Pipe Fittings Research Articles

Physical and Numerical Simulation Study on Structure Optimization of the Inner Wall of Submerged Entry Nozzle for Continuous Casting of Molten Steel

The submerged entry nozzle (SEN) plays an important role in the continuous casting production process. It is a cast refractory pipe fitting installed in the lower part of the tundish and inserted below the molten steel level of the mold. It not only affects the speed of molten steel flow, but is also prone to nodules and affects production. In the present work, the flow behavior of molten steel in a traditional nozzle and that in a new type of nozzle whose inner wall was distributed with arrays of hemispherical crowns were studied by means of both physical simulation (using a water model) and numerical simulation (using ANSYS CFX) based on the prototype of a production continuous casting slab mold. Both experimental and numerical simulation results show that, compared with the traditional nozzle, the impact depth generated by the new-type nozzle in the mold is reduced by 21.06–26.03 cm, the impact angle is reduced by 14–17 degrees, and swirl flow was generated inside the new-type nozzle, which not only improves the flow characteristics inside the submerged entry nozzle and changes the dead zone size in the submerged entry nozzle, but also improves the velocity distribution at the outlet of the nozzle and minimizes the possibility of nodulation. In addition, in contrast to the traditional nozzle that generates flat body-shaped jets of molten steel flow, the new-type nozzle produces baseball glove-shaped jets that penetrate shallower into the molten steel bath in the mold, which significantly reduces the outlet velocity and is conducive to the floating of inclusions.

Predicting Forming Defects in Thin-walled Circular Tubes Made of A286 Based on Deform-3D

We conduct a study on the thin-wall characteristics of a certain type of A286 thin-walled pipe fittings during the swaging forming process, focusing on the issues of folding and incomplete filling. In order to explore the forming mechanism of defects in thin-wall pipe fittings, the Deform-3D finite element software is utilized for numerical simulations. Through analysis of the forming results, equivalent stress, equivalent strain, material flow lines, and material flow patterns during the swaging forming process, it is found that the occurrence of defects in the thin-wall pipe fittings during the forming process is closely related to the material flow behavior. When the material flows in a positive extrusion manner during the thin-wall feature forming process, the specimen exhibits obvious folding defects. Moreover, there is significant stress concentration occurs in the transition region between the rod and the head.

3D free thermal bending of BR1500HS high-strength steel tube: Simulation and experimental investigation

Ultra-high strength steel (UHSS) pipes find widespread application in the automotive industry. To address the challenges associated with forming complex structural parts from UHSS pipes, the three-dimensional free thermal bending (3D-FTB) technology for UHSS pipes based on a robotic arm and a bending roller mold was firstly developed. A finite element simulation prediction model for accurately describing the forming process is established and discussed. In this paper, the thermal-mechanical coupling model of the material is established by Gleeble thermal tensile test and modified Arrhenius model. The effects of parameters such as current frequency, current density, axial feed rate, and quenching conditions on forming temperature and microstructure transformation are thoroughly investigated via finite element simulation analysis. The mechanical properties and potential defects of the pipe fittings after forming are analyzed and validated experimentally. The results demonstrate that the finite element simulation and analysis method based on the thermal-force coupling model of the BR1500HS UHSS pipe can accurately predict the forming process parameters. The optimal process conditions are identified as follows: current frequency of 55 kHz, current density of 650 A/mm2, and feed rate of 8 mm/s. Under these parameters, the austenite transformation rate of the pipe fittings reaches an impressive 98 % and the maximum tensile strength reaches 1540 MPa. Lastly, the overall wall thickness distortion rate of the formed pipe remains below 0.2 % and the bending rebound angle exhibits an average reduction of over 80 % compared to that under room temperature conditions.

Stress Classification Lines for Non-Standard Y-Tee Design in Piping System

All processes fluids in the oil and gas industry are generally transferred from one point to another via complex piping networks. The process temperature and the pressure of the fluids may vary between -21 °C to 816 °C and from atmospheric, 1.013 barg to 431 barg, respectively. Under these conditions, the entire piping networks are exposed to thermal expansion and contraction resulting in mechanical bending, potentially causing mechanical failures. The most common pipe fitting used in piping networks to divide the fluid flow into two different directions would be a standard equal tee which was designed in accordance with ASME B16.9. The equal tee, however, has distinctive flexibility characteristics compared to the pipe, which is well defined in ASME B31.3. These flexibility characteristics generate a stress intensification factor (SIF) through bending moment equations for beam-type element analysis for standard equal tee components. However, due to the limitation of SIF and flexibility characteristics for the non-standard pipe fittings, the stress evaluation could not be done using beam-type element analysis. When using finite element method (FEM) analysis, generally equivalent stresses (Von Mises or Tresca) or principal stresses would be evaluated depending on the stress categorization as explained in ASME codes and standards. In this paper, a stress evaluation method for non-standard Y-tee was developed and demonstrated against ASME VIII Div. 2 Part 5 requirement. The developed SCLs line for the non-standard Y-tee fittings provides the guides for stress assessment against design stress allowable. An optimum design for non-standard Y-tee is proposed at 45° and 60° crotch radii which resulted in lower stress value at SCL lines, hence improving the structural integrity.

Research on Performance Test of the Optic-Electric Sensors for Reservoir Landslide Temperature Field Monitoring

In recent years, with the superposition of extreme climate, earthquakes, engineering disturbance and other effects, global landslide disasters occur frequently. Due to reservoir landslides being mostly in a multi-field coupling environment, the temperature field will impact the deformation and seepage fields, thereby affecting the stability of the reservoir landslide. The variation in the landslide’s surface temperature also directly affects the stress and deformation of deep rock masses. If hidden dangers are not detected in time, and corresponding measures are implemented, it is easy to cause landslide instability. In order to clarify the temperature measurement performance of different optic-electric sensors and the application characteristics of layout techniques, laboratory calibration tests of temperature sensors under different adhesives and attachment materials are carried out in this paper. It was found that the test data of the iron bar had the best effect among the four attachment materials overall. Therefore, the bar with a high-stiffness material should be preferred when selecting a pipe fitting as the fiber Bragg grating (FBG) temperature attachment in the borehole. However, considering the high requirements for the durability of sensors and layout techniques in on-site monitoring, the long-term stability of the adhesives used in actual monitoring needs to be improved. At the same time, it was found that the platinum 100 (PT100) temperature sensor has relatively higher testing accuracy (A: 0.15 + 0.002 × |t|; B: 0.30 + 0.005 × |t|), a larger temperature measurement range (−200~+850 °C) and better temperature measurement stability when compared to conventional sensors. Moreover, its resistance value has a good linear relationship with temperature. Finally, the Xinpu landslide in the Three Gorges Reservoir area was selected as the research object for on-site monitoring. There was a high correlation between the on-site monitoring results with the laboratory calibration test results. Therefore, through the performance test of optic-electric sensors in reservoir landslide temperature fields, more accurate solutions can be provided for selecting sensors and designing layout techniques to monitor the underground temperature field of landslides under different geological conditions. Thereby, grasping the real-time state information of the reservoir landslide temperature field is achieved accurately, providing an important reference for early warning, prediction, prevention and the control of reservoir landslide disasters.

Optimization for Pipeline Corrosion Sensor Placement in Oil-Water Two-Phase Flow Using CFD Simulations and Genetic Algorithm.

Internal corrosion is a major concern in ensuring the safety of transmission and gathering pipelines in Structural Health Monitoring (SHM). It usually requires numerous sensors deployed inside the piping system to comprehensively cover the locations with high corrosion rates. This study presents a hybrid modeling strategy using Computational Fluid Dynamics (CFD) and Genetic Algorithm (GA) to improve the sensor placement scheme for corrosion detection and monitoring. The essence of the proposed strategy harnesses the well-validated physical modeling capability of the CFD to simulate the oil-water two-phase flow and the stochastic searching ability of the GA to explore better solutions on a global level. The CFD-based corrosion rate prediction was validated through experimental results and further used to form the initial population for GA optimization. Importantly, fitness was defined by considering both sensing effectiveness and cost of sensor coverage. The hybrid modeling strategy was implemented through case studies, where three typical pipe fittings were used to demonstrate the applicability of the sensor layout design for corrosion detection in pipelines. The GA optimization results show high accuracy for sensor placement inside the pipelines. The best fitness of the U-shaped, upward-inclined, and downward-inclined pipes were 0.9415, 0.9064, and 0.9183, respectively. Upon this, the hybrid modeling strategy can provide a promising tool for the pipeline industry to design the practical placement.

Experimental investigation on the effect of heat treatment parameters on the mechanical and microstructural properties of an ASTM A860 WPHY 65 pipe fitting

In order to optimize the heat treatment process following hot induction forming, our study focused on investigating the impact of quenching and tempering temperature on the mechanical properties and microstructure of ASTM A860 Gr WPHY 65 hot formed 30-inch elbow steel, which is utilized in high strength low alloy (HSLA) pipelines for oil and gas applications. The desired properties for these steels include high mechanical strength, toughness, ductility, and weldability. Our experimental approach involved varying the soaking temperatures at 960 °C, 1000 °C, and 1050 °C, and subsequently cooling the samples in water at 20 °C, followed by tempering at 670 °C and 700 °C. Through the use of experimental design techniques, we determined the optimal heat treatment parameters. The results indicate that soaking at 1050 °C and tempering at 700 °C were the most effective treatment conditions in terms of mechanical strength. Furthermore, microstructural analysis revealed that heat treatment not only restored the microscopic structure of the base material, but also resulted in finer grain sizes.

Parameter Study of a Loss Reducing Passive Flow Control Method in a Square-to-square Sudden Expansion

The energy consumption of mechanical ventilation in buildings needs to be reduced. An efficient way to achieve this goal is to reduce the hydraulic resistance of the ventilation duct system elements, for example, that of sudden expansions. Ventilation ducts and pipe fittings are frequently of rectangular cross-section. The present paper investigates a passive flow control method in order to reduce the loss coefficient of a square-to-square sudden expansion, where the loss-reducing appendages are short guide vanes, termed as miniflaps, placed at the step edge of the sudden expansion. The turbulent flow is examined numerically using the generalized k-ω model of the Ansys Fluent software for different area ratios of the sudden expansion, miniflap lengths, and miniflap angle setups. The Reynolds number is kept constant at 1.08·105. Based on the results of the numerical simulations, the loss coefficient of the sudden expansion can be reduced by ~20–25% for an optimum miniflap angle between 9° and 12°. Increasing the length of the miniflaps leads to a greater reduction of the loss coefficient up to a miniflap length of 0.3 dh1, where dh1 is the upstream hydraulic diameter of the duct.

Failure Risk Prediction Model for Girth Welds in High-Strength Steel Pipeline Based on Historical Data and Artificial Neural Network

Pipelines are the most economical and sensible way to transport oil and gas. Long-distance oil and gas pipelines consist of many steel pipes or pipe fittings joined by welded girth welds, so girth welds are an essential part of pipelines. Owing to the limitations of welding conditions and the complexity of controlling weld quality in the field, some defects are inevitably present in girth welds and adjacent weld areas. These defects can lead to pipeline safety problems; therefore, it is necessary to perform failure risk assessment of pipeline girth welds. In this study, an artificial neural network model was proposed to predict the failure risk of pipeline girth welds with defects. Firstly, many pipeline girth weld failure cases, pipeline excavation, and inspection data were collected and analyzed to determine the main factors influencing girth weld failure. Secondly, a spatial orthogonal optimization method was used to select training samples for the artificial neural network model to ensure that the training sample set could cover the feature space with a minimum number of samples. Thirdly, a prediction model based on BP neural networks was established to predict the failure risk levels. The training dataset/testing dataset was 602/4215, and the prediction accuracy for all risks of girth welds achieved an acceptable level. This study can provide a valuable reference for pipeline operators to prevent pipeline accidents.

Generation of experimental data for model training to optimize fouling prediction

AbstractTo successfully deal with a complex fouling problem usually entails a good understanding based on a broad spectrum of additional data. Meanwhile, a huge amount of process data is recorded and may be utilized to create a better understanding and prediction of the fouling status of an apparatus or the entire production plant. We propose a systematic approach to generate training data in a pipe fitting as a pre-step before the potential use of the entire data set of the production plant, irrespective of the relevance for the fouling prediction. Therefore, a temperature-based detection of the heat transfer resistance of plastic discs (representing 'artificial’ fouling) and a particulate material deposition (representing ‘real’ fouling) was applied in a pipe fitting obtaining reproducible results. The parameter variation experiments exhibit linear fouling curves and are therefore very suitable for model training. The temperature measurements confirm a correlation between the obtained temperature drop and the layer thickness of the plastic discs as well as the deposited particle fouling mass.

Optimizing the Construction of the NUWSP SPAM Piping Network in Gresik Regency

Water is essential for all living things, including humans. Water, both in terms of quality and quantity, will have an effect on human life. The Indonesian government is preparing the National Urban Drinking Water Supply Plan (NUWSP) with assistance from the World Bank. A significant portion of the Bank's financial resources are allocated to technical assistance and capacity building in support of the Indonesian government's infrastructure expenditures in all urban water distribution platforms. The NUWSP Work was implemented during an 11-month period, from November 18, 2021 to August 22, 2022, with the NUWSP Work Location at Gresik Regency in East Java. During the data collection stages, both primary and secondary data were obtained. The drinking water supply system (SPAM) planning stage comprises calculating BOQ and RAB, as well as DED for drinking water, and planning for the drinking water JDU system. The contractor takes measurements and standards before installing a field-specific bow plank at the tying point. To avoid pipe damage, individual pipe fittings must be lowered into the trench using the right equipment. The volume of excavation is computed using a depth of 180 cm, a breadth of 60 cm, and a length of excavation of 31 km from six pieces of a pipeline. The Bill of Quantity (BOQ) and Budget Plan (RAB) necessary to complete the SPAM pipeline network work in Gresik Regency were IDR 27,823,590,000.00, based on the results and discussion of the Optimization of SPAM Network Work (NUWSP) in Gresik Regency.

Water Hammer Arresters; Review Studies and Practical Experiments for Alternatives

The current research deals with practical studies that explain to the Iraqi consumer multiple instances about the phenomenon of water hammer which occur in the water pipeline operating with pressure. It concern a practical study of the characteristics of this phenomenon and economically harmful to the consumer the same time. Multiple pipe fittings are used aimed to reduce this phenomenon and its work as alternatives to the manufactured arresters that used to avoid water hammer in the sanitary installations, while the consumer did not have any knowledge as to the non-traded for many reasons, including the water pressure decreases in the networks and the use of consumer pumps to draw water directly from the network. Study found a number of conclusions and recommendations of some of the most important pipe fittings have been effective in curbing this phenomenon, as reflected in the illustrations included in the search.

Study on the Hydrodynamic Performance and Stability Characteristics of Oil-Water Annular Flow through a 90° Elbow Pipe

The transportation of highly viscous oil surrounded by water annulus has been recognized as a feasible option in terms of low-energy consumption and high efficiency. During the process of heavy oil delivery, the problem of pipe fittings is inevitably encountered, and the most common one is elbow assembly. In this present study, simulations for oil-water core annular flow (CAF) through a 90° elbow pipe were performed by computational fluid dynamics (CFD) based on VOF, standard k-ε, and CSF models. Simulation results were consistent with experimental data, which verifies the validity and practicability of the proposed model. The effects of inlet water fraction, superficial velocities of oil and water, oil properties (density and viscosity), and pipe geometry-related parameters (diameter ratio, wall roughness, and surface wettability) on the hydrodynamic performance and stability characteristics were explored. It is revealed that inlet water fraction, superficial velocities of oil and water, oil properties, and pipe geometric parameters do influence the volume fraction of oil and the stability of the water ring. Furthermore, the oil core may adhere to the downstream of the 90° elbow pipe under certain operational conditions. The results could provide a reference for the design of 90° elbow pipe structures and the optimization of operation parameters.

Mathematical Geometric of Open and Closed Valve in Water Hammer

A valve is a device used to control the flow of the fluid. The control is achieved by closing, opening or partially obstructing various passageways. Valves have many applications and the valves are considered to be pipe fittings, and there are many different valve designs. Each of the many different valve designs has its own advantages and disadvantages. For example, the gate valve slides up and down like a gate, the globe valve closes a hole placed in the valve, the angle valve is a globe valve with a 90° turn, and the check valve allows the fluid to flow only in one direction. In this paper, the present investigation is to explore the effect open and close valve on water hammer and study the valve types with equations for every valve, the results give information about the pattern of valve closing and valve opening crescent water hammer.

Effect of pipe size on erosion measurements and predictions in liquid-dominated multiphase flows for the elbows

Solid particle erosion in pipelines and pipe fittings occurs when solids are produced in the oil and gas industries during transporting fluids. Erosion of elbows in series for liquid-dominated flows has gained recognition as many oil fields operate in deep-water subsea flow lines and also in conventional wells onshore. Although significant data is available for gas-dominated flows, the data for liquid-dominated flows are scarce and limited to 50.8 mm pipe elbows in dispersed bubble flow only. Thus, it is essential to determine erosion for different pipe sizes to investigate the pipe size effect and for different flow regimes. This work conducts experiments in vertical liquid-solid flows, and liquid-gas-solid churn flows to examine erosion using 340 μm sand particles in 50.8 mm and 76.2 mm standard SS316 elbows in series separated at a distance of three diameters between them. In addition, flow visualization and paint-removal experiments are conducted to predict the erosion patterns in the elbows. Furthermore, Computational Fluid Dynamics (CFD) simulations are performed to simulate the experimental conditions. Eulerian and VOF multiphase models with different turbulence models are used in CFD simulations to predict erosion on the elbows in series and compare with the experimental results. The CFD results, when modified to account for the lubrication effects of the liquid, can predict the experimentally observed erosion pattern and the magnitudes.

Modeling of sand transport and elbow erosion in horizontal two-phase slug flow

Horizontal wells play an important role in maximizing the recovery of hydrocarbons from oil and gas reservoirs. During production, if the rate of production of produced fluids with sand particles is low, the deposition of sand particles in horizontal flow lines can wreak havoc on production systems in such a way as to cause increased pressure loss and reduction or loss of production when the pipe is partially or completely blocked. On the other hand, if the production rate of fluids is high, the impact of sand particles on the wall of the pipe will erode the inner surface of the pipe fittings. In this case, erosion can be severe enough to cause a hazardous spill and complete shutdown of systems. Therefore, it is important to quantify the sand transport and erosivity of different flow regimes. Under moderate velocities, there exists a flow regime which is called slug flow which is characterized by the intermittent appearance of liquid slugs propagating through the pipe. Studying the sand deposition and erosion due to sand particles entrained in intermittent flows is extremely difficult since the solid particle velocity magnitudes are coupled with several multiphase flow parameters such as phase distribution and slippage between the phases. This work focuses on the improvement of mechanistic models for predicting critical deposition of sand particles in horizontal pipes and erosion in horizontal-horizontal elbows. In this investigation, a modified model is proposed to better predict the critical deposition velocity and the characteristic particle velocity as a function of the slug flow characteristics. The model predictions are compared with the sand transport and erosion data collected at the University of Tulsa and other research institutions. The results show that the new approach provides improved predictions for sand transport and maximum erosion in standard elbows when compared with existing models.

Comprehensive Parameter Screening for the Investigation of Particulate Fouling in Pipe Fittings

AbstractA prominent example of unwanted accumulation in production plants is particulate fouling, which has been subject of many studies in apparatuses. However, pipe fittings have attracted little attention despite their large number in production plants. Here, the influence of process parameters and geometry factors on the fouling in pipe fittings is investigated under isothermal conditions that aims to an improved understanding of their fouling behavior. The variation of fitting type and size, the run time and particle mass fraction have the greatest impact on the fouling mass while the temperature does not influence the result.

Design and Implementation of Automatic Switching Exhaust Method and Air Intake Method Bell Prover Gas Calibration Facility

As the classical bell prover gas calibration facility has the feature that is exhaust method or air intake method alone, in this paper, a new automatic bell prover gas calibration facility that combines the exhaust method and air intake method is designed. Firstly, the flowmeter, pipelines, and other related pipe fittings are mounted in advance. Then, through the system software, control on-off valves condition to switch different pipelines direction and select expected items. Lastly, the system collects the experimental dates to realize the exhaust method and air intake method altogether automatically. The newly designed facility doesn’t need to change lines manually which is time-consuming and laborious, and the calibration results are accurate and reliable as well. At the same time, the new facility which can be reconstructed from the original facility has a compact structure and small occupancy space, and it is easy to implement and has good practical and promotional value.

Effects of Pipe Fittings on the Pump Energy Requirements of a Piping System

The number of pipe fittings, as well as their type in a piping system, are very important despite generating minor energy losses that, in many cases, are not considered. However, these losses become very significant for high mass flow rates, directly affecting the energy requirements of the pump. This study presents an analysis where the energy requirements of the pump have been calculated from different numbers and types of elbows and valves, showing exactly the working conditions where the energy losses start to be significant. Three case studies have been developed to observe the behavior of the energy requirement of the pump: effect of the number of elbows and flow rates, interaction of the number of elbows–pipe diameters–flow rates, and the effect of the number of valves on the power of the pump. It has been observed that the effect of the workflow and the type of elbow on the pump power is not significant when the number of elbows is three. When the number of elbows is increased to 10, two zones arise, i.e. the zone of non-significant effect when the flow rate is lower than 9 L/s, and the zone of significant effect when the flow rate is greater than 9 L/s. For flow rates lower than 6.75 L/s, the number of ball valves has no significant effect on the increase in the energy requirement of the pump; it increases only 0.73 kW. For flows higher than 11.3 L/s, a zone of high energetic requirements, which depends on the number of valves used, has been identified.

Numerical simulation of solid particle erosion in the gas-liquid flow of key pipe fittings in shale gas fields

Erosion caused by solid particles is one of the important reasons for the failure of shale gas gathering pipelines. However, the erosion laws of right-angle pipe and blind tee were rarely compared in previous studies, and the parameter settings almost did not meet the actual requirements of shale gas exploitation. The aim of this paper is to study the erosion laws of 90° elbow, right-angle pipe and blind tee based on the production parameters of a gas field. CFD-DPM approach integrates the Mixture model, the Discrete Phase Model, and an erosion model is employed to predict solid particle erosion in gas-liquid two-phase flow in the shale gas field. The results show that the maximum erosion rate of pipe wall increases exponentially with the fluid velocity. With the development of mining, the lower the free water content, the more serious the pipe wall erosion. In addition, under the same working conditions, the blind tee is relatively erosion-resistant compared with 90° elbow and right-angle pipe. The shale gas gathering and transmission system can use blind tees to connect pipes and limit fluid velocity, so as to prolong service life and ensure flow safety.