fan performance degradation assessment method based on operating parameters according to claim 6, characterized in that: The method for judging the downward trend in condition 2 is as follows: calculate the Pearson-Pearson correlation coefficient c between the fan performance score trend data PI_trend_arr and the corresponding timestamp sequence. If c is less than -0.65, the fan performance score has a downward trend over time. Otherwise, there is no downward trend.

8. A centrifugal fan performance degradation assessment system based on operating parameters, which operates the centrifugal fan performance degradation assessment method based on operating parameters as claimed in any one of claims 1 to 7, characterized in that: include A performance benchmark data acquisition module is used to select a fan characteristic curve composed of a pair of associated parameters based on the main performance parameters of the centrifugal fan, and obtain T consecutive days of operation data of the centrifugal fan during the initial period of use as performance benchmark data; A performance evaluation data acquisition module is used to acquire the recent operation data of a pair of related parameters selected by the centrifugal fan in step 1 for the same consecutive T days as performance evaluation data; A two-dimensional discrete distribution matrix calculation module is used to calculate the two-dimensional discrete distribution matrix of the performance benchmark data set and the performance evaluation data set; An evaluation score module is used to calculate the overlap value of the two-dimensional discrete distribution matrix of the performance evaluation data set and the two-dimensional discrete distribution matrix of the performance benchmark data set, and weight the overlap value of each matrix interval to obtain a performance evaluation score; The judgment module is used to judge whether the performance of the centrifugal fan is degraded according to the performance evaluation score.

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