Abstract:PurposeThe purpose of this study is to create a mathematical model, a numerical algorithm and a computer program for studying the vibration of composite pipelines based on the theory of beams used in the oil and gas industry, agriculture and water management, housing and communal services and other areas.Design/methodology/approachA mathematical model of vibration of a viscoelastic pipeline based on the theory of beams with a pulsating fluid flowing through it was developed. Using the Bubnov-Galerkin method, b… Show more
“…The study of equation (16) shows that it is an integral Fredholm equation of the second kind with a weak singularity. Its unique solvability follows from the uniqueness of the solution to the problem.…”
Modeling the movement of moisture in the soil is of great importance for assessing the impact of agricultural land on surface water bodies and, consequently, on the natural environment and humans. This is because huge volumes of pollutants from the fields (pesticides, mineral fertilizers, nitrates, and nutrients contained in them) are transferred to reservoirs by filtering moisture. Different methods solve all these tasks. The method of natural analogies is based on the analysis of graphs of fluctuations in groundwater level. To apply this method on irrigated lands, it is necessary to have a sufficiently studied irrigated area with similar natural, organizational and economic conditions. The successful application of this method, based on the fundamental theory of physical similarity, mainly depends on the availability of a sufficiently close comparison object, which is quite rare in practice. Physical modeling is often used to construct dams and other hydraulic structures. Previously, the method of electrical modeling was also widely used. It was further found that nonlocal boundary conditions arise in the problems of predicting soil moisture, modeling fluid filtration in porous media, mathematical modeling of laser radiation processes, and plasma physics problems, as well as mathematical biology.
“…The study of equation (16) shows that it is an integral Fredholm equation of the second kind with a weak singularity. Its unique solvability follows from the uniqueness of the solution to the problem.…”
Modeling the movement of moisture in the soil is of great importance for assessing the impact of agricultural land on surface water bodies and, consequently, on the natural environment and humans. This is because huge volumes of pollutants from the fields (pesticides, mineral fertilizers, nitrates, and nutrients contained in them) are transferred to reservoirs by filtering moisture. Different methods solve all these tasks. The method of natural analogies is based on the analysis of graphs of fluctuations in groundwater level. To apply this method on irrigated lands, it is necessary to have a sufficiently studied irrigated area with similar natural, organizational and economic conditions. The successful application of this method, based on the fundamental theory of physical similarity, mainly depends on the availability of a sufficiently close comparison object, which is quite rare in practice. Physical modeling is often used to construct dams and other hydraulic structures. Previously, the method of electrical modeling was also widely used. It was further found that nonlocal boundary conditions arise in the problems of predicting soil moisture, modeling fluid filtration in porous media, mathematical modeling of laser radiation processes, and plasma physics problems, as well as mathematical biology.
“…In addition, the fluid–solid coupling method was used to investigate the vibrations of fluid-conveying pipelines (Matta and Szasz, 2018; Chen et al , 2021b; Lin and Wang, 2019). Khudayarov and Turaev (2022) established a mathematical model of composite pipe vibration and investigated the vibration problem of a composite pipe under the action of a pulsating fluid through the established model. The results indicated that increases in material viscosity decrease the critical flow velocity that can cause pipeline vibration.…”
Purpose
Abnormal vibrations often occur in the liquid oxygen kerosene transmission pipelines of rocket engines, which seriously threaten their safety. Improper handling can result in failed rocket launches and significant economic losses. Therefore, this paper aims to examine vibrations in transmission pipelines.
Design/methodology/approach
In this study, a three-dimensional high-pressure pipeline model composed of corrugated pipes, multi-section bent pipes, and other auxiliary structures was established. The fluid–solid coupling method was used to analyse vibration characteristics of the pipeline under various external excitations. The simulation results were visualised using MATLAB, and their validity was verified via a thermal test.
Findings
In this study, the vibration mechanism of a complex high-pressure pipeline was examined via a visualisation method. The results showed that the low-frequency vibration of the pipe was caused by fluid self-excited pressure pulsation, whereas the vibration of the engine system caused a high-frequency vibration of the pipeline. The excitation of external pressure pulses did not significantly affect the vibrations of the pipelines. The visualisation results indicated that the severe vibration position of the pipeline thermal test is mainly concentrated between the inlet and outlet and between the two bellows.
Practical implications
The results of this study aid in understanding the causes of abnormal vibrations in rocket engine pipelines.
Originality/value
The causes of different vibration frequencies in the complex pipelines of rocket engines and the propagation characteristics of external vibration excitation were obtained.
“…The causes of vibration in the piping of the main line pumps and the influence of frequency regulation on the level of vibration of the main line pump are analyzed. B Khudayarov [8] developed a computational algorithm for solving problems of vibrations in composite pipelines conveying pulsating liquid. The stability and amplitude-time characteristics of vibration in composite pipelines with pulsating fluid flowing in them are studied for a wide range of changes in the parameters of deformable systems and fluid flow.…”
Branched hydraulic lines are prone to leakage and break under complex working conditions. The coupling vibration problem caused by the fluid pressure beat and external mechanical excitation of the pump at the junction of the branch of the cross-type hydraulic pipeline is very common. So a method combining finite element simulation and fluid-structure interaction vibration experiments is proposed for research. First, the possibility of the finite element method in solving the pipeline vibration problem is verified, and then the modal analysis and harmonious response analysis of the cross-type pipe are carried out to discuss the influence of fluid pressure and solid elastic modulus on pipeline vibration. The results show that as the fluid pressure and pipeline elastic modulus change, different modes of different orders will be affected. Under external excitation, only a portion of the order is sensitive to external excitation.
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