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Project titleFundamental principles of application of fractal analysis methods for vibroacoustic control of pipelines

AffiliationFederal state budgetary educational institution of higher education "KAZAN STATE POWER ENGINEERING UNIVERSITY",

Research area 09 - ENGINEERING SCIENCES, 09-406 - Energy saving in transmission and consumption of power

Keywordsheat supply systems, reliability, energy saving, energy efficiency, diagnostics, leak, defect, pipelines, acoustic signal, fractal analysis

Annotation
Pipelines are structural elements of many systems. They are used in chemical production enterprises, aircraft manufacturing, oil and gas industry, in water supply and heat supply systems, etc. Accidents of pipeline systems lead to significant economic damage. According to the Ministry of Energy of the Russian Federation, the number of emergencies on the main heating networks operated by the subjects of the electric power industry (TGC and JSC-energo) has been steadily growing in recent years. In the Energy Strategy of Russia, as well as Federal Law No. 190-FZ "On Heat Supply ...", one of the priority areas of energy development is to increase the reliability of heat supply, as well as to reduce heat losses during the transportation of coolant. An important factor in ensuring the reliability of energy transportation systems is the assessment of the actual technical condition of pipelines. Methods of assessing the condition of pipeline systems by their vibroacoustic parameters are widely used today. The vibration signal has a sufficiently capacious information about the state of the object of control. To ensure the effective use of vibration diagnostics, it is necessary that this information is properly extracted from the vibration signals. Traditionally, the Fourier transform is used to process vibration signals. Undoubtedly, this is not enough. The Fourier transform is based on the assumption of the periodicity of the studied processes, which reduces the reliability of the control. As a rule, the task of analyzing vibroacoustic signals is based on the search for resonances and periodic oscillations, everything else is designated by the term "noise". However, in pipeline systems in which liquid or gas is moving, there are always complex disordered oscillations caused by flow turbulence. The theory of fractal sets can be successfully used to study such oscillatory processes. The use of fractal theory methods will allow extracting additional information about the degree of stochasticity of processes from vibroacoustic signals, thereby increasing the reliability of diagnosing pipeline systems. This, in turn, will lead to an increase in the reliability and energy efficiency of energy transport systems, including a reduction in the costs of eliminating accidents, reducing losses and saving primary energy resources. The scientific novelty is: - in substantiating the possibility of using methods of fractal analysis of vibroacoustic vibrations of pipelines to assess their technical condition; - in determining the dependence of the change in the degree of stochasticity of vibroacoustic vibrations of pipelines on the size of the leak and the nature of the flow in them. The proposed project is located at the junction of industrial control technologies, fluid mechanics and deformable solids, nonlinear dynamics, and will allow developing a new unique technique for assessing the technical condition. The interdisciplinarity of research significantly raises the fundamental importance of their results for these sciences, and also provides a scientific basis for the introduction of a modern monitoring system of pipeline networks in the territory of the Russian Federation.

Expected results
An extensive cycle of experimental and numerical studies will be carried out, including measurements of pipeline vibration signals and CFD modeling (Computational Fluid Dynamics modeling). During the implementation of the project, the following main results will be obtained: 1. The most optimal method for determining fractal characteristics for solving the problem of vibroacoustic control of pipelines will be determined for the first time. 2. An algorithm will be developed and software for analyzing the fractal properties of vibroacoustic vibrations will be created. 3. An experimental stand will be developed and created that allows conducting research on pipes of different diameters with different sizes of defects (leaks). 4. Experimental studies will be conducted on defect-free and defective pipelines 5. The influence of leaks on the degree of stochasticity of vibroacoustic vibrations of pipelines on the nature of fluid flow in them will be studied for the first time. 5. Studies of the influence of leaks on the flow characteristics (velocity, pressure, intensity of vortex formation, etc.) will be carried out using finite element analysis methods. 6. A unique methodology for assessing the technical condition of pipelines based on the analysis of fractal characteristics of vibroacoustic vibrations will be developed. 7. The developed methodology for assessing the technical condition of pipelines on existing pipeline systems will be tested and the effectiveness of the proposed solutions will be evaluated. Most of the work under the proposed project will be carried out for the first time, so the scientific results obtained will be comparable in their level with the world. The research will serve as a scientific basis for the development of monitoring systems for the technical condition of pipelines and the creation of "smart" pipeline networks. The concept of "smart" energy is supported by all developed countries and is a global trend. Comprehensive modernization of heat supply and the development of "smart grids" are also provided for in the Energy Strategy of the Russian Federation. From a practical point of view, the results of the work should give a high economic effect associated with reducing the costs of eliminating accidents in power supply systems and reducing energy losses.

Annotation of the results obtained in 2022
Description of the work performed in the reporting period: The following methods of fractal analysis of vibroacoustic signals of pipelines are considered: the method of normalized span (R/S method), the method of detrended fluctuation Analysis (DFA), the method of determining fractal dimension by power spectra, the method of multifractal Detrended fluctuation Analysis (MFDFA). An application has been submitted for obtaining a certificate of state registration of a computer program: "Program of detrended fluctuation analysis" (application No. 2023618864 dated 05/04/2023). An application has been submitted for a certificate of state registration of a computer program: "Multifractal analysis program. Version 1" (application No. 2023618814 dated 04.05.2023). An application has been submitted for a certificate of state registration of a computer program: "Multifractal analysis program. Version 2" (application No. 2023618852 dated 05/04/2023). A program implementing the methods of "identification scales" is written in the LabVIEW programming environment. The spectral analysis program is written in the LabVIEW programming environment. An experimental stand has been developed and created that allows conducting research on pipes of different diameters with different sizes of defects (leaks). Experiments were carried out on steel pipes with an external diameter of 34 mm and 159 mm. The research team took full-time part in two conferences, according to the results of the presentation received a diploma of the first degree. Description of the obtained scientific results: It has been experimentally established that using the methods of normalized span (R/S method) and detrended fluctuation analysis (DFA method), it is possible to determine the presence of pipeline leakage. It is established that the most informative are vibroacoustic signals recorded in the longitudinal direction relative to the axis of the pipeline. The dependences of the Hurst index on the diameter of the defect at different pump discharge pressures on pipes of large and small diameters are obtained. It has been established that at small leakage sizes, vibroacoustic signals are aniperstant (Hearst index H < 0.5). With an increase in the size of the defect, the Hurst index increases (becomes persistent) and, with large leaks, tends to the level of the deterministic signal (to the level H = 1). It was found that with increasing pressure, the sensitivity to detecting small leaks decreases. It is established that when using DFA methods of different order, the values of the Hurst exponent depend on the choice of the degree of the approximating polynomial. The use of a high-order polynomial leads to a decrease in the reliability of the control. It is established that the multifractal spectra of vibroacoustic signals can differ significantly from the different values of leaks and pressure in the pipeline.

Publications

1. Ayrat Zagretdinov, Shamil Ziganshin, Yuri Vankov, Eugenia Izmailova, Alexander Kondratiev Determination of Pipeline Leaks Based on the Analysis the Hurst Exponent of Acoustic Signals Water, 14(19), 3190 (year - 2022) https://doi.org/10.3390/w14193190

2. Klyukin I.I. Контроль утечек трубопроводов по анализу фрактальной размерности виброакустических сигналов Сборник материалов докладов Международной молодежной научной конференции Тинчуринские чтения-2023 "Энергетика и цифровая трансформация", - (year - 2023)

3. Klyukin I.I. Влияние порядка аппроксимирующего полинома на результаты флуктуационного анализа акустических сигналов утечек трубопровода Сборник материалов докладов Международной молодежной научной конференции Тинчуринские чтения-2023 "Энергетика и цифровая трансформация", - (year - 2023)

4. Zagretdinov A. R., Ziganshin Sh. G., Izmailova E. V., Klyukin I. I. Анализ масштабной инвариантности виброакустических сигналов трубопровода с утечками 78-я Научно-техническая конференция Санкт-Петербургского НТО РЭС им. А.С. Попова, посвященная Дню радио. Сборник материалов., 78-я Научно-техническая конференция Санкт-Петербургского НТО РЭС им. А.С. Попова, посвященная Дню радио. Сборник материалов. СПб: СПбГЭТУ «ЛЭТИ», 2023. С. 88-90. (year - 2023)

5. - Программа детрендированного флуктуационного анализа -, заявка №2023618864 (year - )

6. - Программа мультифрактального анализа. Версия 1 -, заявка №2023618814 (year - )

7. - Программа мультифрактального анализа. Версия 2 -, заявка № 2023618852 (year - )