A method for fitting the performance curve of on-site water pumps

Abstract

The present invention relates to a method for fitting the performance curve of an on-site water pump, which comprises the following steps: S1: Establish the test performance curve of the water pump based on the test input parameters; S2: Obtain the current input parameters of the on-site water pump; S3: Calculate the spatial distance according to the current input parameters and the test input parameters, and combine the test performance curve of the water pump to fit the performance curve of the on-site water pump. The present invention combines the simulation experiment data to fit the performance curve closest to the test points, which is beneficial for the power plant to quickly and accurately fit the performance curve of the water pump during actual application, meet the on-site construction period requirements, facilitate tracking the change trend of the water pump performance on site, accurately reflect the performance of the on-site water pump, and avoid the operation safety risks caused by the curve change due to the structural change during the installation of some water pumps.

Description

Technical Field

[0001] The present invention relates to the technical field of water pump performance detection, and particularly to a method for fitting the performance curve of an on-site water pump. Background Art

[0002] A water pump is a fluid machine for transporting liquids or increasing the pressure of liquids, and is widely used in various sectors and fields of industry, agriculture and people's lives. The basic performance parameters of a water pump include flow rate, head, power, efficiency, rotational speed, etc. Usually, the curve representing the relationship and variation law between the main performance parameters of a water pump is called the performance curve of the water pump. Water pump manufacturers often provide the performance curve of the water pump when leaving the factory. However, in actual applications, it is also necessary to make certain adjustments to the performance curve of the water pump leaving the factory according to on-site conditions and structural changes caused by the actual installation of the water pump, etc.

[0003] Due to limited conditions, power plants can only conduct tests on individual operating points. In this case, if it is necessary to determine the actual performance curve of a water pump, the currently adopted technology is the measuring point translation method, that is, one or several operating points of the water pump are made, and the curve provided by the manufacturer is translated to the newly made operating point or their average position without any correction.

[0004] Since the existing technology is only the translation of the manufacturer's curve, it cannot solve the curve change caused by the structural change of the water pump due to installation. Therefore, the performance of the water pump during actual application cannot be correctly predicted, which will lead to a deviation between the fluid flow rate or pressure in the pipeline and the design value. The fluid in the pipeline cannot maintain a normal flow rate or pressure, which may lead to a decrease in the system operation efficiency and pose a potential safety hazard during operation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to fit the performance curve of an on-site water pump with curve changes caused by structural changes due to installation, and provide a method for fitting the performance curve of an on-site water pump to obtain the actual performance curve of the on-site water pump and more accurately reflect the performance of the water pump.

[0006] The technical solution adopted by the present invention to solve its technical problems is: constructing a method for fitting the performance curve of an on-site water pump, including the following steps:

[0007] S1: Establish a water pump test performance curve based on test input parameters;

[0008] S2: Obtain the current input parameters of the on-site water pump;

[0009] S3: Calculate the spatial distance according to the current input parameters and the test input parameters, and combine the water pump test performance curve to fit the performance curve of the on-site water pump.

[0010] In the on-site water pump performance curve fitting method of the present invention, step S1 includes:

[0011] S11: Establish a three-dimensional model of the water pump;

[0012] S12: Screen and set the test input parameters according to the performance influencing factors of the water pump;

[0013] S13: Perform three-dimensional simulation according to the test input parameters in combination with the three-dimensional model to obtain the test performance curve of the water pump.

[0014] In the on-site water pump performance curve fitting method of the present invention, step S13 includes:

[0015] S131: Judge whether the maximum deviation between the closest curves in the test performance curve of the water pump obtained by simulation is less than the threshold;

[0016] S122: If it is judged that the maximum deviation is not less than the threshold, readjust the test input parameters and perform simulation to obtain the adjusted test performance curve of the water pump;

[0017] S123: Repeat S121 - S122 until it is judged that the maximum deviation is less than the threshold, and then execute step S2.

[0018] Preferably, in the on-site water pump performance curve fitting method of the present invention, in step S12, the orthogonal test method is used to design the test input parameters.

[0019] In the on-site water pump performance curve fitting method of the present invention, step S3 includes:

[0020] S31: Calculate the spatial distance between the current input parameters and the test input parameters, and obtain two sets of data with the smallest and the second smallest spatial distances;

[0021] S32: Fit the on-site water pump performance curve according to the two sets of data with the smallest and the second smallest spatial distances and in combination with the corresponding test performance curves of the water pump.

[0022] Preferably, obtaining the two sets of data with the smallest and the second smallest spatial distances includes the smallest spatial distance, the test input parameters corresponding to the smallest spatial distance, the second smallest spatial distance, and the test input parameters corresponding to the second smallest spatial distance.

[0023] In the on-site water pump performance curve fitting method of the present invention, step S32 further includes:

[0024] The minimum space distance and the second minimum space distance calculate weights according to a proportional rule; the on-site pump performance curve is obtained by comparing the minimum space distance and the pump test performance curves corresponding to the second minimum space distance according to the weights.

[0025] Preferably, the calculation of weights according to the proportional rule satisfies the following formula:

[0026]

[0027] is the test performance curve of the second minimum space distance, is the test performance curve of the minimum space distance, (x1’, x2‘, …, x i ’), (x1“, x2”, …, x i “) are test input parameters, d1 is the minimum space distance, d2 is the second minimum space distance, Q is the flow rate of the pump, and P is the head of the pump.

[0028] In the on-site pump performance curve fitting method of the present invention, the following steps are further included:

[0029] Measure the on-site operating point of the on-site pump; calculate a correction parameter according to the on-site operating point, and the correction parameter corrects the on-site pump performance curve to obtain the final on-site pump performance curve.

[0030] Preferably, the calculation of the correction parameter according to the on-site operating point, and the correction parameter corrects the on-site pump performance curve to obtain the final on-site pump performance curve includes:

[0031] If there is only one on-site operating point, directly use the on-site operating point to correct the on-site pump performance curve;

[0032] If there are multiple on-site operating points, calculate the average operating point by the least squares method to obtain the correction parameter to correct the on-site pump performance curve.

[0033] Implementing the on-site pump performance curve fitting method of the present invention has the following beneficial effects:

[0034] Establish a pump test performance curve based on test input parameters; obtain the current input parameters of the on-site pump; calculate the space distance according to the current input parameters and the test input parameters, and combine the pump test performance curve to fit the on-site pump performance curve to obtain the actual on-site pump performance curve, which can more accurately reflect the performance of the on-site pump, is beneficial for the power plant to quickly and accurately fit the performance curve of the pump during actual application, is convenient for on-site tracking of the change trend of the pump performance, evaluates the usability of the pump, and avoids the operation safety risks caused by the curve change due to the structural change during the installation of some pumps. Brief Description of the Drawings

[0035] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0036] Figure 1 is a schematic flowchart of fitting the performance curve of the on-site water pump provided by the embodiment of the present invention;

[0037] Figure 2 is a schematic flowchart of establishing the test performance curve of the water pump provided by the embodiment of the present invention. Detailed Embodiments

[0038] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed embodiments of the present invention will now be described in detail with reference to the drawings.

[0039] Refer to Figure 1 , Figure 1 which is a schematic flowchart of fitting the performance curve of the on-site water pump provided by the embodiment of the present invention.

[0040] Specifically, as shown in Figure 1 , the method for fitting the performance curve of the on-site water pump includes:

[0041] Step S1: Establish a test performance curve of the water pump based on test input parameters;

[0042] Step S2: Obtain the current input parameters of the on-site water pump;

[0043] Step S3: Calculate the spatial distance according to the current input parameters and the test input parameters, and combine the test performance curve of the water pump to fit the performance curve of the on-site water pump.

[0044] Refer to Figure 2 , Figure 2 which is a schematic flowchart of establishing the test performance curve of the water pump provided by the embodiment of the present invention.

[0045] Furthermore, as shown in Figure 2 , in this embodiment, step S1 of establishing a test curve of the water pump based on test input parameters includes:

[0046] Step S11: Establish a three-dimensional model of the water pump;

[0047] Step S12: Screen and set the test input parameters according to the performance influencing factors of the water pump;

[0048] Step S13: Perform three-dimensional simulation according to the test input parameters in combination with the three-dimensional model to obtain the test performance curve of the water pump.

[0049] Specifically, in step S11, the three-dimensional model of the water pump is established by scanning the water pump with a three-dimensional imaging scanner. Among them, the three-dimensional imaging scanner is used to scan the shape and structure of the water pump to obtain the imaging of the water pump, and can convert the three-dimensional information of the water pump into digital signals that can be directly processed by a computer. The three-dimensional imaging scanner has the advantages of high data sampling rate, high resolution, high precision, etc. It can be understood that the three-dimensional model of the water pump can also be established by other methods.

[0050] In step S12, the test input parameters are screened and set according to the performance influencing factors of the water pump. Specifically, the performance influencing factors of the water pump can be the front seal ring clearance, the rear seal ring clearance, the axial clearance, the radial clearance, etc. The influencing factors that may cause greater structural changes during actual installation are selected from the performance influencing factors of the water pump as the test input parameters, and then the orthogonal test method is used to design the test parameters.

[0051] Among them, the orthogonal test method is a mathematical statistics method for arranging and analyzing multi-factor tests. It can test various influencing factors of the water pump performance, and different states of various factors in the test are called levels. Therefore, when using the orthogonal test method to design the test parameters, it is necessary to test each performance influencing factor and different levels of each factor. The advantage of using the orthogonal experiment method to design the test input parameters is that the number of required tests is small and it is convenient to use, so as to achieve good test results and high efficiency, which is beneficial to improving the accuracy of the simulation results of the water pump test performance curve.

[0052] In a specific embodiment of the present invention, four performance influencing factors of the water pump, namely the front seal ring clearance, the rear seal ring clearance, the axial clearance, and the radial clearance, are selected. The test input parameters are designed by the orthogonal test method, and the test input parameters shown in Table 1 below can be generated:

[0053] Table 1

[0054]

[0055] It can be seen from the above orthogonal table that there are four performance influencing factors of the test input parameters, and 9 groups of test input parameters (x1, x2, x3, x4) are generated after being designed by the orthogonal test method. Among them, x1 is the front seal ring clearance, x2 is the rear seal ring clearance, x3 is the axial clearance, x4 is the radial clearance, and each factor corresponds to the same three level values of 1mm, 0mm, and -1mm. The above orthogonal table is generated by testing the above four factors and three levels of each factor by the orthogonal test method, so that each level of each factor touches each level of another factor once. Each group of test input parameters (x1, x2, x3, x4) is combined with the three-dimensional model for simulation to obtain the water pump test performance curve corresponding to the test input parameters.

[0056] In step S13, according to the test input parameters and in combination with the 3D model, 3D simulation is carried out to obtain the pump test performance curve. Specifically, the 3D simulation is carried out by the professional pump software Pumplinx. The horizontal values of each group of test input parameters and the pump 3D model are respectively input into the pump software Pumplinx, and Pumplinx simulates the pump test performance curve according to the test input parameters and the 3D model. Among them, the software Pumplinx is a CFD (Computational Fluid Dynamics) software developed for the hydraulic simulation calculation of various pumps. It has a fully automatic Cartesian grid generator, which is convenient for directly generating spatial calculation grids from CAD files; it includes model processing, grid division, solution, and post-processing. Using the Pumplinx software to simulate the pump simulation performance curve can greatly shorten the time, with a fast calculation speed, achieving the technical effect of accurate simulation results of the performance curve. It can be understood that the performance curve of the pump can also be simulated by other simulation software.

[0057] In this embodiment, step S13 further includes the following steps:

[0058] Step S131: Judge whether the maximum deviation between the closest curves in the pump test performance curve obtained by simulation is less than the threshold value;

[0059] Step S132: If it is judged that the maximum deviation is not less than the threshold value, readjust the test input parameters and simulate to obtain the adjusted pump test performance curve;

[0060] Step S133: Repeat steps S131 - S132 until it is judged that the maximum deviation is less than the threshold value, and then execute step S2.

[0061] Specifically, in the embodiment of the present invention, after the pump software Pumplinx simulates multiple pump test performance curves according to the test input parameters and in combination with the 3D model, the deviation between each adjacent pump test performance curve is calculated, and it is judged whether the maximum deviation between the closest pump test performance curves is less than the threshold value. The usual deviation in engineering design is 5%, that is, the deviation within 5% is acceptable. However, the error of the result calculated by simulation is often higher than 5%, and there is no theory to ensure that it must be within a certain range. Therefore, preferably, the maximum deviation threshold is taken as 7%, indicating that the simulation error will not overwhelm the design error. It can be understood that the maximum deviation threshold can be 10% or other reasonable values.

[0062] If it is determined that the maximum deviation of the performance curve of the nearest pump test is not less than the threshold value, then readjust the level value of a certain test input parameter or add a level value, and simulate the pump software Pumplinx according to the adjusted test input parameters and the three-dimensional model to obtain the adjusted pump test performance curve. Repeat steps S131 - S132 until it is determined that the maximum deviation is less than 7%, and then continue to execute step S2.

[0063] In addition, it should be supplemented and explained that the test input parameters, the adjusted test input parameters, and a series of pump test performance curves corresponding to the test input parameters obtained by simulation in the above steps are all stored in the database.

[0064] In the embodiment of the present invention, the current input parameters in step S2 are measured by the acquisition equipment installed on site for the performance influencing factors of the pump after the on-site pump installation.

[0065] In the embodiment of the present invention, step S3 further includes the following steps:

[0066] Step S31: Calculate the spatial distance between the current input parameters and the test input parameters to obtain two sets of data with the smallest and the second smallest spatial distances;

[0067] Step S32: Fit the on-site pump performance curve according to the two sets of data with the smallest and the second smallest spatial distances and the corresponding pump test performance curves.

[0068] Specifically, in step S31, the definition of the spatial distance is as shown in formula (1), and the spatial distance is calculated according to formula (1), and the calculated spatial distance values are compared to obtain two sets of data with the smallest and the second smallest spatial distances.

[0069]

[0070] where the subscript i represents the type, is to the spatial distance of (x1, x2,..., x i ); is the current input parameter; (x1, x2,..., x i ) is the test input parameter.

[0071] Specifically, the two sets of data with the smallest and the second smallest spatial distances obtained in step S31 include the minimum spatial distance, the test input parameter corresponding to the minimum spatial distance; the second smallest spatial distance, and the test input parameter corresponding to the second smallest spatial distance.

[0072] In an embodiment of the present invention, step S32 further includes calculating weights for the minimum space distance and the second minimum space distance according to a proportional rule; comparing the pump test performance curves corresponding to the minimum space distance and the second minimum space distance according to the influence of the weights to obtain the on-site pump performance curve.

[0073] Specifically, the calculation of weights according to the proportional rule in step S32 satisfies formula (2) as follows:

[0074]

[0075] where f′(Q, P) is the on-site pump performance curve obtained after the influence of the weights; is the test performance curve of the second minimum space distance, is the test performance curve of the minimum space distance, (x1’, x2‘,…, x i ’) are the test input parameters corresponding to the minimum space distance, (x1“, x2”,…, x i “) are the test input parameters corresponding to the second minimum space distance, d1 is the minimum space distance, d2 is the second minimum space distance, Q is the flow rate of the pump, and P is the head of the pump.

[0076] In an embodiment of the present invention, in order to obtain a more accurate on-site pump performance curve, the following steps are further included: measuring the on-site operating point of the on-site pump; calculating a correction parameter according to the on-site operating point, and correcting the on-site pump performance curve with the correction parameter to obtain the final on-site pump performance curve.

[0077] Specifically, measure the on-site operating point of the on-site pump under the current input parameters of the on-site pump. At this time, the measured on-site operating point may be one or more, depending on the on-site conditions. If there is only one on-site operating point, directly use the on-site operating point to correct the on-site pump performance curve; if there are multiple on-site operating points, calculate the average operating point by the least squares method to obtain the correction parameter and then correct the on-site pump performance curve, as shown in formula (3):

[0078] f(Q, P) = f′(Q, P) + c (3)

[0079] where f(Q, P) is the final corrected on-site pump performance curve; c is the correction parameter; and according to the measured on-site operating points (Q1, P1), (Q2, P2),…, (Q j , P j ), solve for c using the least squares method, as shown in formula (4):

[0080]

[0081] where g ′ (Q i) is the explicit expression of f′(Q,P), that is, g ′ (Q i ) = P. Substitute the measured on-site operating condition points into formula (4). Specifically, substitute Q j ,P j ) into g j by substituting Q ′ (Q i ) to obtain P. Compare the P determined by the on-site pump performance curve with the measured on-site operating condition point P i to obtain the correction parameter by the least squares method.

[0082] Another specific embodiment of the present invention is as follows:

[0083] First, establish a three-dimensional model of the pump through a three-dimensional imaging scanner. Take the performance influencing factors of the pump as the test input parameters affecting the pump performance curve, and design the test input parameters using the orthogonal test method; then perform three-dimensional simulation of the pump using the professional pump software Pumplinx according to the test input parameters and the three-dimensional model to obtain the pump test performance curve; then calculate the deviation of adjacent pump test performance curves to make the maximum deviation of the adjacent curves less than 7%. If it cannot be achieved, re-adjust the level values of the test input parameters and re-simulate to obtain the adjusted pump test performance curve until the maximum deviation of the adjacent curves is less than 7%. Store these test input parameters in the database so that the database stores the test input parameters and the corresponding test performance curves.

[0084] Secondly, measure the current input parameters of the on-site pump installed by the on-site acquisition equipment to obtain the current input parameters of the on-site pump, and measure the operating condition points of the on-site pump under the current input parameters; then calculate the spatial distance between the current input parameters and the test input parameters according to formula (1), find the two sets of data with the smallest and the second smallest spatial distances between the test input parameters and the current input parameters, and calculate the weights according to the proportional rule according to formula (2) based on the smallest spatial distance and the second smallest spatial distance to obtain the performance curve of the on-site pump.

[0085] Finally, obtain the measured on-site pump operating condition points. The on-site pump operating condition points calculate the correction parameter according to the least squares method according to formula (4), and calculate the corrected final on-site pump performance curve according to formula (3) from the correction parameter.

[0086] By implementing the technical solution of the present invention, the following beneficial effects are achieved:

[0087] Adopt the on-site water pump performance curve fitting method of the present invention to establish a water pump test performance curve based on test input parameters; obtain the current input parameters of the on-site water pump; calculate the spatial distance according to the current input parameters and the test input parameters, and combine the water pump test performance curve to fit the on-site water pump performance curve to obtain the actual on-site water pump performance curve. The present invention combines simulation experiment data to fit the performance curve closest to the test points, which is beneficial for power plants to quickly and accurately fit the performance curve of water pumps during actual application, meet the on-site construction period requirements, facilitate tracking the change trend of water pump performance on-site, accurately reflect the performance of on-site water pumps, and avoid the operation safety risks caused by curve changes due to structural changes during the installation of some water pumps.

[0088] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts between the various embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and reference can be made to the description in the method part for the relevant parts.

[0089] It can be understood that the above embodiments only represent the preferred implementation modes of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent; it should be noted that for those of ordinary skill in the art, without departing from the inventive concept, the above technical features can be freely combined, and several deformations and improvements can also be made, which all belong to the protection scope of the present invention; therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

[0090] The above embodiments are only for explaining the technical concept and features of the present invention, and their purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A method for fitting the performance curve of an on-site water pump, characterized in that, It includes the following steps: S1: Establish a pump test performance curve based on test input parameters; S2: Obtain the current input parameters of the on-site pump; S3: Calculate the spatial distance according to the current input parameters and the test input parameters, and combine the pump test performance curve to fit the on-site pump performance curve; Step S3 includes: S31: Calculate the spatial distance between the current input parameters and the test input parameters to obtain two sets of data with the smallest and the second smallest spatial distances; The obtaining of the two sets of data with the smallest and the second smallest spatial distances includes: The smallest spatial distance, the test input parameters corresponding to the smallest spatial distance; The second smallest spatial distance, the test input parameters corresponding to the second smallest spatial distance; S32: Fit the on-site pump performance curve according to the two sets of data with the smallest and the second smallest spatial distances and in combination with the corresponding pump test performance curve; Step S32 further includes: Calculating weights for the smallest spatial distance and the second smallest spatial distance according to a proportional rule; Comparing the pump test performance curves corresponding to the smallest spatial distance and the second smallest spatial distance according to the weights to obtain the on-site pump performance curve.

2. The on-site water pump performance curve fitting method according to claim 1, characterized in that Step S1 includes: S11: Establish a three-dimensional model of the pump; S12: Screen and set the test input parameters according to the performance influencing factors of the pump; S13: Perform three-dimensional simulation according to the test input parameters in combination with the three-dimensional model to obtain the pump test performance curve.

3. The on-site water pump performance curve fitting method according to claim 2, characterized in that Step S13 further includes: S131: Judge whether the maximum deviation between the closest curves in the pump test performance curve obtained by simulation is less than a threshold; S132: If it is judged that the maximum deviation is not less than the threshold, readjust the test input parameters and perform simulation to obtain the adjusted pump test performance curve; S133: Repeat S131 - S132 until it is judged that the maximum deviation is less than the threshold, and then execute step S2.

4. The method for fitting the on-site pump performance curve according to claim 1, characterized in that In step S12, the orthogonal test method is used to design the test input parameters.

5. The on-site water pump performance curve fitting method according to claim 1, wherein The calculation of weights according to the proportional rule satisfies the following formula: = is the performance curve of the on-site water pump, is the performance curve of the second smallest space distance test, is the performance curve of the smallest space distance test,( 、 are the test input parameters, the smallest space distance, is the second smallest space distance, Q is the flow rate of the water pump, P is the head of the water pump.

6. The on-site water pump performance curve fitting method according to claim 1, characterized in that It further includes the following steps: Measure the on-site operating point of the on-site pump; Calculate a correction parameter according to the on-site operating point, and correct the on-site pump performance curve with the correction parameter to obtain the final on-site pump performance curve.

7. The on-site water pump performance curve fitting method according to claim 6, characterized in that The calculation of the correction parameter according to the on-site operating point, and the correction of the on-site pump performance curve with the correction parameter to obtain the final on-site pump performance curve includes: If there is only one on-site operating point, directly use the on-site operating point to correct the on-site pump performance curve; If there are multiple on-site operating points, calculate the average operating point by the least squares method to obtain the correction parameter for correcting the on-site pump performance curve.

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