Small Diameter Pipes Research Articles

Noncontact Magnetostrictive Torsional Guided Wave Sensors for Small-Diameter Pipes

The magnetostrictive torsional wave sensors are focused on magnetostrictive patch transducer. These transducers use a material with a high magnetostrictive coefficient on the pipe surface to increase the excitation efficiency for detection. However, this approach loses the noncontact characteristic of the magnetostrictive guided waves. To enable noncontact detection in small-diameter pipes using torsional waves, a magnetostrictive torsional wave sensor with a tile-shaped magnet is designed in this article. By optimizing the structure of the static magnetic field, the circumferential magnetic field of the pipe is enhanced. The amplitude and the signal-to-noise ratio of the guided waves are also improved. The tile-shaped magnet with shoving magnetic structure is used to realize a uniform circumferential magnetic field. A solenoid coil is used to provide the axial dynamic magnetic field to generate the torsional waves that are used to detect the pipes. In this article, the principles of torsional wave sensors are studied first. The static magnetic field results for different structures are then analyzed via simulations. Finally, experiments show that the magnetostrictive torsional wave sensors with the tile-shaped magnets can realize the excitation and detection of torsional waves in pipes, which can be used to detect the locations and sizes of defects in these pipes.

Чувствительность электромагнитно-акустического метода многократной тени с использованием рэлеевских волн при контроле труб нефтяного сортамента

The paper proposes algorithms for signals processing obtained by the multiple shadow method using Rayleigh waves propagating in the direction of the envelope pipe, and an electromagnetic-acoustic method of emission-reception. The results of a study of the sensitivity of the method to artificial and natural surface and near-surface defects of workpieces of drill pipes in two frequency ranges are presented. As informative parameters, it is proposed to use the multiple coefficient of detectability, as well as the probabilistic characteristics of dispersion, asymmetry and kurtosis in the analysis of a series of multiple passes, and the criteria for rejection are substantiated. The research results can be used in the development of automated installations and methods for monitoring pipes of small diameter.

Sensitivity of Electromagnetic-Acoustic Multiple Shadow Method Using Rayleigh Waves in Inspection of Oil Country Tubular Goods

We propose algorithms for processing signals obtained by the multiple shadow method using Rayleigh waves propagating in the direction of the pipe envelope and electromagnetic-acoustic emission-reception technique. The results of studying the method susceptibility to artificial and natural surface and near-surface defects of workpieces intended for the production of drill pipes in two-frequency ranges are presented. The multiple detection coefficient and the probabilistic characteristics of variance, asymmetry, and kurtosis are proposed to be used as informative parameters in analyzing the series of multiple signal passes. The rejection criteria are substantiated. The research results can be used in the development of automated units and methods for monitoring small-diameter pipes.

Characterization of a Partially Covered AM-MPT and Its Application to Damage Scans of Small Diameter Pipes Based on Analysis of the Beam Directivity of the MHz Lamb Wave.

To perform a complete scan of a small diameter pipe is difficult for two reasons. First, the beam directivity of the Lamb wave within a small diameter pipe is worse than that within a large diameter pipe. Second, the circumferential range of the small diameter pipe is so limited that it can allow less transducer to be attached on its surface. That means the signals from various circumferential positions are difficult to obtain. This article reports a method that can scan damage within a small diameter pipe using a partially covered axially magnetized magnetostrictive patch transducer (AM-MPT) around the circumference of a pipe based on the analysis of the beam directivity of the MHz Lamb wave. The partially covered AM-MPT was moved around the circumference of a pipe for subsequent measurements to get signals from various circumferential positions. To trigger strong enough MHz Lamb wave, the circumferential coverage of the partially covered AM-MPT was not less than half of the circumference of the pipe, and the greater length-to-width ratio of the magnetostrictive patch was used. The analytical model of beam directivity of the Lamb wave was used to study the Lamb wave propagation in the rolled plate. Then the analytical model was modulated to evaluate the damage scan within a small diameter pipe. The experimental results supported the analytical model through different circumferential coverages of the transducer, and different sizes and axial positions of the damage. The proposed method was proven to have the potential to be applied to damage scans within a small diameter pipe.

Movement Control for an Omnidirectional Mobile Mechanism for Pipe-Inspection Robot in Small Diameter Pipes

Movement Control for an Omnidirectional Mobile Mechanism for Pipe-Inspection Robot in Small Diameter Pipes

Development of Effective Roll-Pass Designs for Production of Longitudinally Welded Pipes of Small and Medium Diameters

Development of Effective Roll-Pass Designs for Production of Longitudinally Welded Pipes of Small and Medium Diameters

Experimental and simulated optimization study on dynamic heat discharge performance of multi-units water tank with PCM

The water tank is most commonly a crucial energy storage device of a solar heating system. However, few existing studies have focused on the quantitative analysis of the heat discharge process of a square water tank. In this paper, a multi-units water tank with phase change material (MWT-PCM) was proposed. The dynamic heat discharge performances of the MWT-PCM and the conventional water tank both with 235.8 dm 3 were compared experimentally. A validated mathematical model was established to optimize the configuration of the MWT-PCM. Results demonstrated that: (1) The water temperature of both tanks had a sharp decline at the initial stage of the heat discharge process. (2) The instantaneous residual effective heat and the instantaneous heat supply of the WMT-PCM were 127% and 45.6% higher than that of the conventional water tank on average, respectively. (3) Due to the PCM, the effective heat discharge time could be prolonged by about 90 min. (4) When the PCM was arranged in a multi-unit manner, a small flow rate operation was recommended. However, the effect of changes in the total mass of the PCM was not obvious, and thus, for the given total mass, a smaller pipe diameter was recommended.

The Numerical Investigation on the Relationship Between Hydrodynamic and Mass Transfer Gas Liquid of Dimutriscu-Taylor Bubble in a Small Diameter Pipe. Experimental Validation

The Numerical Investigation on the Relationship Between Hydrodynamic and Mass Transfer Gas Liquid of Dimutriscu-Taylor Bubble in a Small Diameter Pipe. Experimental Validation

Special aspects of the process of welding fixed joints between thin-walled heat pipes made of aluminum alloys for the ISS modules

The process of joining thin-walled small-diameter pipes made of aluminum alloys using welding has some special aspects to it. Volumetric analysis shows occurrence of welding defects in the form of cracks, pores and oxide inclusions that are inadmissible according to the requirements of technical standards. This paper discusses a process for welding heat pipes to be used in rocket and space hardware, as well as presents solutions for scientific and technological problems encountered in the course of their making, such as: • Methods of preparing parts for welding and the process of welding composite members of heat pipe structure made of aluminum alloys with the use of special tooling; • An illustrative example of using effective creative assembly of pipes for welding with the use of a coolant which provides additional removal of heat from the area of the welded joint; • A well-chosen automated mode of welding fixed joints between thin-walled pipes using modern main and auxiliary welding materials and an inert protective gas that has a high degree of purification owing to a reduction of its contaminants content and its storage in bottles of an advanced design; • Use of a welding wire made to special specifications and stored in specialized vacuumed bags made of polyethylene film; • An analysis of possible methods of welding heat pipes and development of the best process for their welding that takes into account the physical, chemical and mechanical properties of the material and special operational aspects of structure. Key words: sealing of heat pipes, fixed joints between pipes, aluminum alloys, thin-walled small-diameter pipes

Effects of saturation temperature on the boiling properties of carbon dioxide in small diameter pipes at low vapour quality: Pressure drop

The thermal management of most of the silicon pixel detectors at the heart of the Large Hadron Collider experiments at CERN relies on boiling carbon dioxide inside compact heat exchangers of small hydraulic diameter at saturation temperatures between +15 ∘C and −30 ∘C. Due to the current lack of suitable predictive models, a long-term study has been launched to create a consistent and reliable experimental database studying the peculiarities of boiling carbon dioxide in mini- and micro-channels. This study presents results on the total pressure drop of boiling carbon dioxide at low vapour quality (0 < x < 0.4) in 200 mm-long stainless steel tubes with an inner diameter of 2.15 mm, 1 mm and 0.5 mm. By means of a dedicated test setup equipped with high precision sensors, a wide range of saturation temperatures (+15 ∘C to −25 ∘C) and mass fluxes (100 to 1800 kg/m2s) have been explored and diabatic tests were carried out for heat fluxes from 5 to 35 kW/m2. The data presented focus on the influence of the saturation temperature on the two-phase pressure drop. It is suggested that the combination of shifting physical properties of carbon dioxide and different confinement conditions causes a change in the phenomenological behaviour of the flow and that a transition between macro- and micro-scale most likely occurs within the range of test parameters. It is further shown that a shift in the applicability of existing prediction methods is caused by those effects and no correlation is able to predict the experimental data and trends in the whole temperature range. A selective approach to the use of existing correlations is also proposed.

Ertical Butt Welding Technology of Q355g Small Diameter Pipe TIG

In this paper, according to the requirements of welder's technical qualification specification, combined with the practice training topic of TIG vertical butt welding, we have repeatedly trained the operation process of TIG vertical butt welding of q355g steel pipe with specification of Φ 60 х 5,And we adopt the following process measures in the welding process: before welding, we make V-shaped tooling by combining with the workpiece ; when welding, we choose reasonable process parameters; at the same time, we pay more attention to the welding operation skills of backing and cover layer. Therefore, we have achieved satisfactory weld quality, and the relevant experience has been popularized in the teaching process of the school to obtain good evaluation.

Water Holdup Measurement of Gas-Liquid Flows Using Distributed Differential Pressure Sensors

In order to reduce the measurement error caused by non-uniform distribution of dispersed phase, distributed differential pressure sensors are used to measure the pressure drop of gas-liquid flows in small diameter pipe. Water holdup in vertical upward pipe is predicted by the distributed differential pressure sensors, based on the correlations of mixture friction coefficient ${f}_{\textit {tp}}$ under different flow patterns. The water holdup measured by the rotating electric field conductivity sensor is used as the reference value based on the improved Maxwell equations. The dynamic experiments prove that the water holdup prediction accuracy of Ansari model is higher than that of Zhang model, and it can achieve a satisfactory prediction result for water holdup of gas-liquid two-phase flow in small diameter pipe. The average absolute deviation (AAD) of the predicted water holdup relative to the reference water holdup is 0.026, and the average absolute percentage deviation (AAPD) is 5.52%.

Comparison of Technologies for Condition Assessment of Small-Diameter Ductile Iron Water Pipes

AbstractAmong the various diameter classes of ductile iron pipe (DIP) used in water distribution systems, small-diameter pipes [i.e., pipes with a diameter less than or equal to 305 mm (12 in.)] re...

Application of Adaptive Cubature Kalman Filter to In-Pipe Survey System for 3D Small-Diameter Pipeline Mapping

A modified cubature Kalman filter (CKF) algorithm is proposed for an in-pipe survey system. This survey system can provide accurate three-dimensional (3D) location information for underground pipelines without external auxiliary location measurements. To move through a small-diameter pipe, the large size of the tactical grade inertial sensor is replaced with a low-cost micro-electromechanical system (MEMS) inertial measurement unit (IMU). Because the decrease in sensor accuracy increases the positioning error, it is necessary to improve the original filtering algorithm. The following improvements were made in relation to previous studies: geomagnetic and gravity sensors were introduced to obtain the observed vectors of the filter. The CKF was used to solve the nonlinearity of the filter's attitude errors. Furthermore, the CKF process noise matrix can be adaptively adjusted using the raw gyroscope measurements (ACKF) to maintain filter stability. Finally, the experimental results for the extended Kalman filter (EKF), unscented Kalman filter (UKF), CKF, and ACKF were compared to verify the effectiveness of ACKF.

Methodology for circumferential localisation of defects within small-diameter concrete-covered pipes based on changing of energy distribution of non-axisymmetric guided waves

Concrete causes substantial attenuation on ultrasonic guided waves during their propagation within a pipe. The circumferential position of the defect is even more difficult to detect in a concrete-covered pipe with a small diameter. This paper reports that the axial and circumferential positions of a circumference defect in a small-diameter concrete-covered pipe can be identified by moving the half-covered axial magnetised magnetostrictive patch transducer (AM-MPT) around the circumference of the pipe for subsequent measurements. First, the theory of normal mode expansion (NME) and demagnetisation is presented for the proposal of the nondestructive test (NDT) method and half-covered AM-MPT. Second, the NDT method based on NME is explained. Subsequently, the finite element models and experiments are applied to reveal the propagation of triggered and reflected non-axisymmetric guided waves L(M,2) to prove that the proposed method is applicable. Third, several frequencies of L(M,2) are compared to determine the best fit. The experimental results of pipes tested using half-covered AM-MPTs with different length–width ratios of iron cobalt patches proved that the greater the length–width ratio, the greater the amplitude of L(M,2) signals. These results support the theoretical results for the demagnetising field. The signals received from different circumferential positions of the pipe using AM-MPTs reveal that increasing the coverage of the transducer can improve the consistency of the signals received from the different circumferential positions. Next, the group velocity and attenuation characteristics of L(M,2) within the concrete-covered pipes were studied through experiments, with results matching the theoretical results. Finally, the experimental results proved that the proposed method could be utilised to determine the axial and circumferential positions of the defect in concrete-covered pipes. Moreover, the precision of the detection results can be improved by adding the monitoring position around the circumference of the pipe. It was demonstrated that the proposed method has potential to detect defects in concrete-covered pipes.

Performance comparison of a vertical direct expansion geothermal evaporator: PART II, multiple U-pipes

Part I showed that Carbon Dioxide (CO2) is a promising candidate for use in vertical direct expansion ground evaporators, as it requires smaller pipe diameters within the geothermal heat exchanger and lower power for refrigerant circulation compared to conventional refrigerants. Furthermore, pressure change along the geothermal evaporator influences marginally the evaporation temperature leading to quasi-isothermal evaporation of CO2. However, in single U-pipe configurations, small pipe diameter means lower pipe surface area and therefore higher thermal resistance. In Part II, all these advantages are taken into consideration toward proposing new geothermal evaporator configurations with multiple U-pipes (2 to 4 U-pipes in one borehole). R410A is also compared against CO2 for the new configurations. Operating parameters of all configurations were chosen so that CO2 and R410A are both subjected to a complete evaporation for equal total pipe surface area and equal heat extraction rate. Although all configurations have same total pipe surface area, it is shown that adding U-pipes and reducing pipe diameters diminishes borehole thermal resistance significantly. A novel configuration is also proposed to lower pressure drop of CO2 in the 4-U borehole configuration by insulating a portion of the downward U-pipe legs. Decreasing pipe dimensions by adding U-pipes while keeping total pipe surface area constant offers an opportunity to bundle pipes closer to each other and make the evaporator more compact as seen in the proposed Polymer Block configuration.

Experimental study on the effect of diameter on gas–liquid CCFL characteristics of horizontal circular pipes

The gas–liquid two-phase countercurrent flow in horizontal pipes is closely related to the safe operation of marine diesel engines with underwater exhausts, and nuclear power plants with pressurized water reactors. A visualization experiment on the effect of the diameter size on the counter current flow limitation (CCFL) characteristics of horizontal pipes was performed in the diameter range of 20–130 mm using air and water as the two phases. The results indicate that with a certain gas flow rate, the flow rate of the backflow liquid significantly increases with increasing diameter. Wallis models and those using the Froude–Ohnesorge numbers can correlate the effect of the change in diameter size when the diameters are greater than 100 mm, whereas they lose normalization capability with diameters less than 100 mm. From an analysis of the physical mechanism of formation of this diameter effect, a novel correlation model based on a new dimensionless group for each phase, consisting of the dimensionless inertia and dimensionless viscous force, was proposed for predicting the CCFL characteristics of small diameter pipes. Meanwhile, another correlation based on the Wallis model was also advanced for predicting the CCFL characteristics of large diameter pipes.

Weld quality inspection of small-diameter thin-walled pipes by a laser ultrasonic method.

Defect inspection of small-diameter thin-walled pipes is a difficult problem in the field of nondestructive testing. In this paper, a new detection method based on laser ultrasonics and guided circumferential wave technology is proposed and used to inspect the defects in pipes. First, a theoretical model based on the theory of acoustic propagation in solids is proposed for the small-diameter thin-walled pipes. The dispersion characteristics of the guided circumferential waves of thin-walled pipes are obtained by numerical simulation. Second, a laser ultrasonic system is constructed and used to detect the flaws in the small-diameter thin-walled pipes. Finally, the laser ultrasonic system is used to analyze the welding quality of stainless steel pipes with a diameter of 4.20 mm and a wall thickness of 0.30 mm. The experimental results are in agreement with the theoretical analysis, which demonstrates the reliability and practicability of the laser ultrasonic method in the weld quality inspection of small-diameter thin-walled pipes.

Recovery Throughput of Technological Pipelines and Useful Volume of Tanks for a Long Time Operated Pump Stations

The paper discusses the problems of cleaning technological pipelines and tanks to restore the capacity and useful volume capacity of oil pumping stations. The world experience of using chemical reagents for cleaning oil pipelines from asphalt-resinous paraffin deposits is considered, the disadvantages and advantages of the method are determined taking into account the restrictions that exist at the facilities of the main oil pipeline transport. The analysis of the results of experimental laboratory studies and pilot tests of the chemical washing technology at the existing facilities of Transneft PJSC is presented. Recommendations are given on improving the technology to reduce the consumption of chemicals and time costs. Particular attention is paid to the shortcomings and features of the use of hydrocarbon solvents for cleaning technological lines from pipes of small diameter and large tanks. The expediency of an additional physical effect is substantiated to increase the efficiency and rate of destruction and removal of hard-to-remove deposits, for which the use of ultrasonic resonators providing flow homogenization and dispersion is proposed.

Friction welding of fittings and nozzles from low-alloy steel 15Х2НМFА

ABSTRACT The purpose of this work is research and development of technology of friction welding instead of manual arc welding with coated electrode, fittings and pipes shell-type equipment of power plants of steel 15X2NMFA. Manual arc welding method does not provide a stable quality of welded joints. The solution to this problem is possible through the use of friction welding process fittings and pipes of small diameter. Given the lack of theoretical and experimental exploration of issues were raised and resolved the following scientific and technical tasks: developed by making constructive models and connected (cone) surfaces of the fittings (diameter up to 40 mm) and pipes (diameter up to 80 mm); choice of optimum training grounded corners conical surfaces to be welded; justified the choice of optimum welding parameters values; quality assessment of welded joints by non-destructive and destructive methods. Effect of constructive and technological factors on the quality of welded joints. Received the positive results of the pilot study confirmed the technological feasibility of friction welding fittings and pipes of small diameter low-alloy steel 15X2NMFA.