Surface Of Pipe Research Articles

Landslide control in the excavation of a shallowly buried tunnel with a large front slope

The tunnel with a large front slope is a common type of entrance in mountain tunnels. Excavation of this type of tunnel disrupts the original balance of the slope, which can easily lead to landslides or collapses. It is therefore important to choose suitable support for early reinforcement. This paper presents a case study of landslide control during the tunnelling of a shallowly buried tunnel with a large front slope. Three types of pre-support, including anti-slide pile, pipe roof and surface grouting, were used to control the landslide. In addition, a three-dimensional analysis was carried out to investigate the reinforcing effect of single and multiple pre-supports on the landslide and tunnel structure. The results showed that the deformation of the landslide and tunnel structure at the end of the entrance was the greatest, that is, the most dangerous, and the maximum slope displacement without pre-support was 15.1 cm. In tunnel structures, the arch area was the most prone to instability, while the bottom area did not experience significant deformation. The horizontal displacement control effect of the landslide body was ranked from strong to weak as surface grouting, pipe roof, and anti-slide pile, which is a decrease of 4.8%, 20.5% and 40.8% compared to the maximum displacement. While the vertical displacement control effect of the landslide was ranked from strong to weak as pipe roof, surface grouting, and anti-slide pile, which is a decrease of 4.3%, 45.1% and 63.7% compared to the maximum displacement. The reinforcement effect when three types of pre-supports were applied simultaneously was basically equal to the sum of the reinforcement effects when each pre-support was applied separately. This is mainly due to the different reinforcement mechanisms and areas of the three pre-supports, resulting in better overall effects.

Experimental investigation of thermal performance and entropy analysis of sphere turbulators

In this study, the effects of different numbers of sphere turbulators placed in a circular-shaped test pipe under turbulent flow conditions on heat transfer, friction factor, thermal performance factor and entropy production were experimentally investigated. Water was used as the working fluid in the experiments carried out in the number range Re=8379-16701. Initially, plain pipe and supported plain pipe experiments were carried out by keeping the fluid inlet temperature and test pipe surface temperature constant. Then, 1, 2 and 3 sphere turbulator experiments were carried out under the same conditions, respectively. According to the findings, the maximum Nusselt number increase compared to the supported plain pipe was 83.34% for the test pipe with 3 sphere turbulators. The minimum and maximum Nu number increase rates of 3 sphere turbulators compared to 1 and 2 sphere turbulators were obtained as 42.61%-46.93% and 13.99%-17.11%, respectively. The increase rates of maximum friction factors of 1, 2 and 3 sphere turbulators compared to the supported plain pipe were 174.42%, 226.70% and 306.53%, respectively. In addition, the maximum total entropy rate for sphere turbulators was obtained as 0.058 W.m-1.K-1 for 1 sphere turbulator at Re = 8379. In terms of the second law, the maximum entropy generation of sphere turbulators compared to the supported plain pipe decreased by 79.39% for 3 sphere turbulators at Re = 8379. As a result, it was concluded that the optimum number of sphere turbulators is 3 sphere turbulators with the lowest entropy production number and the highest TPF value (1.28).

Evaluation of the Primary Pipe Network at Banua Anyar Booster Pump as an Effort to Reduce Water Loss in the Service area of Northern Banjarmasin, South Kalimantan

Recorded as the best PDAM in South Kalimantan in Banjarmasin City. PT. Bandarmasih Perseroda Drinking Water (PAM Bandarmasih) is still facing the problem of high water loss rates of 29.07% in 2022, which is still far above the National Medium Term Development Plan (RPJMN) target with a minimum water loss value of 20%. One of the ways PDAM can reduce water loss is by evaluating the pipe network in a District Meter Area (DMA). This research focuses on evaluating the primary pipe network in the area served by the Banua Anyar booster which serves 18 DMAs. Network evaluation using EPANET 2.0 software. The evaluation results show that the diameter of the primary pipe from the booster pump to the Banua Anyar pipe bridge has quite high unit-head loss and flow velocity values due to flow friction with the pipe surface. It is necessary to change the diameter of the primary pipe used in the Banua Anyar booster network from a diameter of 400 mm to 600 mm which can reduce the rate of water loss by 6.3%. In the future, it is hoped that the value of water loss at PDAM Banjarmasin City can be reduced and the affordability of drinking water services for the people of Banjarmasin City can increase.

Numerical and experimental investigations on quasi-static component generation of longitudinal wave propagation in isotropic pipes

In this paper, the quasi-static component (QSC) generation of longitudinal waves propagating in an isotropic pipe is investigated numerically and experimentally. The three-dimensional (3D) finite element (FE) simulations are first carried out to gain physical insights into the characteristics of QSC generation from longitudinal wave travelling in an isotropic pipe with weak material nonlinearity. By applying the axial displacement excitation in the FE model, L(0, 1) mode and L(0, 2) mode are excited simultaneously. Then, the generated QSC pulses are extracted using the phase reversal approach for analysis. It is found that the QSC pulses generated by L(0, 2) mode and L(0, 1) mode are L(0, 1) mode. Meanwhile, the shapes of QSC pulses at different locations are extracted and compared. In this study, a data pre-processing method is proposed to handle numerically calculated and subsequent experimentally measured displacement signals, and a nonlinear acoustic parameter is defined to evaluate the incipient damages. After that, an experiment is conducted to measure the QSCs induced by the propagation of longitudinal waves in an aluminum pipe. The experimental results indicate that the propagation of longitudinal waves in the aluminum pipe can induce the QSCs. Different levels of corrosion are created on the surface of the aluminum pipe and are assessed by the generated QSCs. The results show that the nonlinear acoustic parameter has a monotonically increasing trend with the growing severity of corrosion. The QSCs generated by longitudinal wave can be used to detect and evaluate the early-stage surface corrosion in the aluminum pipe.

Farklı Isı ve Basınç Koşulları Altında Düz Bir Boru İçin Tek Yönlü Akışkan-Yapı Etkileşimleri Analizi

Numerical studies on stress, deformation, and damages due to fluid flow have been highly carried out using Fluid-Structure Interaction (FSI) in recent years. FSI is highly efficient in investigating a solid domain deformed by the fluid flow. In this study, a one-way fluid-structure interaction study is performed by a straight pipe under different pressure and thermal conditions. Here, the thermophysical properties of the fluid and mechanical properties of the solid domain can be subjected to change during fluid flow. An aluminum straight pipe with a 1 mm wall thickness is operated under 1 Bar, 5 Bar, and 10 Bar with three different surface temperatures -10ºC, 20ºC, and 50ºC. This study aims to investigate the structural variation of aluminum by the temperature and pressure change of operating fluid in the pipe. Variation of thermophysical properties of fluid by heated pipe surface is integrated into the numerical analysis by generated functions. Numerical analysis showed that the variation of temperature in operating fluid highly affects the fluid characteristic and the structural response of the solid domain by different temperatures. An increase in the operating pressure caused maximum deformation to approximately %100 from 1 Bar to 5 Bar, and approximately %120 from 1 Bar to 10 Bar for the adiabatic process as expected but in the heating conditions stress is nearly three times higher than cooling conditions. As a result, one-way FSI solutions are highly effective in investigating the deformed solid domain as a result of flow, thermal, and operating conditions.

Automatic Control of the Technological Regime in Devices with Enamel-Coated Inner Surface of Pipes

Automatic Control of the Technological Regime in Devices with Enamel-Coated Inner Surface of Pipes

A Numerical Study on Cross Flow Heat Exchanger with Different Reynolds (Re) Numbers

Heat exchangers are highly popular in engineering and industrial applications. Numerical studies on heat exchangers to investigate the performance of heat transfer have been carried out widely by Computational Fluid Dynamics (CFD) in recent years. In this study, a circular pipe with hot water in cross flow is investigated in different Reynolds (Re) numbers. Flow is turbulent flow and the Re number varies from 3165 to 4643 in the circular pipe. The air is at a temperature of 303 K and the water is at 333 K. Variation of flow characteristics and thermal performance is observed according to an increase in Re numbers such as Wall Shear Stress (WSS), Skin Friction Coefficient (Cf), Nusselt Number (Nu), heat transfer coefficient (h) and surface temperature of the circular pipe. Results show that there are no significant changes for the WSS and Cf values in the specified range of the Re number. However, when the thermal performance is evaluated, the temperature of the surface of the circular pipe, heat transfer coefficient, and Nu number values are increased by an increase in the Re number. Here, the increase is approximately 2% for the specified range of Re number, and it is shown that it can be increased by the flow conditions. The maximum Nu number is 4482.37 at the Re number of 4643. As a result, the Re number is highly effective in controlling the heat transfer performance of a heat exchanger

CALCULATION OF PIPELINES STRENGTH DUE TO MECHANICAL INFLUENCE OF ICE

Oil and gas pipeline systems contain structures in which ice expansion forces act on the pipes. The force of ice expansion on pipes can be internal and external. The internal force creates a hoop tensile stress in the pipe wall, the external force leads to the appearance of a compressive hoop stress and can lead to loss of stability of the pipe wall. To ensure the environmental safety of pipeline system operation in the oil and gas industry, it is necessary to determine the external and internal pressure on the pipes and evaluate their strength under the influence of ice expansion forces.Aim of research: ensuring environmental safety based on assessing the strength and stability of the pipe wall due to expansion forces of ice.Objects of study: environmental safety, pipeline or its sections under mechanical influence of ice.Research methods: theoretical studies of the stress-strain state of pipes due to external and internal expansion forces of ice.Analytical expressions were obtained to determine the pressure on the pipe surface due to ice formation in the interpipe space, as well as in pipeline cavity. An assessment of the influence of the properties of ice and soil in contact with the pipeline on the pressure values from the ice on the pipeline was made.

A simple parameter configuration scheme for a simplified dynamic model of pipe-embedded wall

A pipe-embedded wall (PE-wall) can effectively reduce the building load through the water circulation in the embedding pipes. Using renewable energy as an alternative, the water may be produced by solar water heater, or by cooling tower etc. This PE-wall may be used to reduce the building energy consumption, which is beneficial to achieve nearly zero energy building (nZEB) target. In this study, a simple parameter configuration scheme is proposed for the RC simplified dynamic model of the PE-wall. Based on the wall geometry and thermal properties, the scheme can directly determine thermal resistance (R) values and thermal capacitance (C) values for a 5R3C simplified dynamic model. The finite element frequency domain (FEFD) models and time-domain CFD models of three typical (i.e., light-weight, medium-weight and heavy-weight) PE-walls are established as reference. The simplified 5R3C model with parameters determined by the configuration scheme is validated in terms of their thermal responses both in frequency domain and time domain. Under specified dynamic boundaries, mean relative errors of heat flow on the internal wall surface and internal pipe surface are less than 5 %. The comparison results indicate the good accuracy and reliability of the parameter configuration scheme for the RC simplified dynamic model.

Mechanical response of concrete pipe rehabilitated by liner under external load: Analytical solution

AbstractUsing pipe lines to rehabilitate concrete drainage pipes is a popular trenchless technique. In this paper, the concrete pipe and liner are equivalent to a symmetrical structural mechanics problem, and the mechanical solution of the composite structure is obtained using the force method. Subsequently, the analytical solutions are compared with the test and finite element results. The distribution law of axial force, bending moment, and shear force of the composite structure are obtained, and the circumferential strain law of the inner and outer surfaces of the host pipe is analyzed. Lastly, the influence of pipe diameter and liner thickness on the bearing capacity of the host pipe is examined. The results indicate that the axial and shear force distribution of the composite structure remains the same for different pipe diameters, as the distribution diagrams of shear and axial force along the circumferential direction coincide. While the elastic modulus and thickness of the liner have no effect on the internal force distribution of the composite structure, they do directly affect the stress state of the host pipe. Additionally, the bottom support causes abrupt changes in the bending moments and strains of the host pipe.

Environmental Risk Assessment of Hydrocarbon-Rich Sludge of a Gas Refinery Using the Integrated Approach of PMBOK Standard Risk Management and FMEA Technique: A Case Study

Background: The present study aimed to assess the potential hazards of hydrocarbon-rich gas refinery sludge from the South Pars Gas Complex-First Refinery, Iran, and to analyze how these risks could impact the project goals based on the Project Management Body of Knowledge (PMBOK) guidelines. Methods: Statistical population of this analytical, cross-sectional survey was 31 health, safety, and environment (HSE) experts from the study refinery selected by purposeful sampling. Environmental, health, safety, and technical risks were categorized and identified using the PMBOK guidelines. Delphi method and 5-point Likert scale questionnaire were employed to assess the significance of each risk. Priority one risks within each category were determined using Primavera Risk Analysis version 8.7 software. Results: Following three Delphi steps, 17 out of 77 primary risks were identified and finalized. The first rank with the highest weight corresponded to time and cost group (the risk of soil contamination via sludge stored in the burn pit due to aliphatic and aromatic hydrocarbons), human resources group (radioactive materials accumulated on the inner surfaces of pipes, valves, pumps, heat exchangers, tanks, boilers and other equipment and the risk of these materials being hazardous for human health), and quality group (failure to supply equipment and quality control systems and personal protective equipment). Conclusion: The research findings pinpointed 17 risks within various domains, encompassing time and cost, human resources, quality, contract, scope, and communication. These identified risks necessitate a comprehensive, integrated approach to risk management for effective mitigation and resolution.

Investigation into the mechano-electrochemical interaction of internal and external corrosion defects on pipe surfaces

Revealing the mechanical-electrochemical interactions (M-E) on internal and external defects in pipelines is of paramount importance for ensuring the safe operation of pipelines. The present study establishes a mechano-electrochemical multi-physics coupling model and develops a two-dimensional finite element (FE) model of internal and external defects on the pipe surface to investigate the M-E interaction of X100 steel pipe with corrosion defects on both internal and external surfaces. The results demonstrate that the M-E interaction is significantly influenced by the geometrical shape, relative position, and internal pressure of defects. Moreover, altering a single defect parameter can simultaneously impact the M-E interaction of two defects. As the depth of defects increases, the cross-sectional area between internal and external defects decreases, leading to an intensified interaction between mechanics and electromagnetics and a gradual concentration of M-E interaction at the center of defects. The magnitude of the M-E interaction exhibits a negative correlation with the length of the defect, while the presence of a long defect minimally impacts the M-E interaction on the opposing side. As the external defects gradually distance themselves from the internal defects, the M-E interaction diminishes and the concentration area of M-E interaction shifts in the opposite direction to defect migration, while stress in the non-defect region adjacent to both internal and external defects progressively intensifies. The increase in internal pressure significantly enhances the M-E interaction of internal and external defects, with the M-E interaction primarily focused on the minimum cross-sectional area of radial overlap between these defects. At low internal pressures, however, the M-E interaction becomes negligible.

Simulation of Saturated Vapor Condensation from a Downflow on the Surface of a Horizontal Pipe by the VOF Method

Simulation of Saturated Vapor Condensation from a Downflow on the Surface of a Horizontal Pipe by the VOF Method

Urban rainstorm and waterlogging scenario simulation based on SWMM under changing environment.

Urban rainstorm and waterlogging occurred more frequently in recent years, causing huge economic losses and serious social harms. Accurate rainstorm and waterlogging simulation is of significant value for disaster prevention and mitigation. This paper proposed a numerical model for urban rainstorm and waterlogging based on the Storm Water Management Model (SWMM) and Geographic Information System (GIS), and the model was applied in Lianhu district of Xi'an city of China. Furthermore, the effects of rainfall characteristics, pipe network implementation level and urbanization level on waterlogging were explored from the perspectives of spatial distribution of waterlogging points, drainage capacity of pipe network and surface runoff generation and confluence. The results show that: (1) with the increase of rainfall recurrence period, the peak of total water accumulating volume, the average decline rate of water accumulating volume and the number of waterlogging nodes increase; (2) optimizing the pipe diameter can shorten the average overload time of the pipe network from the entire pipe network, but for a single pipe, optimizing the pipe diameter may lead to overloading of unoptimized downstream pipeline; (3) the lower the imperviousness, the less the number of waterlogging nodes and average time of water accumulating, and (4) the west, northwest and southwest areas are relatively affected by the imperviousness, only improving the underlying surface conditions has limited influence on waterlogging in the study area. This study can provide reference for urban waterlogging prevention and reduction and pipe network reconstruction.

Application of Ice Pigging in a Drinking Water Distribution System: Impacts on Pipes and Bulk Water Quality

Ice pigging is an emerging technique for pipe cleaning in drinking water distribution systems. However, substantial confusion and controversy exist on the potential impacts of ice pigging on bulk water quality. This study monitored the microstructural features and composition of sediments and microbial community structures in bulk water in eight multimaterial Chinese networks. Chloride concentration analysis demonstrated that separate cleaning of pipes with different materials in complex networks could mitigate the risk of losing ice pigs and degrading water quality. The microstructural and trace element characterization results showed that ice pigs would scarcely disturb the inner surfaces of long-used pipes. The bacterial richness and diversity of bulk water decreased significantly after ice pigging. Furthermore, correlations were established between pipe service age, temperature, and chloride and total iron concentrations, and the 15 most abundant taxa in bulk water, which could be used to guide practical ice pigging operations.

Online micro defects detection for ductile cast iron pipes based on twin light photometric stereo

Ductile cast iron pipes (DCIPs) are widely utilized in water and gas supply due to their exceptional mechanical and material properties. Quality control during production is paramount for optimal performance, with surface defect detection being of utmost importance. Currently, production sites primarily rely on manual visual inspection, which presents several challenges, including high labor intensity, low efficiency, and subjectivity in defect judgment. 2D detection algorithms based on single images struggle to effectively detect small defects such as pores, pinholes, and scratches, resulting in high missed detection rates and vulnerability to interference from oil and water stains. To address these issues, this paper proposes a symmetrical twin-light photometric stereo (TLPS) detection algorithm based on photometric stereo theory, and image correction algorithm for mitigating the effects of ambient light. A visual inspection prototype system was designed and successfully implemented at a production site. The system comprises eight visual inspection units, each equipped with a high-speed line scan camera and two bar light sources for image acquisition of moving DCIP. Under the Lambertian model and parallel light source assumption, the gradient expression in the texture direction of the DCIP surface is derived based on light source symmetry. Production experiment results demonstrate that the gradient map obtained through the proposed TLPS effectively enhances defect contrast and accurately detects and locates micro defects such as pores, pinholes, and scratches on cast pipe surfaces. This verifies the effectiveness of the TLPS algorithm, addresses the shortcomings of traditional 2D detection algorithms, and lays the foundation for subsequent online detection of DCIP surface defects.

Effects of Reynolds Number on the Volume Concentration of Al2O3 in Ethylene Glycol

The nanofluid is suspension of nanoparticles in the base fluid used to enhance the heat transfer rate in many applications of heat transfer. The Reynolds number is the dimensionless number used to characterize the flow of the nanofluid to enhance the heat transfer rate. The current study, the effects of Reynolds number on 0.01% volume concentrations of the aluminium oxide (Al2O3) nanoparticles in the ethylene glycol through the flow in the pipe are investigated. In the study, ethylene glycol is considered as the base fluid. The thermophysical characteristics of the Al2O3/EG nanofluid were determined in the current work using a cylindrical copper pipe with an 8 mm diameter and 400 mm length. The heat transfer coefficient (HTC) and Nusselt number were calculated for the Reynolds number varied from 200 to 1200, considering nanofluid inlet temperature of 298 K and constant heat flux at the wall surface of pipe 1100 W/m2 K. The findings showed that the HTC and Nusselt number of the nanofluid flow in the pipe increased as the Reynolds number increased. Further, an exponential correlation was proposed for variation of the Reynolds number with HTC and Nusselt number for the obtained results. ANSYS Fluent software was used for the analysis of the nanofluid flow though pipe.

A Self-Supervised Model Based on CutPaste-Mix for Ductile Cast Iron Pipe Surface Defect Classification.

Online surface inspection systems have gradually found applications in industrial settings. However, the manual effort required to sift through a vast amount of data to identify defect images remains costly. This study delves into a self-supervised binary classification algorithm for addressing the task of defect image classification within ductile cast iron pipe (DCIP) images. Leveraging the CutPaste-Mix data augmentation strategy, we combine defect-free data with enhanced data to input into a deep convolutional neural network. Through Gaussian Density Estimation, we compute anomaly scores to achieve the classification of abnormal regions. Our approach has been implemented in real-world scenarios, involving equipment installation, data collection, and experimentation. The results demonstrate the robust performance of our method, in both the DCIP image dataset and practical field application, achieving an impressive 99.5 AUC (Area Under Curve). This presents a cost-effective means of providing data support for subsequent DCIP surface inspection model training.

Picosecond pulsed 532nm laser system for roughening and secondary electron yield reduction of inner surfaces of up to 15m long tubes.

Laser-induced surface structuring is a promising method to suppress electron mulitpacting in the vacuum pipes of particle accelerators. Electrons are scattered inside the rough surface structure, resulting in a low Secondary Electron Yield (SEY) of the material. However, laser processing of internal pipe surfaces with a large aspect ratio is technologically challenging in terms of laser beam guidance and focusing. We present a 532nm ultrashort-pulse laser setup to process the inner parts of 15m long beam vacuum tubes of the Large Hadron Collider (LHC). Picosecond pulses at a repetition rate of 200kHz are guided through an optical fiber toward an inchworm robot traveling inside the beam pipe. The system was installed, characterized, and tested for reliability. First surface treatments achieved the required scan precision. Cu2O-dominated nano-features were observed when processing at high average laser power (5 W) and slow scanning speed (5mms-1) in nitrogen flow, and the maximum SEY of copper was decreased from 2.1 to 0.7.

Numerical Investigation of the Effect of the Wall Properties on Downward Mercury Flow and Temperature Fluctuations in a Vertical Heated Pipe under a Transverse Magnetic Field

The work is motivated by the need to study the effect of abnormal quasi-periodic high-amplitude temperature fluctuations in a liquid metal flow in pipes and channels, which arise under conditions close to those specific for liquid metal (PbLi alloy, etc.) hydrodynamics and heat transfer in blankets of tokamak fusion reactors. Such temperature fluctuations in the cooling channels of the fusion reactor blanket pose a threat to the strength of the channel walls. The influence of the physical properties of the channel walls and potential fouling of their inner surface on the generation of these fluctuations has not been studied as yet. Therefore, this problem has been numerically investigated for a MHD mixed convection of a liquid metal in a round tube for a downward flow of mercury with the one-side heating condition under a strong transverse magnetic field using conjugate problem statement by the LES (Large Eddy Simulation) method. Numerical simulation was performed for four cases: (i) the effect of thermophysical and electrophysical properties of the steel pipe wall is neglected, (ii) the effect of wall material properties is included, (iii) the effect of the moderate contact electrical resistance caused by a layer of fouling deposits or oxides on the inner surface of the pipe is accounted for, and (iv) the resistance of the thin fouling layer is assumed to be very high. The predictions for the cases (i) and (iv) are in good agreement with the experimental data and the results of the direct numerical simulation. They demonstrate the existence of quasi-periodic abnormal high-amplitude temperature fluctuations in the fluid with a frequency of approximately 0.14 Hz. With a relatively low electrical resistance of the fouling film (case iii), the frequency of high-amplitude temperature fluctuations was considerably lower (0.07 Hz). In the absence of electrical contact resistance on the inner surface of the steel pipe (case ii), high-amplitude velocity and temperature fluctuations were not revealed in the fluid. Thus, it was shown for the first time that the physical properties of a wall and the electrical resistance between the fluid and the electrically conducting wall were responsible for the development of abnormal temperature fluctuations in the liquid and the wall and control of their amplitude and frequency. The causes of the revealed effects are discussed.