Method and device for judging changes in roughness of natural gas flow metering pipe wall

Abstract

The present invention discloses a method and device for judging the change in roughness of a natural gas flow meter pipe wall, comprising the following steps: obtaining an ultrasonic flow meter type, a sound channel layout structure, and the flow velocity of each sound channel; converting the flow velocity of each sound channel into a pipe diameter sound channel flow velocity based on the type of the ultrasonic flow meter, its sound channel layout structure, and the distribution characteristics of a fully developed turbulent flow field; constructing new pipe wall roughness change characteristics and sound channel flow velocity characteristics based on the flow velocity of each sound channel according to the occurrence of the change in the roughness of the natural gas flow meter pipe wall; normalizing the constructed pipe wall roughness change characteristics and sound channel flow velocity characteristics based on the converted pipe diameter flow velocity; training a natural gas flow meter pipe wall roughness change judgment model based on the normalized pipe wall roughness change characteristics and sound channel flow velocity characteristics using an isolation forest method; and judging whether the natural gas flow meter pipe wall has undergone a roughness change using the natural gas flow meter pipe wall roughness change judgment model.

Description

Technical Field

[0001] The present application relates to the field of energy and power engineering technology, and in particular to a method and device for determining changes in the roughness of a natural gas flow metering pipe wall. Background Art

[0002] As a clean and efficient energy source, the demand for natural gas in various industries is constantly increasing.

[0003] The vast majority of gaseous natural gas is measured and traded primarily through pipelines. Therefore, ensuring accurate pipeline natural gas metering is crucial for the development, transportation, and trade of natural gas resources. However, due to the long-term, continuous nature of pipeline natural gas metering, which often precludes repeated measurements, any deviations in the natural gas metering system, if accumulated over time, can lead to severe economic losses and numerous trade disputes. Therefore, the accuracy of natural gas metering is directly linked to the interests of both parties involved in the trade. Improving the accuracy of natural gas metering has become a key issue that must be addressed in pipeline natural gas transportation.

[0004] Ultrasonic flowmeters, as an advanced technology in pipeline natural gas metering, offer advantages such as non-contact measurement, high repeatability, a wide measurement range, simple operation, bidirectional measurement, and convenient installation. In recent years, this technology has been widely adopted. With the rapid development of electronic technology, ultrasonic flowmeters have also made significant progress.

[0005] Ultrasonic flowmeters are velocity-based flow instruments whose measurement principle relies on the assumption that the measured flow field is in a fully developed, uniform, and stable state. However, in complex natural gas metering sites, the measurement accuracy of ultrasonic flowmeters can be significantly affected by the flow field within the pipeline. For example, if the roughness of the inner wall of the upstream straight pipe section of the flowmeter changes, the flowmeter in operation may experience performance deviations, thereby affecting the ultrasonic flowmeter's measurement accuracy. Therefore, it is particularly important to investigate whether the roughness of the natural gas flow meter pipe wall changes. Summary of the Invention

[0006] The purpose of the embodiments of the present application is to provide a method and device for determining changes in the roughness of a natural gas flow metering pipe wall, so as to address the deficiency in the prior art in that it is difficult to accurately determine whether a metering performance deviation exists.

[0007] According to a first aspect of an embodiment of the present application, a method for determining a change in roughness of a natural gas flow metering pipe wall is provided, comprising:

[0008] Obtain the ultrasonic flowmeter type, channel layout structure, and flow rate of each channel;

[0009] Based on the ultrasonic flowmeter type and its channel layout structure, combined with the turbulent flow field distribution characteristics, the flow velocity of each channel is converted into the channel flow velocity of the pipe diameter;

[0010] According to the change of pipe wall roughness in natural gas flow measurement, the new pipe wall roughness change characteristics and acoustic channel velocity characteristics are constructed using the flow velocity of each acoustic channel of the ultrasonic flowmeter.

[0011] According to the converted pipe diameter acoustic channel velocity, the constructed pipe wall roughness variation characteristics and acoustic channel velocity characteristics are normalized;

[0012] Based on the normalized pipe wall roughness variation characteristics and acoustic channel velocity characteristics, the isolation forest method was used to train a natural gas flow meter pipe wall roughness variation judgment model.

[0013] The natural gas flow metering pipe wall roughness change judgment model is used to judge whether the natural gas metering pipe wall has a roughness change, and a judgment result is obtained.

[0014] According to a second aspect of an embodiment of the present application, a device for determining changes in roughness of a natural gas flow metering pipe wall is provided, comprising:

[0015] An acquisition module is used to obtain the ultrasonic flowmeter type, channel layout structure, and flow rate of each channel;

[0016] The conversion module is used to convert the flow velocity of each channel into the flow velocity of the pipe diameter channel based on the type of ultrasonic flowmeter and its channel layout structure, combined with the distribution characteristics of the turbulent flow field;

[0017] A construction module is used to construct new pipe wall roughness change characteristics and acoustic channel flow velocity characteristics based on the change of pipe wall roughness during natural gas flow measurement and the flow velocity of each acoustic channel of the ultrasonic flowmeter;

[0018] A normalization module is used to normalize the constructed pipe wall roughness variation characteristics and acoustic channel flow velocity characteristics according to the converted pipe diameter acoustic channel flow velocity;

[0019] A modeling module is used to train a natural gas flow meter pipe wall roughness change judgment model based on the normalized pipe wall roughness change characteristics and acoustic channel velocity characteristics using the isolation forest method;

[0020] The judgment module is used to use the natural gas flow metering pipe wall roughness change judgment model to judge whether the natural gas metering pipe wall has a roughness change and obtain a judgment result.

[0021] According to a third aspect of the embodiments of the present application, there is provided an electronic device, including:

[0022] one or more processors;

[0023] a memory for storing one or more programs;

[0024] When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in the first aspect.

[0025] According to a fourth aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which computer instructions are stored. When the instructions are executed by a processor, the steps of the method described in the first aspect are implemented.

[0026] The technical solutions provided by the embodiments of the present application may have the following beneficial effects:

[0027] As can be seen from the above embodiments, based on the ultrasonic flowmeter type, its acoustic channel layout structure, and the fully developed turbulent flow field distribution characteristics, this application converts the flow velocity of each acoustic channel into the flow velocity of the pipe diameter and constructs new pipe wall roughness variation characteristics and acoustic channel velocity characteristics. These constructed pipe wall roughness variation characteristics and acoustic channel velocity characteristics are then normalized. Based on these normalized pipe wall roughness variation characteristics and acoustic channel velocity characteristics, an isolation forest method is used to train a natural gas flow meter pipe wall roughness variation judgment model. Finally, by inputting the ultrasonic flowmeter state parameters and acoustic channel velocity, a judgment can be made as to whether the natural gas meter pipe wall has undergone a roughness change. When the natural gas flow meter pipe wall undergoes a roughness change, this invention analyzes and mines new pipe wall roughness variation characteristics and acoustic channel velocity characteristics, and uses machine learning methods to determine whether the natural gas flow meter pipe wall has undergone a roughness change. This has important practical significance for ensuring the accuracy of natural gas metering and safeguarding the common interests of both trading parties.

[0028] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] Figure 1 The present invention is a flow chart of a method for determining changes in the roughness of a natural gas flow metering pipe wall according to an exemplary embodiment.

[0031] Figure 2 The present invention is a block diagram of a device for determining changes in the roughness of a natural gas flow metering pipe wall according to an exemplary embodiment. DETAILED DESCRIPTION

[0032] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0033] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0034] Figure 1 FIG. 1 is a flow chart showing a method for determining a change in the roughness of a natural gas flow metering pipe wall according to an exemplary embodiment. Figure 1 As shown, the method may include the following steps:

[0035] S1: Obtain the ultrasonic flowmeter type, channel layout structure, and flow rate of each channel;

[0036] Specifically, the ultrasonic flowmeter type is an insertion type ultrasonic flowmeter, and the channel layout is a multi-channel opposed-beam layout and a multi-channel reflective layout, including a four-channel opposed-beam layout, a four-channel reflective layout, a six-channel reflective layout and a six-channel opposed-beam layout, etc. The flow velocity of each channel is the average flow velocity data on each channel of the ultrasonic flowmeter.

[0037] S2: Based on the ultrasonic flowmeter type and its channel layout structure, combined with the turbulent flow field distribution characteristics, the flow velocity of each channel is converted into the channel flow velocity of the pipe diameter;

[0038] Specifically, based on the ultrasonic flowmeter type and ultrasonic flowmeter sound channel layout structure, combined with the turbulent flow field distribution characteristics, the circular pipe turbulent flow velocity distribution index formula is used to calculate the distance from the pipe diameter. chordal channel velocity at :

[0039]

[0040] in, It is half of the central angle of the pipe corresponding to the chord channel. It represents the distance between a point on the chord channel and the center of the chord channel. is the maximum flow velocity at the pipe axis, is the radius of the tube, is the experience index, is the flow velocity at a certain point in the pipe, and the formula for the turbulent flow velocity distribution index of the circular pipe is:

[0041]

[0042] when = 0, the calculated chordal channel velocity is the pipe diameter channel velocity, that is,

[0043]

[0044] According to the above two formulas, the flow velocity of each channel can be converted to the flow velocity at the pipe diameter. Radiated sound channels and Reflective channels, of which , ,…, Respectively The flow rate of the opposite channel, , ,…, Respectively The velocity of the reflective channel, and are all even numbers, and the converted flow velocities of each channel are expressed as , ,…, and , ,…, ;

[0045] Converting the flow velocity of each channel into the channel flow velocity of the pipe diameter is conducive to comparing the flow velocities of each channel and is conducive to the next step of constructing new pipe wall roughness change characteristics and channel flow velocity characteristics.

[0046] S3: Based on the roughness change of the natural gas flow meter pipe wall, a new pipe wall roughness change feature and acoustic channel flow velocity feature are constructed;

[0047] Specifically, according to the flow velocity of each channel, a new pipe wall roughness variation feature is constructed :

[0048]

[0049]

[0050]

[0051] Among them, the ultrasonic flow meter contains multiple sound channels at different positions. Each type of ultrasonic flow meter contains a radial sound channel and a sound channel at a certain distance from the pipe diameter. represents the number of radial channels, Represent the flow velocity of each radial channel, It represents the average value of the flow velocity in each radial channel, represents the number of non-radial channels, Represent the flow velocity of each non-radial channel, It represents the average value of the flow velocity in each non-radial channel, is the pipe wall roughness variation characteristic constructed based on the flow velocities of all acoustic channels of this model;

[0052] The new pipe wall roughness variation characteristics can well describe the variation degree of pipe wall roughness for natural gas flow measurement;

[0053] Specifically, according to the flow velocity of each channel, the channel flow velocity characteristics are constructed ;

[0054] More specifically, The selection and construction of is as follows:

[0055] for or The ultrasonic flowmeter directly selects all converted acoustic channel velocity characteristics, which can be specifically expressed as , , , ;for The ultrasonic flowmeter can be expressed as , , , ;for The ultrasonic flowmeter directly selects all converted acoustic channel velocity characteristics, which can be specifically expressed as , , , , , .

[0056] According to the above-mentioned characteristics and selection methods of the flow velocity of each channel of various ultrasonic flowmeter types and channel layouts, those skilled in the art can choose ,or ,or The flow velocity of each channel of the ultrasonic flowmeter is constructed and selected in a similar manner, and is not limited to the above examples.

[0057] Constructed acoustic channel flow velocity characteristics , which can better capture the patterns and relationships in the data. By converting, extracting and combining the original vocal tract flow velocity data, new features are generated to more accurately express the original vocal tract flow velocity, thereby improving the performance of the model.

[0058] S4: Based on the converted pipe diameter velocity, the constructed new pipe wall roughness variation characteristics and acoustic channel velocity characteristics are normalized;

[0059] Specifically, the average of all converted acoustic duct flow velocities is calculated , divide the selected and constructed vocal tract velocity characteristics by , we can get the dimensionless acoustic channel velocity, which is calculated as follows:

[0060]

[0061] The dimensionless acoustic channel velocity characteristic can be expressed as:

[0062]

[0063] in, is the velocity characteristic of the vocal tract;

[0064] After obtaining the dimensionless acoustic channel velocity, and the constructed pipe wall roughness variation characteristics Perform normalization processing, the normalization processing formula is as follows:

[0065]

[0066]

[0067] in, represents the dimensionless acoustic channel velocity characteristic, To construct the wall roughness variation characteristics, and represent the maximum and minimum values ​​of the dimensionless acoustic channel velocity characteristics, respectively. is the normalized vocal tract velocity characteristic, and Respectively represent the maximum and minimum values ​​of the pipe wall roughness variation characteristics, is the variation characteristics of pipe wall roughness after normalization;

[0068] After normalization, data with different feature ranges can be unified into the same range to avoid certain features from having too much influence on the loss function. This can speed up the model training process, increase the convergence speed, and avoid the impact of value differences between different features on subsequent model training.

[0069] S5: Based on the normalized acoustic channel velocity characteristics and pipe wall roughness variation characteristics, the isolation forest method is used to train a natural gas flow meter pipe wall roughness variation judgment model.

[0070] Specifically, according to different ultrasonic flowmeter types, the natural gas flow meter wall roughness change judgment model includes three sub-judgment models, namely sub-judgment model 1, sub-judgment model 2 and sub-judgment model 3;

[0071] For sub-judgment model 1, take Radiated sound channels and Normalized channel velocity characteristics of ultrasonic flowmeter with a reflective channel and the change characteristics of pipe wall roughness after normalization Training obtained;

[0072] For sub-judgment model 2, take Radiated sound channels and Normalized channel velocity characteristics corresponding to a reflection channel ultrasonic flowmeter and the change characteristics of pipe wall roughness after normalization 、 Radiated sound channels and Normalized channel velocity characteristics of ultrasonic flowmeter with a reflective channel and the change characteristics of pipe wall roughness after normalization Training obtained;

[0073] For sub-judgment model 3, take Normalized channel velocity characteristics of an ultrasonic flowmeter with a beam channel and the change characteristics of pipe wall roughness after normalization Training obtained;

[0074] After each sub-judgment model is trained, the trained sub-judgment model can be used to judge whether the roughness change occurs on the natural gas metering pipe wall.

[0075] S6: using the natural gas flow metering pipe wall roughness change judgment model to judge whether the natural gas metering pipe wall has a roughness change;

[0076] Specifically, the ultrasonic flowmeter type, acoustic channel layout structure and all acoustic channel flow rates are input into the natural gas flow meter pipe wall roughness change judgment model to determine whether the natural gas pipeline has a roughness change;

[0077] for The ultrasonic flowmeter with a beam-type sound channel can input the corresponding sound channel flow rate into the sub-judgment model 1 to obtain the judgment result;

[0078] for Radiated sound channels and The ultrasonic flowmeter with a reflective sound channel can input its corresponding sound channel flow velocity into the sub-judgment model 2 to obtain the judgment result;

[0079] for Radiated sound channels and The ultrasonic flowmeter with a reflective sound channel can input its corresponding sound channel flow velocity into the sub-judgment model 2 to obtain the judgment result;

[0080] for The ultrasonic flowmeter with a beam-type sound channel can input its corresponding sound channel flow rate into the sub-judgment model 3 to obtain the judgment result.

[0081] In this implementation, 70 sets of real-flow test data from a natural gas metering station in China and 61 sets of pipe wall roughness variation data obtained through CFD simulation were selected. The 70 sets of real-flow test data were used to train a natural gas flow meter pipe wall roughness variation prediction model, while the 61 sets of CFD simulation roughness variation data were used for testing. Conditions with a roughness greater than or equal to 0.4 were considered to indicate a roughness variation.

[0082] The detection effect of the model is evaluated using statistical indicators such as Accuracy, Precision, and Recall. The calculation method of the three indicators is as follows:

[0083]

[0084]

[0085]

[0086] in, Indicates the number of samples with roughness changes that are correctly identified as samples with roughness changes. It indicates the number of normal samples that are correctly identified as normal samples. Indicates the number of normal samples that are mistakenly identified as samples with roughness changes. Indicates the number of samples with roughness changes that are mistakenly identified as normal samples.

[0087] Table 1 Test results of the natural gas flow metering pipe wall roughness change judgment model

[0088] True positive (TP) True negative (TN) False positive (FP) False negative (FN) 23 31 7 0

[0089] Among them, the precision rate is 0.885, the accuracy rate is 0.767, and the recall rate is 1, which shows the effectiveness of the model.

[0090] Corresponding to the aforementioned embodiment of the method for determining changes in the roughness of a natural gas flow metering pipe wall, the present application also provides an embodiment of a device for determining changes in the roughness of a natural gas flow metering pipe wall.

[0091] Figure 2 This is a block diagram of a device for determining the roughness change of a natural gas flow meter pipe wall according to an exemplary embodiment. Figure 2 , the device comprises:

[0092] Acquisition module 1, used to obtain the ultrasonic flowmeter type, channel layout structure and flow rate of each channel;

[0093] Conversion module 2 is used to convert the flow velocity of each channel into the channel flow velocity of the pipe diameter based on the type of ultrasonic flowmeter and its channel layout structure, combined with the distribution characteristics of the turbulent flow field;

[0094] Building module 3, for constructing new pipe wall roughness change characteristics and acoustic channel flow velocity characteristics based on the change of pipe wall roughness measured by natural gas flow, using the flow velocity of each acoustic channel of the ultrasonic flowmeter;

[0095] Normalization module 4, used for normalizing the constructed pipe wall roughness variation characteristics and acoustic channel velocity characteristics according to the converted pipe diameter acoustic channel velocity;

[0096] Modeling module 5 is used to train a natural gas flow meter pipe wall roughness change judgment model based on the normalized pipe wall roughness change characteristics and the acoustic channel flow velocity characteristics using the isolation forest method;

[0097] The judgment module 6 is used to use the natural gas flow metering pipe wall roughness change judgment model to judge whether the natural gas metering pipe wall has a roughness change and obtain a judgment result.

[0098] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0099] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to the partial description of the method embodiments. The device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present application scheme. A person of ordinary skill in the art can understand and implement it without paying any creative work.

[0100] Correspondingly, the present application also provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned method for judging the roughness change of the natural gas flow meter pipe wall.

[0101] Accordingly, the present application also provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the above-mentioned method for determining the change in the roughness of the natural gas flow metering pipe wall.

[0102] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the contents disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered merely as exemplary, and the true scope and spirit of the present application are indicated by the claims.

[0103] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for determining the roughness change of a natural gas flow meter pipe wall, characterized in that: include: Obtain the ultrasonic flowmeter type, channel layout structure, and flow rate of each channel; Based on the ultrasonic flowmeter type and its channel layout structure, combined with the turbulent flow field distribution characteristics, the flow velocity of each channel is converted into the channel flow velocity of the pipe diameter; According to the change of pipe wall roughness in natural gas flow measurement, the new pipe wall roughness change characteristics and acoustic channel velocity characteristics are constructed using the flow velocity of each acoustic channel of the ultrasonic flowmeter. According to the converted pipe diameter acoustic channel velocity, the constructed pipe wall roughness variation characteristics and acoustic channel velocity characteristics are normalized; Based on the normalized pipe wall roughness variation characteristics and acoustic channel velocity characteristics, the isolation forest method was used to train a natural gas flow meter pipe wall roughness variation judgment model. The natural gas flow metering pipe wall roughness change judgment model is used to judge whether the natural gas metering pipe wall has a roughness change, and a judgment result is obtained.

2. The method according to claim 1, characterized in that Based on the ultrasonic flowmeter type and its channel layout structure, combined with the turbulent flow field distribution characteristics, the flow velocity of each channel is converted into the channel flow velocity of the pipe diameter, including: Based on the ultrasonic flowmeter type and ultrasonic flowmeter sound channel layout structure, combined with the turbulent flow field distribution characteristics, the distance from the pipe diameter is calculated by the circular pipe turbulent flow velocity distribution index formula. chordal channel velocity at ; in, It is half of the central angle of the pipe corresponding to the chord channel. It represents the distance between a point on the chord channel and the center of the chord channel. is the maximum flow velocity at the pipe axis, is the radius of the tube, is the experience index, is the flow velocity at a certain point in the pipe, and the formula for the turbulent flow velocity distribution index of the circular pipe is: when =0, the calculated chordal channel velocity is the pipe diameter channel velocity, that is: Ultrasonic flow meter includes Radiated sound channels and Reflective channels, of which , ,…, Respectively The flow rate of the opposite channel, , ,…, Respectively The velocity of the reflective channel, and are all even numbers, and the converted flow velocities of each channel are expressed as , ,…, and , ,…, ; According to the above two formulas, the flow velocity of each sound channel is converted to the flow velocity at the pipe diameter.

3. The method according to claim 1, characterized in that According to the changes in the roughness of the natural gas flow meter pipe wall, new pipe wall roughness change characteristics and acoustic channel flow velocity characteristics are constructed, including: According to the flow velocity of each channel, a new pipe wall roughness variation feature is constructed ; Among them, the ultrasonic flow meter contains multiple sound channels at different positions. Each type of ultrasonic flow meter contains a radial sound channel and a sound channel at a certain distance from the pipe diameter. represents the number of radial channels, Represent the flow velocity of each radial channel, It represents the average value of the flow velocity in each radial channel, represents the number of non-radial channels, Represent the flow velocity of each non-radial channel, It represents the average value of the flow velocity in each non-radial channel, is the pipe wall roughness variation characteristic constructed based on the flow velocities of all acoustic channels of this model; According to the flow velocity of each channel, construct the channel flow velocity characteristics .

4. The method according to claim 3, characterized in that Acoustic channel flow velocity characteristics The selection and construction of is as follows: for or The ultrasonic flowmeter directly selects all converted acoustic channel velocity characteristics, which can be specifically expressed as , , , ;for The ultrasonic flowmeter can be expressed as , , , ;for The ultrasonic flowmeter directly selects all converted acoustic channel velocity characteristics, which can be specifically expressed as , , , , , .

5. The method according to claim 1, wherein According to the converted pipe diameter velocity, the constructed new pipe wall roughness variation characteristics and acoustic channel velocity characteristics are normalized, including: Calculate the average of all converted duct flow velocities , divide the selected and constructed vocal tract velocity features by the average value , we can get the dimensionless acoustic channel velocity, which is calculated as follows: Dimensionless acoustic channel velocity characteristics Expressed as: in, is the velocity characteristic of the vocal tract; The dimensionless acoustic channel velocity and pipe wall roughness variation characteristics Perform normalization processing, the normalization processing formula is as follows: in, represents the dimensionless acoustic channel velocity characteristic, To construct the wall roughness variation characteristics, and represent the maximum and minimum values ​​of the dimensionless acoustic channel velocity characteristics, respectively. is the normalized vocal tract velocity characteristic, and Respectively represent the maximum and minimum values ​​of the pipe wall roughness variation characteristics, is the variation characteristics of pipe wall roughness after normalization.

6. The method according to claim 1, characterized in that The natural gas flow metering pipe wall roughness change judgment model includes three sub-judgment models, namely sub-judgment model 1, sub-judgment model 2 and sub-judgment model 3; For sub-judgment model 1, take Radiated sound channels and Normalized channel velocity characteristics of ultrasonic flowmeter with a reflective channel and the change characteristics of pipe wall roughness after normalization Training obtained; For sub-judgment model 2, take Radiated sound channels and Normalized channel velocity characteristics corresponding to a reflection channel ultrasonic flowmeter and the change characteristics of pipe wall roughness after normalization 、 Radiated sound channels and Normalized channel velocity characteristics of ultrasonic flowmeter with a reflective channel and the change characteristics of pipe wall roughness after normalization Training obtained; For sub-judgment model 3, take Normalized channel velocity characteristics of an ultrasonic flowmeter with a beam channel and the change characteristics of pipe wall roughness after normalization Trained to get.

7. The method according to claim 6, characterized in that The natural gas flow metering pipe wall roughness change judgment model is used to judge whether the natural gas metering pipe wall has a roughness change, including: Inputting the ultrasonic flowmeter type, acoustic channel layout structure and all acoustic channel flow rates into the natural gas flow meter pipe wall roughness change judgment model can determine whether the natural gas pipeline has a roughness change; for The ultrasonic flowmeter with a beam-type sound channel can input the corresponding sound channel flow rate into the sub-judgment model 1 to obtain the judgment result; for Radiated sound channels and The ultrasonic flowmeter with a reflective sound channel can input its corresponding sound channel flow velocity into the sub-judgment model 2 to obtain the judgment result; for Radiated sound channels and The ultrasonic flowmeter with a reflective sound channel can input its corresponding sound channel flow velocity into the sub-judgment model 2 to obtain the judgment result; for The ultrasonic flowmeter with a beam-type sound channel can input its corresponding sound channel flow rate into the sub-judgment model 3 to obtain the judgment result.

8. A device for judging the change in roughness of a natural gas flow meter pipe wall, characterized in that: include: An acquisition module is used to obtain the ultrasonic flowmeter type, channel layout structure, and flow rate of each channel; The conversion module is used to convert the flow velocity of each channel into the flow velocity of the pipe diameter channel based on the type of ultrasonic flowmeter and its channel layout structure, combined with the distribution characteristics of the turbulent flow field; A construction module is used to construct new pipe wall roughness change characteristics and acoustic channel flow velocity characteristics based on the change of pipe wall roughness during natural gas flow measurement and the flow velocity of each acoustic channel of the ultrasonic flowmeter; A normalization module is used to normalize the constructed pipe wall roughness variation characteristics and acoustic channel flow velocity characteristics according to the converted pipe diameter acoustic channel flow velocity; A modeling module is used to train a natural gas flow meter pipe wall roughness change judgment model based on the normalized pipe wall roughness change characteristics and acoustic channel velocity characteristics using the isolation forest method; The judgment module is used to use the natural gas flow metering pipe wall roughness change judgment model to judge whether the natural gas metering pipe wall has a roughness change and obtain a judgment result.

9. An electronic device, characterized in that: include: one or more processors; a memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the instruction is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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