Oil Pipe Research Articles

GA-based fuzzy logic control of a solar power plant using distributed collector fields

A novel genetic algorithm (GA) based fuzzy logic control (FLC) system has been developed for the solar power plant, Plataforma Solar de Almería (PSA) at Tabernas, in Almería, Spain. The rule base encompasses an empirical set of 49 “ if-then” rules. Chromosomes consisting of 49 genes of 5-bit data are created to link to the rule base. The 5-bit data of each gene represents the stength of the corresponding ‘If-Then’ rule. The GA performs the basic operations of reproduction, crossover and mutation on a pool of chromosomes to search for the best rule base which optimises the response time of the plant to input temperature or power demand by controlling the distributed collector field of the plant. The collect field is essentially an array of parabolic mirrors and oil pipes in which the transversal of solar energy takes place. Simulation results on the plant with an optimised rule-base using the 100th generation of the chromosome show that the proposed GA-FLC scheme gives a better and more robust performance of the plant than other schemes previously implemented.

Thermal characteristics of a class F fly ash

It is necessary to evaluate thermal properties of geotechnical materials, viz. soils and rocks, for power cables and oil pipe lines and disposal of nuclear wastes. A situation may arise where the heat dissipation through the soils and rocks may not be satisfactory, leading to adoption of a backfill. Fly ash can be used in conjuction with aggregates to design a proper backfill material. The thermal characteristics of this material, in terms of its resistivity, play an important role in the design of a thermally stable backfill, i.e., Fluidized Thermal Backfill (FTB). As such it is desired to establish thermal response of the fly ash based on its physical and moisture- holding characteristics. In this paper an effort has been made to evaluate the thermal resistivity of a Class F fly ash using a laboratory thermal needle/probe. The effect of density of compaction and the moisture content on the thermal response of the fly ash has been also studied.

Three-dimensional thermomechanical analysis of circumferentially welded thin-walled pipes

Circumferentially welded pipes are frequently used in boiling water reactor piping systems, oil pipe transport systems and steam piping systems. When two pieces of pipe are welded together, residual stresses arise in the vicinity of the weld owing to the circumferential welding of the pipes. Residual stresses are attributed to the elastoplastic response of the object towards the transient thermal stresses generated by the thermal cycle. They can be a major source of cracking and fracture problems in welded structures. Finite element simulation of the welding process is a highly effective means of predicting thermomechanical behavior. To enhance the accuracy of the numerical solution and bring it close to the real situation, this work presents a three-dimensional finite element model. The three-dimensional temperature and stresses in circumferential single-pass welded pipes are also analyzed using the elastic–plastic three-dimensional finite element method. Exactly how the pipe wall thickness influences the welding residual stresses is also discussed.

Diagnostic Technologies Using Optical Fibers.

This article describes diagnostic technologies using optical fibers for large scale constructions and life-lines in the civil engineering field. Because of their low transmission loss, fiber sensing technologies are highly effective for monitoring a series of long objective, such as gas and oil pipe lines or power and communication cable lines. In addition, the Optical Time Domain Reflectometry (OTDR) method and the newly developed fiber devices of Fiber Bragg Grating and Fiber Fabry-Perot interferometer provide us many applications for diagnostic requirements.

A study of residual stresses in multi-pass girth-butt welded pipes

Girth-butt welds in pipes have been widely employed in diverse applications, such as boiling water reactor piping systems, oil pipe transport systems and steam piping systems. Owing to localized heating by the welding process and subsequent rapid cooling, residual stresses can arise in the inner surfaces of the girth welded pipes. The association of residual stresses with intergranular stress corrosion cracking poses significant problems in the accurate fabrication of pipes. In this work we predict the residual stresses during multi-pass are welding in steel pipes using finite element techniques. The effects of pipe diameter and wall thickness on weld residual stresses are also discussed.

Fundamental characteristics of wear particle deposition measurement by an improved on-line ferrographic analyzer

An improved on-line ferrographic analyzer and its specific characteristics are presented. This analyzer is very convenient for detecting wear debris in a transparent oil pipe of a machine by using an electromagnet and a photoelectric sensor with a microprocessor. To eliminate the detection error of background colour of the oil sample, the wear index is redefined and can be directly calculated by the microprocessor in this analyzer. This detected value can represent the covered area rate of deposited wear debris and is able to present accurately the debris concentration. Results show that the wear index is slightly decreased by higher viscosity, and that the effects of a flow rate of the oil sample lower than 2 ml min −1 on the wear index are not obvious. A simple theory, accounting for the balance between the magnetic and fluid drag forces on the wear particles, is presented and shows very good agreement with experimental results.

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes : Golovinskii, A.G.; Kiselev, A.V.; Kotkis, A.M.; Khokhlov, N.F.: Shiryaev, A.M. Soviet Journal of Nondestructive Testing, Vol. 26, No. 8, pp. 540–544 (Apr. 1991)

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes : Golovinskii, A.G.; Kiselev, A.V.; Kotkis, A.M.; Khokhlov, N.F.: Shiryaev, A.M. Soviet Journal of Nondestructive Testing, Vol. 26, No. 8, pp. 540–544 (Apr. 1991)

Investigation into in-place cleaning of dry gas seals

Tandem dry seals installed in centrifugal pipeline compressors are susceptible to contamination from the process gas and from the lube oil system during upset conditions. Contamination found within a dry seal can include lube oil grease, condensate, glycol, pipe scale and desiccant. Over time, contamination can collect to a degree which influences the performance of the dry seal. The deterioration in performance is characterized by erratic first stage seal leakage during operation, or during a start up. To restore performance, it is typically necessary to remove the seal, refurbish and replace internal seal components.

Melting Solid Plug Between Two Coaxial Pipes by a Moving Heat Source in the Inner Pipe

Melting of a solid plug in the gap between two coaxial pipes by inserting a moving heat source in the inner pipe is investigated. Using a scale analysis, closed-form solutions for temperatures of liquid in the inner pipe, solid plug and liquid in the annular gap, and the surrounding medium around the outer pipe are determined. It is shown that eight independent dimensionless parameters are required to specify the entire process. The effects of independent parameters on the shapes of the molten region in the gap are found. The analysis and results provided are useful for the design of oil pipes.

Mobile robots on cylindrical surfaces

This paper proposes some basic structures of mobile robots which can run on cylindrical surfaces. This type of robot is utilized to inspect such cylindrical components as oil pipe lines, electricl ...

Introduction of the production of hydrogen sulfide-resistant oil and gas pipe of 12GF steel at Volga Pipe Plant

1. A method has been developed and experimental lots have been produced of petroleum and gas pipe resistant to hydrogen sulfide cracking and corresponding to strength category II of TU 14-3-1619-89 (type X42 of API Specification 5L-85). 2. The hydrogen sulfide cracking threshold stress of 12GF steel pipe after heat treatment is not less than 0.8 of the minimum specified yield strength.

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes

Acoustic emission from fatigue cracks in oil pipe welds

Acoustic emission from fatigue cracks in oil pipe welds

The life of glass-reinforced plastic oil pipes

The life of glass-reinforced plastic oil pipes

Nondestructive testing of large-diameter pipe for oil and gas transmission lines

Nondestructive testing of large-diameter pipe for oil and gas transmission lines

Developments in geothermal energy in Mexico—part twenty-five: Operating experience with a geothermal wellhead turbine

After several months of operation of a wellhead 5 MW geothermal turbine, an incident occurred due to the failure of the governor oil pipe joint. The oil tank drained out causing damage to the turbine bearings. Heavy scaling of the first blading stage of the turbine was observed, particularly in the nozzles. Recommendations for the design and remote control operation of the wellhead unit are discussed with reference to the faults found in this case.

The effects of the diameter of an oil feeding pipe on the discharge characteristics of a fluidic diodes oil pump.

In this paper, we investigated the effects of the resistance of an oil feeding pipe on the discharge characteristics of an oil pump for a horizontal type compressor. This pump uses fluidic diodes in place of conventional valves. The discharge characteristics of this pump depend on the resistance balance between the discharge line and the suction line. The resistance of the oil pipe is as remarkable as that of fluidic diodes. This resistance is composed of not only friction and velocity head, but also the inertia of the oil in it. The effect of the resistance becomes larger as the diameter of this pipe decreases. So we analyzed the resistance of each section of this pump and calculated the change of the flow rate under various pipe diameters. As a result of this study, we have found that the optimum diameter of the pipe gives us the greatest discharge of the oil feeder pump.

Characteristics of streaming electrification in pressboard pipe and the influence of an external electric field

Fundamental studies on electrification phenomena of transformer oil and cylindrical pressboard pipes were carried out. Formulae are obtained from a simple theory based on the separation and relaxation of charges. The formulae agree with experimental data of leakage current from the pipes and explain the dependence on flow velocity, electrical conductivity and temperature of oil in both laminar and turbulent flow. The effect of surface roughness of the duct on streaming electrification is investigated by preparing spiral protuberances with different heights on the inner surface of each pipe. The streaming electrification is enhanced by an external electric field. The effect is sensitive to the applied voltage, its frequency and oil temperature. The theoretical formulae obtained in this paper explain these phenomena very well.

Prediction of flux distribution as a means to nondestructive testing of oil-pipe materials (abstract)

The flux distribution for a given excitation is determined in the cross section of an oil pipe, in its interior and exterior regions, in order to utilize this information eventually for the nondestructive testing of the material of the pipe. A two-dimensional mathematical model is established under certain simplifying assumptions and the grid system is laid out for numerical analysis. The relevant partial differential equations of the magnetic vector potential as well as their difference algorithms are developed. An innovative combination of rectangular and polar grid systems is used to follow the contours of the cross section consisting of the oil pipe and the excitation mechanism made up of a core, coil, and two steel brushes. The reluctivity of ferromagnetic materials is assumed to be a function of the magnetic induction. An iterative procedure consisting of successive-point relaxation of vector potentials with an optimum over-relaxation factor, a block-relaxation method for accelerating the convergence, relaxation of reluctivities with an optimum under-relaxation factor, and a constant monitoring of the convergence of the sum of absolute values of residuals as well as of the absolute value of the maximum residual is described. Computer programs in fortran language are developed and applied to find the flux distribution inside and outside the cross section of the oil pipe for various excitation-current densities. Analytical results are compared with experimental data. Refined analyses including eddy-current and three-dimensional effects are under way.

特性格子法に基づく流体管路の過渡応答の解析

An approach is made for the analyses of the transient responses of pneumatic and oil pipe lines. The algorithm based on the characteristics grid method considers the variations of the density, pulse wave speed and kinematic viscosity of the fluids due to the pressure changes in pipes. The numerical results are compared with the experimental results or the ones ob t ained by other analyticalm ethods for problems of this type and discussed to obtain the following conclusions: The approach is effective in predicting the transient responses of pneumatic pipe line. And also, in oil pipe lines, it obtains excellent results inclusive of the severe pressure changes due to high-pressureo peration of the directional control valve.