scholarly journals Influence of the length parameter of an underground oil pipeline on the frequency of free oscillation

2020 ◽  
Vol 164 ◽  
pp. 03024
Author(s):  
Sokolov Vladimir ◽  
Igor` Razov ◽  
Andrey Dmitriev
Keyword(s):  
Large Diameter ◽  
Longitudinal Direction ◽  
Soil Conditions ◽  
Attached Mass ◽  
Natural Oscillations ◽  
Oil Pipeline ◽  
Elastic Resistance ◽  
Oil Pipelines ◽  
Modes Of Vibration ◽  
Thin Walled

The problem of finding the natural frequencies of thin-walled underground oil pipelines is solved, based on the application of a semi-momentless theory of cylindrical shells of medium bending, in which bending moments in the longitudinal direction are not taken into account in view of their smallness compared with moments acting in the transverse direction. The solution to this approach is a fourth-order homogeneous differential equation satisfying the boundary conditions of articulation at each end. This equation includes the parameters of the length, internal pressure, thinness of the pipeline, as well as the values of the coefficient of elastic resistance of the soil, the attached mass of the soil and the attached mass of the flowing oil. Based on the data obtained by the derived formulas, the frequency characteristics of large-diameter thin-walled underground oil pipelines are determined depending on the length of the element, as well as on the soil conditions. It has been established that the minimum frequencies are realized for shell modes of vibration with a length parameter of the pipeline section (the ratio of the length of the section to the radius) not exceeding 13. A formula is derived that allows one to determine the boundary between the use of the rod and shell theory for calculating pipelines for dynamic effects. Using the dynamic stability criterion, in which the frequency of natural oscillations vanishes, expressions are derived that allow one to determine the external critical pressure on the wall of the pipeline, which takes into account the length of the pipeline, as well as the number of half waves in the transverse and longitudinal directions, in which the pipeline goes into emergency condition.

scholarly journals Investigation of the frequency of free vibrations for pipelines with different physical and mechanical properties of the material

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Andrey Dmitriev
Keyword(s):  
Mechanical Properties ◽  
Large Diameter ◽  
Physical And Mechanical Properties ◽  
External Pressure ◽  
Pipe Length ◽  
Shell Form ◽  
Underground Pipelines ◽  
Elastic Resistance ◽  
Ground Conditions ◽  
Thin Walled

This paper raises the question of a new approach to the dynamic calculation of thin-walled underground pipelines of large diameter, which is based on the application of the Vlasov-Novozhilov half-time theory of medium-bend shells, which ignores the M1 moments that bend the cylindrical shell in the longitudinal direction, since they are much smaller than the M2 moments that bend it in the transverse direction. The resolving equation for this approach is a homogeneous 4th-order differential equation that uses two boundary conditions at each end to solve it. The resulting equation takes into account the parameter of the longitudinal force, the value of the internal pressure, the coefficient of elastic resistance of the soil, the parameter of thinness, as well as the attached mass of the soil. Based on the data obtained from the derived formulas, the frequency characteristics of thin-walled underground pipelines of large diameter with different physical and mechanical properties are determined depending on the length of the element, as well as ground conditions. It is established that the minimum frequencies for the shell form of vibrations in various ground conditions are realized only for steel pipes, and for polyethylene and fiberglass pipes, depending on the coefficient of elastic resistance of the soil, they can be realized both in the rod and shell form. At the same time, using a dynamic stability criterion, derived expressions to determine the critical external pressure, taking into account the pipe length and the number of half waves in the cross section in which there is a constructive denial of the pipeline. Based on this expression, a formula for determining the critical depth of laying for thin-walled pipelines is obtained.

scholarly journals Frequency Converter for Induction Heating Oil in Oil Pipelines

2021 ◽  
Vol 12 ◽  
pp. 24-31
Author(s):  
N. Т. Isembergenov ◽  
A. J. Sagyndikova ◽  
M. Zh. Konyrova
Keyword(s):  
Induction Heating ◽  
High Frequency ◽  
Eddy Currents ◽  
Frequency Converter ◽  
Large Diameter ◽  
Electrical Energy ◽  
Oil Pipeline ◽  
Oil Pipelines ◽  
Heating Oil ◽  
Frequency Current

Heating oil in oil pipelines to the required temperature, with the most efficient use of electrical energy,is possible with using of the induction heating method. The most important parameter of induction heating settings is frequency. For each process, there is an optimal frequency range that provides the best technological and economic results. Induction heating of the oil pipeline occurs as follows, if alternating high-frequency current is passed through the windings of the oil pipeline inductor (Fig. 1), an alternating magnetic field is formed, which intersects the metal walls of the oil pipeline and induces eddy currents in them. These currents heat the metal walls of the pipeline to the desired temperature and, accordingly, the oil. MITSUBISHI's VIPM Series Intelligent Power Transistor Modules (IPM), which is a functionally complete product, are currently developed and marketed. These transistor modules are designed for high voltages, currents and power. A frequency converter made on these transistor modules allows to heat large diameter oil pipelines. A prototype IGBT transformer was designed and manufactured. Figure 2 shows a prototype of a frequency converter with a power of 6 kW at frequencies from 2 to 20 kHz. Induction heating of metal was used as a load for the frequency converter

Using clusterization principles for the selection of repair sections of main oil pipelines based on diagnostic data

2011 ◽  
Vol 8 (1) ◽  
pp. 201-210
Author(s):  
R.M. Bogdanov
Keyword(s):  
Cluster Analysis ◽  
Defect Density ◽  
Density Variation ◽  
Distance Functions ◽  
Oil Pipeline ◽  
Oil Pipelines ◽  
Classification Of Images ◽  
Main Oil Pipeline ◽  
Selection Of

The problem of determining the repair sections of the main oil pipeline is solved, basing on the classification of images using distance functions and the clustering principle, The criteria characterizing the cluster are determined by certain given values, based on a comparison with which the defect is assigned to a given cluster, procedures for the redistribution of defects in cluster zones are provided, and the cluster zones parameters are being changed. Calculations are demonstrating the range of defect density variation depending on pipeline sections and the universal capabilities of linear objects configuration with arbitrary density, provided by cluster analysis.

Modified equations for hydraulic calculation of thermally insulated oil pipelines for the case of a power-law fluid

2021 ◽  
pp. 388-395
Author(s):  
Марат Замирович Ямилев ◽  
Азат Маратович Масагутов ◽  
Александр Константинович Николаев ◽  
Владимир Викторович Пшенин ◽  
Наталья Алексеевна Зарипова ◽  
...  
Keyword(s):  
Power Law ◽  
Analytical Calculation ◽  
High Viscosity ◽  
Hydraulic Calculation ◽  
Flow Index ◽  
Pipeline System ◽  
Power Law Fluid ◽  
Simplified Approach ◽  
Oil Pipeline ◽  
Oil Pipelines

Теплогидравлический расчет неизотермических трубопроводов является наиболее важным гидравлическим расчетом в рамках решения задач обеспечения надежности и безопасности работы нефтепроводной системы. Для практических расчетов применяются формулы Дарси - Вейсбаха и Лейбензона. При этом в ряде случаев (короткие теплоизолированные участки, поверхностный обогрев нефтепроводов) можно использовать упрощенный подход к расчету, пренебрегая изменением температуры или учитывая температурные поправки. В настоящее время формулы для аналитического расчета движения высоковязких нефтей в форме уравнения Лейбензона получены только для ньютоновской и вязкопластичной жидкостей. Для степенной жидкости соответствующие зависимости отсутствуют, расчет ведется с использованием формулы Дарси - Вейсбаха. Целью настоящей статьи является представление формулы Дарси - Вейсбаха для изотермических течений степенной жидкости в форме уравнения Лейбензона. Данное представление позволит упростить процедуру проведения аналитических выкладок. В результате получены модифицированные уравнения Лейбензона для определения потери напора на участке нефтепровода в диапазоне индекса течения от 0,5 до 1,25. В указанном диапазоне относительное отклонение от результатов расчетов с использованием классических формул Метцнера - Рида и Ирвина не превышает 2 %. The thermal-hydraulic calculation of non-isothermal pipelines is the most important hydraulic calculation in the framework of solving the problems of ensuring the reliability and safety of the oil pipeline system. For practical calculations, the Darcy - Weisbach and Leibenson formulas are used. Moreover, in a number of cases (short heat-insulated sections, surface heating of oil pipelines), a simplified approach to the calculation can be used, neglecting temperature changes or taking into account temperature corrections. At present, formulas for the analytical calculation of the motion of high-viscosity oils in the form of the Leibenson equation have been obtained only for Newtonian and viscoplastic fluids. For a power-law fluid, there are no corresponding dependences; the calculation is carried out using the Darcy - Weisbach formula. The purpose of this article is to present the Darcy - Weisbach formula for isothermal flows of a power-law fluid in the Leibenzon form, which will simplify the procedure for performing analytical calculations. The modified Leibenzon equations are obtained to determine the head loss in the oil pipeline section in the range of the flow index from 0.5 to 1.25. In the specified range, the relative deviation from the results of calculations using the classical Metzner - Reed and Irwin formulas does not exceed 2 %.

The Development of Large Diameter and Thickness X80 HSAW Linepipe

2008 ◽  
Author(s):  
Weiwei Li ◽  
Chunyong Huo ◽  
Qiurong Ma ◽  
Yaorong Feng
Keyword(s):  
Bauschinger Effect ◽  
Pipeline Steel ◽  
Large Diameter ◽  
Base Material ◽  
Longitudinal Direction ◽  
Strength Loss ◽  
Ring Test ◽  
Low Carbon ◽  
Pipeline Project ◽  
Submerged Arc

For the requirement of 2nd West-East Pipeline Project of China, X80 large diameter & thickness linepipe with helical seam submerged arc welded (HSAW) were developed, with 1219 mm OD and 18.4 mm WT. Acicular ferrite type and super-low carbon, high Niobium chemical composition pipeline steel was adopted for the base material. The very stringent requirements at −10 °C for toughness, i.e. 220J/170J for average/minimum for pipe body and 80J/60J for average/minimum for weld and HAZ were meet successfully. The yield strength loss due to Bauschinger effect was found lower than 20MPa, which benefited. The very low residual stress level was testified by cut-ring test which cuts a section pipe about exceed 100mm long, and then cut the section apart from welds 100mm along the longitudinal direction.

scholarly journals Study on Optimizing Operation of Preheating Commissioning for Waxy Crude Oil Pipelines

2014 ◽  
Vol 6 ◽  
pp. 894256
Author(s):  
Jian Zhang ◽  
Yi Wang ◽  
Xinran Wang ◽  
Handu Dong ◽  
Jinping Huang ◽  
...  
Keyword(s):  
Crude Oil ◽  
Outlet Temperature ◽  
Fluid Temperature ◽  
Governing Equations ◽  
Waxy Crude Oil ◽  
Waxy Crude ◽  
Oil Pipeline ◽  
Single Station ◽  
Oil Pipelines ◽  
Volume Method

A mathematical model is established for the preheating commissioning process of waxy crude oil pipelines. The governing equations are solved by the finite volume method and the finite difference method. Accordingly, numerical computations are made for the Niger crude oil pipeline and the Daqing-Tieling 3rd pipeline. The computational results agree well with the field test data. On this basis, fluid temperature in the process of the preheating commissioning is studied for single station-to-station pipeline. By comparing different preheating modes, it is found that the effect of forward preheating is the best. Under different preheating commissioning conditions, the optimal combination of outlet temperature and flow rate is given.

scholarly journals Evaluation of stresses in large diameter, thin walled piping at support locations

1992 ◽  
Author(s):  
B.J. Bryan ◽  
H.E. Jr. Flanders ◽  
G.B. Jr. Rawls
Keyword(s):  
Large Diameter ◽  
Thin Walled

scholarly journals Free oscillations of thin-walled bimetallic pipelines of large diameter on an elastic foundation

2018 ◽  
Vol 193 ◽  
pp. 02027
Author(s):  
Vladimir Sokolov ◽  
Igor Razov ◽  
Evgeniy Koynov
Keyword(s):  
Elastic Foundation ◽  
Nuclear Power ◽  
Large Diameter ◽  
Compressive Force ◽  
Free Oscillations ◽  
Working Pressure ◽  
Momentum Theory ◽  
Internal Working ◽  
Nonlinear Version ◽  
Thin Walled

In the article, solutions are obtained for a thin-walled bimetallic pipeline. Solutions are obtained, and the frequencies of free oscillations are investigated taking into account the internal working pressure, the longitudinal compressive force, and the elastic foundation. The solutions were obtained on the basis of a geometrically nonlinear version of the semi-momentum theory of cylindrical shells of the middle bend. The proposed calculations can find application in the nuclear power industry, aviation, and the petrochemical industry.

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