Mathematical Model of Control-Restoration Measures on Linear Part of Main Gas Pipeline

2005 ◽  
Vol 1 (5) ◽  
pp. 117-122
Author(s):  
V. Ya. Grudz ◽  
Keyword(s):  
Mathematical Model ◽  
Linear Part ◽  
Gas Pipeline ◽  
Restoration Measures ◽  
Main Gas Pipeline

scholarly journals MODELING COMPUTATIONAL FLUID DYNAMICS OF MULTIPHASE FLOWS IN ELBOW AND T-JUNCTION OF THE MAIN GAS PIPELINE

Transport ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Yaroslav Doroshenko ◽  
Julia Doroshenko ◽  
Vasyl Zapukhliak ◽  
Lyubomyr Poberezhny ◽  
Pavlo Maruschak
Keyword(s):  
Natural Gas ◽  
Multiphase Flows ◽  
Linear Part ◽  
Erosive Wear ◽  
Gas Pipeline ◽  
Solid Particles ◽  
Ansys Fluent ◽  
Gas Main ◽  
Discrete Phase ◽  
Main Gas Pipeline

The research was performed in order to obtain the physical picture of the movement of condensed droplets and solid particles in the flow of natural gas in elbows and T-junctions of the linear part of the main gas pipeline. 3D modeling of the elbow and T-junction was performed in the linear part of the gas main, in particular, in places where a complex movement of multiphase flows occurs and changes its direction. In these places also occur swirls, collisions of discrete phases in the pipeline wall, and erosive wear of the pipe wall. Based on Lagrangian approach (Discrete Phase Model – DPM), methods of computer modeling were developed to simulate multiphase flow movement in the elbow and T-junction of the linear part of the gas main using software package ANSYS Fluent R17.0 Academic. The mathematical model is based on solving the Navier–Stokes equations, and the equations of continuity and discrete phase movement closed with Launder–Sharma (k–e) two-parameter turbulence model with appropriate initial and boundary conditions. In T-junction, we simulated gas movement in the run-pipe, and the passage of the part of flow into the branch. The simulation results were visualized in postprocessor ANSYS Fluent R17.0 Academic and ANSYS CFD-Post R17.0 Academic by building trajectories of the motion of condensed droplets and solid particles in the elbow and T-junction of the linear part of the gas main in the flow of natural gas. The trajectories were painted in colors that match the velocity and diameter of droplets and particles according to the scale of values. After studying the trajectories of discrete phases, the locations of their heavy collision with the pipeline walls were found, as well as the places of turbulence of condensed droplets and solid particles. The velocity of liquid and solid particles was determined, and the impact angles, diameters of condensed droplets and solid particles in the place of collision were found. Such results provide possibilities for a full and comprehensive investigation of erosive wear of the elbow and T-junction of the linear part of the gas main and adjacent sections of the pipeline, and for the assessment of their strength and residual life.

scholarly journals Improving the efficiency of gas pipeline cleaning by controlling the speed of the gas cleaning

2020 ◽  
pp. 29-35
Author(s):  
V. Ya Grudz ◽  
N. B. Slobodian
Keyword(s):  
High Speed ◽  
Moving Boundary ◽  
Linear Part ◽  
Initial Pressure ◽  
Gas Pipeline ◽  
Technological Scheme ◽  
Gas Pipelines ◽  
Technological Parameters ◽  
Degree Of Reduction ◽  
Main Gas Pipeline

An important aspect of improving the hydraulic efficiency of pipeline transport is its periodic cleaning with mechanical cleaning devices. Cleaning gas pipelines with cleaning pistons is a technologically complex process. It is advisable to adjust the speed of the piston to increase the efficiency of cleaning the pipeline with the crossed track profile. On the ascending and plain sections of the route, maintain a high speed of movement of the device, and on the descending it to reduce. To slow down the movement of the piston in the downstream sections of the main gas pipelines, it is proposed to change the technological scheme of the linear part. It is suggested to use a looping connection to change the flow chart. The change of the speed of movement of the treatment device when changing the technological scheme of the main gas pipeline was evaluated. The influence on the dynamics of the movement of the cleaning piston of the main parameters of the pipeline and looping, as well as the parameters of the movement of the piston itself, are investigated. A mathematical model of the process is built, on the basis of the implementation of which the regularities of the treatment device movement when changing the technological scheme of the gas pipeline are established. An equation was obtained to find the ratio of the mass flow rates of gas in the main gas pipeline before and after connecting the loop, which can be solved by the iteration method. The algorithm is developed and the program of calculation of the degree of reduction of the speed of movement of the piston is developed, depending on the kind of technological parameters and technical characteristics of the treatment device and the pipeline. Based on the calculations, the graphical dependences of the relative speed of the piston on the technological parameters and technical characteristics of the main pipeline were constructed. The authors found that the greatest effect on the degree of reduction of the speed of the piston has the length of the loop. It has been investigated that a decrease in the initial pressure and an increase in the final pressure, as well as an increase in the pressure drop at the moving boundary, lead to an improvement in the braking conditions

scholarly journals Problem of conjugate heat transfer between main gas pipeline and frozen ground

2019 ◽  
Vol 102 ◽  
pp. 01001
Author(s):  
Edward Bondarev ◽  
Igor Rozhin ◽  
Kira Argunova
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Conjugate Problem ◽  
Gas Pipeline ◽  
Frozen Ground ◽  
Flow Area ◽  
Tube Cross Section ◽  
Main Gas Pipeline

Mathematical model of non-isothermal gas flow within the framework of tube hydraulics including change of tube cross-section due to hydrate formation and the dependence of coefficient of heat transfer between gas and hydrate layer on varying flow area is proposed. The corresponding conjugate problem of heat exchange between imperfect gas in the pipeline and the environment is reduced to the solution of differential equations describing non-isothermal flow of gas in pipes and heat transfer equations in ground with the corresponding conjugation conditions. In the quasi-stationary mathematical model of hydrate formation (dissociation), the dependence of gas-hydrate transition temperature on gas pressure is taken into account. Some decisions taken in the design of the first section of the main gas pipeline «Power of Siberia» have been analyzed. It has been shown that if gas is not sufficiently dried, outlet pressure may drop below the technological limit in about 6-7 hours. At the same time, for completely dry gas ,it is possible to reduce the cost of thermal insulation of the pipeline at least two fold.

scholarly journals IMPROVING THE EFFICIENCY OF FUNCTIONING OF REPAIR-OPERATING UNITS IN THE SYSTEM OF MAINTENANCE AND REPAIR OF MAGISTRALS

2019 ◽  
pp. 104-115
Author(s):  
V. Y. Grudz ◽  
V. V. Grudz ◽  
V. M. Bodnar ◽  
M. S. Chernetsky
Keyword(s):  
Linear Part ◽  
Gas Pipeline ◽  
Operating Conditions ◽  
Gas Pipelines ◽  
Maintenance And Repair ◽  
Technological Structure ◽  
Optimal Technology ◽  
Main Gas Pipeline ◽  
Operating Units

The classification of failures and damages of the linear part and its separate elements is carried out, variants of technology of carrying out of preventive and repair-restoration works and modular-technological structure of repair and maintenance units are formulated. Particular attention is paid to improving the efficiency of the operation of a separate repair and maintenance unit during maintenance and repair with a known layout scheme and a certain mode of control and restoration works by choosing the optimal technology of work and rational equipment of units and crews leaving for the route. On the basis of the analysis of the technology of work execution it is shown that only a small part of the repair and maintenance measures requires the use of powerful machinery and equipment, which include the first level of priority work on the replacement of gas pipeline sections, work, damage elimination, work on elimination of significant pipeline displacements, work for restoration of soil collapse of the main gas pipeline. In addition, each type of work on the objects of the linear part requires the use of the same vehicles. The type and number of vehicles depend on the particular operating conditions, as well as on the possibility and feasibility of purchasing and operating a particular type of equipment. The method of estimation of indexes of maintenance of linear part of main gas pipelines and efficiency of functioning of repair and maintenance units during maintenance and repair is developed.

scholarly journals Improving the methodology for technical assessment of the linear part of main gas pipelines

2019 ◽  
pp. 102-111
Author(s):  
Aleksandr A. Razboynikov ◽  
Nikolay S. Barsukov
Keyword(s):  
Linear Part ◽  
Technical Condition ◽  
Gas Pipeline ◽  
Gas Pipelines ◽  
Partial Picture ◽  
Technical Assessment ◽  
Main Gas Pipeline

Today evaluation of the technical assessment of the linear part of main gas pipeline is one of the most important tasks of pipeline operation. However, many assessment methodologies provide only a partial picture of the technical condition and don’t take into account the conditions for pipeline laying. This article discusses the improvement of methods for technical assessment of main gas pipelines.

scholarly journals DEVELOPMENT OF METHODS FOR ANALYZING AND ENSURING THE RELIABILITY OF GAS DISTRIBUTION SYSTEMS IN THE TASKS OF INTEGRATED POWER SUPPLY OF LARGE TERRITORIAL FORMATIONS

2021 ◽  
pp. 89-100
Author(s):  
Николай Иванович Илькевич ◽  
Татьяна Владимировна Дзюбина ◽  
Жанна Вадимовна Калинина
Keyword(s):  
Mathematical Model ◽  
Distribution System ◽  
Distribution Systems ◽  
Gas Pipeline ◽  
Reliability Coefficient ◽  
Failure Rates ◽  
Gas Distribution ◽  
Reliability Indicators ◽  
The Impact ◽  
Main Gas Pipeline

Актуальность обусловлена, с одной стороны, необходимостью активной газификации крупных территориальных образований (строящихся новых жилых агломераций, коттеджных и дачных поселков, а также крупных промышленных комплексов). С другой стороны, продолжается увеличение общей протяженности газораспределительных систем и усложнение конфигурации схем газопроводов. Перечисленные факторы влияют на надежность работы газораспределительных систем и предъявляют высокие требования со стороны потребителей энергии к безаварийной их работе. Цель. Основная исходная надежностная информация, используемая для анализа надежности газопроводов, - это интенсивности отказов его элементов: отдельных участков линейной части, газоперекачивающих агрегатов и т.д., и интенсивности восстановления этих элементов. Эти показатели характеризуют такие свойства надежности как, безотказность и ремонтопригодность. Цель исследований заключается в оценке влияния показателей безотказности и ремонтопригодности оборудования на интегральные показатели надежности газораспределительной системы (ГС). К ним относятся математическое ожидание, дисперсия и среднеквадратическое отклонение (с.к.о.) пропускной способности ГС, а также коэффициент надежности газопровода. Методы: эквивалентирования, аналитический метод на уровне случайных Марковских процессов - схема «гибели и размножения», теоремы сложения и умножения вероятностей, композиция рядов распределения; математическая модель анализа надежности проектируемого магистрального газопровода (МГ). Результаты. На основе математической модели оценки надежности проектируемого магистрального газопровода и разработанной вычислительной программы были выполнены расчеты по определению интегральных показателей надежности условной газораспределительной системы. Исследования показали, что при изменении исходных показателей надежности (интенсивностей отказов и восстановлений) элементов ГС на одинаковую величину их влияние на изменение интегральных показателей надежности ГС имеет разную силу. Выводы. На основе предложенной математической модели анализа надежности ГС показано влияние показателей интенсивности отказов и интенсивности восстановлений элементов, характеризующих безотказность и ремонтопригодность газотранспортных систем, на ее интегральные показатели надежности, в частности, на коэффициент надежности. The Relevance of the research is due to the need for active gasification of large territorial entities (new residential agglomerations under construction, cottage and dacha settlements, as well as large industrial complexes). On the other hand, the increase in the total length of gas distribution systems and the complexity of the configuration of gas pipeline schemes continues. These factors affect the reliability of the gas distribution systems and place high demands on the part of energy consumers for trouble-free operation. Purpose. The main initial reliability information used for analyzing the reliability of gas pipelines is the failure rates of its elements: individual sections of the linear part, gas pumping units, etc., and the recovery rates of these elements. These indicators characterize such properties of reliability as reliability and maintainability. The purpose of the research is to assess the impact of reliability and maintainability of equipment on the integral reliability indicators of the gas distribution system (GDS). These include the expectation, variance and standard deviation of the throughput of the GDS, as well as the reliability coefficient of the pipeline. Methods: equivalent methods, analytical method at the level of random Markov processes - the scheme of "death and reproduction", the theorem of addition and multiplication of probabilities, the composition of distribution series; mathematical model of reliability analysis of the designed main gas pipeline. Results. On the basis of a mathematical model for assessing the reliability of the designed main gas pipeline and the developed computational program, calculations were performed to determine the integral indicators of the reliability of the conventional gas distribution system. So, studies have shown that when the initial reliability indicators (failure rates and recoveries) of the GDS elements are changed by the same amount, their effect on the change in the integral reliability indicators of the GDS has a different effect. Conclusion. On the basis of the proposed mathematical model for analyzing the reliability of the GDS, the influence of the failure rate indicators and the recovery rate of elements characterizing the reliability and maintainability of gas transmission systems on its integral reliability indicators, in particular, on the reliability coefficient, is shown.

Study of the mechanical properties of the gas pipeline metal after long-term operation in conditions of the North

2020 ◽  
Vol 86 (6) ◽  
pp. 48-54
Author(s):  
N. I. Golikov ◽  
M. M. Sidorov ◽  
I. I. Sannikov ◽  
A. K. Rodionov
Keyword(s):  
Mechanical Properties ◽  
Residual Strength ◽  
Linear Part ◽  
Full Scale ◽  
Gas Pipeline ◽  
Term Operation ◽  
The North ◽  
Full Scale Tests ◽  
Main Gas Pipeline

The residual strength and technical condition of the material of 530-mm steel pipe (14KhGS) of main gas pipeline are estimated to ensure the safety of long-term operation of pipelines in climatic conditions of the North. The mechanical properties are determined using standard methods of mechanical testing in laboratory conditions. A full-scale pressure test up to failure is used to determine the actual values of the fracture toughness and safety factor of the pipe. Full-scale tests were carried out on a test bench, a computer-measuring complex which displayed the reaction of the object to the load. A pipe fragment was cut from the linear part of the main gas pipeline and welded with spherical plugs. The outer surface of the pipe was notched along the pipe axis. The depth of the notch was calculated such that the breaking load on the ligament section at the notch site corresponded to the working pressure of the gas pipeline. No significant changes in the mechanical properties of the pipe metal were revealed in the absence of visible corrosion and deformation damage during long-term operation of the pipe in the North. Impact tests did not reveal embrittlement of the metal of the tested pipes. Full-scale tests of a pipe with an artificially applied defect made it possible to calculate the value of the critical stress intensity factor, which allowed us to estimate the residual strength of a pipe with a longitudinal crack. The value of the strength criterion of the fracture mechanics indicates the preservation of a sufficiently high viscosity of sheet metal pipes. Similar tests of the pipes (of other size and made of other materials) operating in the main gas pipelines should be continued taking into account temperature ranges and material degradation after long-term operation.

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