Pipeline Pressure Research Articles

Research on the characteristics and protection of water hammer in long-distance dual-pipe water supply systems.

Hydraulic transients in long-distance pressurized water pipelines significantly impact their normal operation. This study develops a one-dimensional mathematical model for pressurized water pipelines using the method of characteristics and incorporates water hammer equations for dual-pipeline systems. The model is validated with experimental data, and simulations are conducted under real engineering conditions, focusing on valve closure operations. The analysis examines the transient responses for varying valve closure times (T) and the effect of installing surge tanks. Results show that increasing valve closure time and installing surge tanks both mitigate water hammer impacts. Specifically, when valve closure time exceeds 300 seconds, surge tanks reduce maximum pressure below the pipeline's tolerance (Pmax) and decrease the number of nodes experiencing damaging negative pressures. This model effectively simulates hydraulic transients in dual-pipeline systems and provides a foundation for developing protective measures for pipeline operations.

Study on the influence of gas transmission characteristics of positive pressure beam tube system under graded pressurization

The positive pressure beam tube system addresses issues related to gas composition distortion, concentration variations, and long transmission delays observed in traditional negative pressure systems. It has increasingly become the primary system for early monitoring and warning of coal spontaneous combustion in goaf areas. Nevertheless, there remains a deficiency in comprehensive research concerning critical aspects like gas transmission characteristics and transmission lag time in the positive pressure beam tube system. This study aims to construct an experimental platform for the positive pressure beam tube monitoring system and systematically investigate how the choice of pressurization device, pipe length, pipe diameter, and driving pressure in the transmission pipeline affect gas transmission characteristics. The findings indicate that the most effective pressurization occurs under conditions of two-stage high positive pressure transport, with a driving gas pressure of 0.65 MPa. The optimal diameter for positive pressure gas transmission is 7 mm. Long-distance negative pressure pipelines result in decreased transmission efficiency, necessitating increased output pressure with the lengthening of positive pressure pipelines to maintain efficiency.

Refinement of Control Strategies for Wheel-Fan Systems in High-Speed Air-Floating Vehicles Operating in Atmospheric Pressure Pipelines

This study explored the optimization of control systems for atmospheric pipeline air-floating vehicles traveling at ground level by introducing a novel composite wheel-fan system that integrates both wheels and fans. To evaluate the control impedance, the system simulates road conditions like inclines, uneven surfaces, and obstacles by using fixed, random, and high torque settings. The hub motor of the wheel fan is managed through three distinct algorithms: PID, fuzzy PID, and the backpropagation neural network (BP). Each algorithm’s control strategy is outlined, and tracking experiments were conducted across straight, circular, and curved trajectories. Analysis of these experiments supports a hybrid control approach: initiating with fuzzy PID, employing the PID algorithm on straight paths, and utilizing the BP neural network for sinusoidal and circular paths. The adaptive capacity of the BP neural network suggests its potential to eventually supplant the PID algorithm in straight path scenarios over extended testing and operation, ensuring improved control performance.

Study on the Installation Quality and Ecological Environment Evaluation of Pressure Pipeline

In order to further strengthen the safety supervision of pressure pipelines and improve their environmental affinity, this paper focuses on the research of pressure pipelines conveying flammable, explosive, toxic and other media, and describes their quality management methods. Combined with practical application experience, the safety management system of pressure pipeline is established based on the safety technical specification and the latest version of ISO9001-2015 quality management system standard. The monitoring system designed in this paper is mainly composed of fiber grating surface strain sensor, fiber grating demodulator, LabVIEW computer software and GSM communication module. The surface strain of the measured object is detected by the fiber grating surface strain sensor. The fiber grating demodulator is connected to demodulate the central reflection wavelength of the fiber grating. Then the wavelength information of the sensor is collected by the computer software LabVIEW system and input to the computer for analysis and processing. The real-time monitoring function of the monitoring system is verified by experiments. The real-time data information of the sensor and the change trend of the whole strain can be read from the monitoring system.

Predictive plasticity unveiled: XFEM modeling of cyclic failure in pressurized straight pipelines under three-point bending

This study presents an innovative numerical approach for predicting pressurized welded pipelines’ cyclic behavior and failure mechanisms under complex loading conditions. Focusing on X52 steel pipelines subjected to internal pressure and three-point bending, we investigate the interplay between structural integrity, weld joint positioning, and boundary conditions. Our methodology integrates advanced finite element analysis with a sophisticated material model capturing isotropic and kinematic hardening. The constitutive behavior is calibrated using the Voce model, accurately representing the material’s cyclic response. We employ the von Mises yield criterion to characterize the multiaxial stress state within the pipeline. A key innovation is our application of the eXtended Finite Element Method (XFEM) coupled with the calibrated hardening model, enabling high-fidelity simulation of crack initiation and propagation. Our model’s predictive capabilities are rigorously validated against experimental data, demonstrating excellent agreement across various loading scenarios. Through comprehensive parametric studies, we elucidate the critical influences of internal pressure, end-fixation conditions, and weld joint locations on the pipeline’s structural response. Force-displacement hysteresis curves reveal complex, nonlinear behaviors significantly impacting fatigue life and failure modes. This research advances the understanding of cyclic plasticity and fatigue in welded pressurized pipelines, providing a robust computational framework for predicting long-term performance. The insights gained have far-reaching implications for enhancing critical energy-transportation infrastructure’s safety, reliability, and longevity, potentially informing future design criteria and regulatory guidelines.

Research on Hydraulic Characteristics of Water Leakage Phenomenon of Waterproof Hammer Air Valve in Water Supply Pressure Pipeline Based on Sustainable Utilization of Water Resources in Irrigation Areas

To investigate the causes of water leakage in the waterproof hammer air valve and its impact on sustainable water resource management, the DN100 waterproof hammer air valve was taken as the research object. By using the overset grid solution method of ANSYS Fluent 2021 R1 software, the flow field simulation of the waterproof hammer air valve was carried out. The transient action during the ascent phase of the key structural component floating ball, and the velocity and pressure distribution of the flow field inside the air valve are analyzed. The results showed that by giving different inlet flow velocities, the normal flow velocity range for the floating ball to float up was below 35 m/s and above 50 m/s. When the inlet flow velocity was between 35 m/s and 50 m/s, the growth rate of the pressure difference above and below the floating ball increased from 1.48% to 5.79% and then decreased to 0.4%. The floating ball would not be able to float up due to excessive outlet pressure above, which would cause the DN100 waterproof hammer air valve to leak water and fail to provide water hammer protection. When the inlet flow rate is 5 m/s, the velocity and pressure inside the valve body increase with time during the upward movement of the floating ball inside the waterproof hammer air valve and tend to stabilize at 400 ms. Through the generated pressure and velocity cloud maps, it can be observed that the location of maximum pressure is at the bottom of the buoy, directly below the floating ball, and at the narrow channels on both sides of the outflow domain. The location of the maximum velocity is at the small inlet of the bottom of the buoy. When the inlet speed of the valve is constant, a large amount of water flow is blocked by the floating ball, reducing the flow velocity and forming partial backflow below the floating ball, with an obvious vortex phenomenon. A small portion of the water flow passes through the air valve at a high velocity from both ends of the channel, and the water flow below the floating ball is in an extremely unstable state under the impact of high-speed water flow, resulting in a large gradient of water flow velocity passing through the valve. The research results not only help to improve the operational efficiency of water resource management systems but also reduce unnecessary water resource waste, thereby supporting the goal of sustainable water resource management.

Hydrogen and Natural Gas in Pipeline Networks: A Comparative Energy Analysis

Abstract In this study, a Simscape model for the transmission and distribution pipeline network of natural gas, hydrogen blended into natural gas and pure hydrogen, is developed. The transmission consists of a 250 km pipelines with a diameter of 48 in and two gas compression stations. The distribution network serves six end users. Two simulations are conducted for each gas: the first maintaining equal operational pressure in the transmission pipeline, while the second ensuring equal energy content at the final users by modifying the operational pressure. A comparative energy analysis is carried out to assess the gas mass flow rate, the thermal power delivered, the mechanical power required by compressors and the pressure losses along the pipeline.

Mechanical Properties and Microstructural Characteristics of Steel Pipes after Long-Time Hydrogen Exposure

There are three possibilities to transport hydrogen by high pressure pipeline (i) blending hydrogen into the existing natural gas pipeline system, (ii) after checking the integrity, using the natural gas transporting pipeline system to transport hydrogen, (iii) building a new pipeline system to transport pure hydrogen. In all three cases should be known the behaviour of the pipe material and its welded joints influenced under high pressure hydrogen. For this aim pipeline sections made of P355NH base material were investigated without and with hydrogen exposure, where the exposure time was 41 days. Gas metal arc welding and hybrid tungsten arc welding / gas metal arc welding were applied for preparation of the girth weld joints. Tensile, three point bending and hardness tests, furthermore microstructural investigations were performed both on base materials and girth welds of the pipeline sections. The testing results were analysed and compared with each other (base material vs. welded joints, without exposure vs. with exposure) and with limit values can be found in the literature. Conclusions were drawn on the behaviour of the investigated pipe material and its welded joints.

Data augmentation using SMOTE technique: Application for prediction of burst pressure of hydrocarbons pipeline using supervised machine learning models

Accurate burst pressure prediction is critical for ensuring oil and gas pipeline safety, guiding maintenance decisions, and lowering costs and risks. Traditional methods have limitations, including high experimental costs, conservative empirical models, and computationally expensive numerical algorithms. Machine learning (ML) models have supplanted traditional methods in recent years. However, small and imbalanced datasets are the big challenge to build a ML model that can generate more accurate results. Moreover, the lack of generalization in ML models trained on a dataset of pipelines with specific material grids prevents them from producing superior results on other pipeline types. First, FEA was used to make a dataset. Then, a new way to improve machine learning (ML) model generalization for burst pressure prediction is suggested: combine publicly available datasets of different pipeline specifications. In this combined dataset, some pipelines have a higher number of data samples, and some have fewer, which causes a class imbalance issue. The Synthetic Minority Oversampling Technique (SMOTE) technique was applied to address the issue of class imbalance. The performance of various ML models, Extra Trees (ET), Extreme Gradient Boosting (XGBR), Random Forest (RF), Light Gradient Boosting Machine (LGBM), and Decision Tree (DT), was evaluated to validate the model's prediction and generalization on pipelines of various material grids. Results show that all the selected ML models produced high R-squared, i.e., >0.95, on balanced data compared to the imbalance dataset. These results show that SMOTE-based augmentation is a beneficial way to fix dataset imbalance and make ML models better at predicting burst pressure in oil and gas pipelines.

Real-Time Analysis and Digital Twin Modeling for CFD-Based Air Valve Control During Filling Procedures

Air exchange in pressurized water pipelines is an essential but complex aspect of pipeline modeling and operation. Implementing effective air management strategies can yield numerous benefits, enhancing the system’s energy efficiency, reliability, and safety. This paper comprehensively evaluates an irregular profile pipeline filling procedure involving air-release through an air valve. The analysis includes real-time data tests and numerical simulations using Computational Fluid Dynamics (CFD). A Digital Twin model was proposed and applied to filling maneuvers in water installations. In particular, this research considers an often-overlooked aspect, such as filling a pipe with an irregular profile rather than a simple straight pipe. CFD simulations have proven to capture the main features of the transient event, which are suitable for tracking the air-water interface, the unsteady water flow, and the evolution of the trapped air pocket. Thus, they provide thorough and reliable information for real-time operational processes in the industry, focusing on the filling pressure and geometry of the air-valve hydraulic system. Additionally, this study provides details regarding the application of an efficient Digital Twin CFD approach, demonstrating its feasibility in optimizing the filling procedure in pipes with irregular profiles.

Consistency analysis of burst pressure in corroded pipelines

Abstract Due to the influence of the working environment and transport medium, corrosion defects inevitably occur on the inner and outer walls of natural gas pipelines. Scholars often studied the influence of internal and external corrosion defects on pipe burst pressure based on finite element method and experiment. However, it is not clear whether internal corrosion defects and external corrosion defects are consistent in burst pressure of pipelines. For this reason, this paper establishes the internal and external corrosion defect model of the pipe. Then, the burst pressures of pipelines with internal corrosion defects are compared with that with external corrosion defects. Finally, a burst pressure equation is proposed for the pipelines with internal corrosion defects and external corrosion defects. It was found that the burst pressure of the natural gas pipeline with internal and external corrosion defects was consistent. It provides a new idea for the establishment of a unified model to predict the burst pressure of corroded pipelines.

Numerical study of swirl core-annular flow and factors influencing pressure drop in vertical pipelines for oil-water two-phase flow

As oil field production progresses, the water content of the produced fluid increases and wax deposits form on the pipe wall as the crude oil is transported vertically through the pipeline. This causes the cross-sectional area of the pipeline to decrease, the flow resistance to increase and the pipeline pressure to decrease. As a result, production from oil wells declines and extraction costs rise. Therefore, in the current study, a vortex structure is utilized to generate a vertical core-annular flow for oil production and transportation in high-water-content oil wells. This study uses computational fluid dynamics (CFD) software to investigate the influence of various oil properties on the oil phase distribution and pressure drop in core-annular flow in vertical pipes. The findings demonstrate that the ring-forming effect of the core-annular flow increases with larger oil droplet sizes and lower oil phase densities, while it becomes weaker with higher inlet oil phase volume fraction and lower inlet velocities. As the size and density of the oil droplets grow and decrease, respectively, the pressure drop reduces. On the other hand, the pressure drop increases with higher inlet oil phase volume fraction and viscosity. When the oil droplet size is greater than 0.2 mm, the density is less than 850 kg/m3, the oil phase volume fraction is less than 30% and the inlet velocity is greater than 1 m/s, the annular flow works better. When the inlet oil phase volume fraction is above 30%, and the ring formation effect decreases significantly. The utilization of swirl core-annular fluid significantly mitigates the pressure drop in pipelines compared to pure oil transport downhole, rendering it highly suitable for conveying crude oil in high-water-content oil wells.

Characteristics of Gas–Liquid Two-Phase flow in rectangular narrow slits with varying cross sections driven by large pressure drop

Pressure pipelines and vessels inevitably contain some defects. Under the most unfavorable load combinations, these defects may gradually develop into through-wall cracks. High-pressure subcooled fluid leaks through these cracks, and two-phase gas–liquid flow often occurs within the cracks. In this study, natural through-wall cracks were replaced with narrow rectangular slits with varying cross sections. Experiments were conducted to investigate the variation patterns of gas–liquid two-phase leakage flow rates and pressure drops. The study focused on four types of rectangular narrow slits with varying cross sections, a width of 28 mm, a length of 80 mm, and a gap gradually ranging from 0.134 to 0.334 mm. The liquid-phase mass flow rate ranged from 150 to 700 kg/h, whereas the gas-phase mass flow rate varied from 0 to 20 kg/h. A one-dimensional homogeneous flow model was established by coupling two-phase velocity of speed calculations. This calibrated model was then used to predict pressure drops and flow parameters for gas–liquid two-phase flow in narrow rectangular slits with varying cross sections. The experimental data were analyzed to determine the two-phase leakage characteristics of different test pieces. The results show that the inlet–outlet pressure drop and flow quality are key factors affecting the two-phase leakage flow rate. The frictional pressure drop constitutes a major part of the total pressure drop along the flow path in different test pieces. Compared with the acceleration pressure drop in the expanding slit, that in the constricting slit is higher, with an increase of approximately 32 %. Among several commonly used empirical formulas for calculating two-phase viscosity, the McAdams and Dukler empirical correlations were found to be less suitable for high-velocity two-phase flows. In contrast, the Cicchitti empirical correlation provides better predictions, with a mean absolute deviation (MAD) and mean relative deviation (MRD) of no more than 8 %. The viscosity of the gas-phase medium affects the two-phase flow characteristics in narrow slits, which should be considered in practical engineering applications.

Research on Automatic Pipe Cleaning Technology for Natural Gas Medium and Low Pressure Pipelines

Abstract As the number of low-production and low-efficiency wells in Chang Qing gas field increases gradually, and the problems of pipeline liquid accumulation, freezing plugging and leakage due to production with liquid are worsening, in view of the low efficiency of manual analysis of abnormal pipeline status, the difficulty of timely detection of potential problems and the labor intensity of manual blockage clearing operation, we study an automatic pipeline clearing technology applicable to medium- and low-pressure gas pipelines in the gas field, which mainly includes pipeline operation status analysis and early warning system and automatic pipeline clearing device. An analysis and warning algorithm module is proposed to analyze, warn and locate the frozen plugging point based on pipeline pressure, differential pressure and flow parameters in real time. A low and medium pressure balling device is designed to achieve the goals of intelligent control, pressure isolation balling and safe operation through mechanical structure design, automatic control system and safety protection system. The device and system are applied in the well field at the end of 1 and 3# trunk pipelines of Shen Mu Gas Field Station 7, which verifies the feasibility, accuracy and stability of the technology. Based on the joint operation of the pipeline analysis and warning system and the automatic pipeline clearing device, it is able to meet the remote intelligent pipeline clearing operation and pipeline maintenance tasks in the process of gas gathering and transmission in the gas field.

Signals denoising of leakage pressure in water supply pipelines using an improved wavelet filter algorithm

Abstract Accurate identification of leakage pressure signal is crucial for leakage detection and location of water supply pipelines. However, there is a lot of noise signals in the negative pressure waves generated during leakage accidents, making it difficult to identify leakage signals, and thus seriously affecting the accuracy of leakage detection. Therefore, in this study, we carried out leakage test of water transmission pipeline on our self-built test platform for transient flow with long-distance water transmission pipeline (pipeline length is 160 m, and diameter is 100 mm), and obtained the transient leakage pressure signals under various flow rates (15–55 m3/h). An improved wavelet filtering algorithm was proposed to filter the leakage pressure signal by optimizing the calculation of decomposition layers and the threshold processing strategy, and then compared with the traditional wavelet filtering method. The results show that the improved algorithm can denoise the leakage signals effectively, and the signal-to-noise ratio (SNR), mean square error (MSE) and mean absolute percentage error (MAPE) are all superior to those of the traditional wavelet algorithm. The results can provide support for leakage detection and location of water supply pipeline systems.

Research on the Internal Flow Properties of the Bending Pipeline Based on the CFD

Abstract Pipeline connection is the main connection of hydraulic parts. For the study of pipe diameter, turning Angle and the turning radius of pipe, the influence law of the internal flow characteristics. this paper adopts CFD 3D simulation technology to explore the influence law of 5 kinds of bending radius, 6 kinds of bending Angle and 4 kinds of pipe diameter on the pressure loss of the pipeline. The results show that there are pressure difference and velocity difference in the inner wall and the outer wall of the bend, due to the impact of the fluid inertia force on the bend, when the fluid flows in the bend. As bending radius and pipe diameter increases, the pressure difference and speed difference of the inner and outer walls at the turning point of the pipeline are reduced, the local pressure loss at the bending is reduced, the internal pressure loss of the pipeline is reduced, and the flow is more uniform. With the increase of bending angle, the pressure difference and velocity difference of the inner and outer walls of the pipeline bending increase, the local pressure loss increases, and the overall pipeline pressure loss increases. The research results of this paper can provide some reference for pipeline hydraulic design and optimization.

MEMS Fabry-Perot sensor for accurate high pressure measurement up to 10 MPa.

Microelectromechanical system (MEMS) Fabry-Perot fiber-integrated pressure sensor exhibits a compact size, intrinsic safety, and high precision measurement. Here, a MEMS Fabry-Perot interferometer sensor is presented. The sensor is fabricated using a standard microfabrication process with a uniformity of 80%. The sensor enables a pressure measurement range of 0-10 MPa with a full-scale nonlinearity error of 1.44% and a repeatability error of 2.14%. A limit of detection of 1.74 kPa and a pressure resolution of 0.017% are achieved. The comparative experiment is conducted to verify the wavelength tracking method is more robust than cavity length demodulation method in this configuration. Moreover, the temperature drift is alleviated by combining a fiber Bragg grating sensor for compensation in a range of -35-88 °C, which is reduced by 15 times to 2.88 ppm/°C. The proposed sensor has wide potential applications, such as downhole environments and petroleum pipeline pressure monitoring.

Dual channel visible graph convolutional neural network for microleakage monitoring of pipeline weld homalographic cracks

When using a single sensor to monitor early microleakage of nuclear power pressure pipeline leakage, there are problems such as low monitoring accuracy and poor early warning reliability due to the limitations of the monitoring range and weak difference between the leakage signals. To address these challenges, this paper proposes a dual channel visible graph convolutional neural network (DCV-GCN). Firstly, the acoustic emission time-series data of each channel are truncated and divided, and the significant frequency bands are selected based on the envelope spectrum. On this basis, the sequence group is averaged to obtain the graph structure sequence. Then, the limited penetrable visibility (LPV) graph construction algorithm is used to calculate the adjacency matrix, and the important nodes is reserved according to the eigenvector centrality. Furthermore, the inverse ratio of the distance from the sensor in each single channel to the center of the crack is used as the fusion weight, and the adjacency matrices are merged after normalization to transform the construction of the graph structure dataset. Finally, the dataset is input into the graph convolutional neural network, and the effectiveness of the method is verified by carefully designing three homalographic cracks. The results show that the proposed method can effectively extract the distinguishing features with similar frequency components and similar leakage rates, and the recognition accuracy of different leakage states can reach 98.56 %. In addition, through ablation experiments and different parameter strategy settings, the operating mechanism is explained, which can provide a reference for monitoring and analysis by industrial technicians.

Determination of the required degree of surface perforation of collecting drainage pipelines

The operational characteristics of a collecting pressure pipeline, where the flow enters through holes and slots along its length in a turbulent mode, and a pressure drainage pipeline, where liquid enters through the side walls in a filtration mode, are investigated. Based on a comparison of analytical dependencies used to describe the flow entry laws into the pipelines in each case, relatively simple and practical calculation formulas have been derived to determine the required degree of the side walls perforation of the drainage pipeline. These formulas ensure that the desired water flow rate is achieved in the collector. The degree of perforation S in this work is defined as the ratio of the area of the perforation holes (slots) in the side walls of the drainage pipeline to the total area of its side surface. In the analysis of the pipelines considered, parameter A is used, which comprehensively accounts for both the design and filtration characteristics of the drainage pipelines. Relevant analytical dependencies and a graph for determining this parameter are presented. A series of calculations have been performed using the proposed formulas to determine the degree of perforation for these pipelines. It is shown that, in general, the magnitude of the perforation degree is influenced by both the structural characteristics of the pipeline itself and the filtration properties of the surrounding soil and the surface of the drainage pipes.

Water hammer protection of one-way surge tanks considering the effect of check valve

ABSTRACT One-way surge tanks are commonly employed as water hammer protection devices. However, the action process of the check valve is often disregarded in the design of protective measure. In this study, a one-way surge tank model incorporating a check valve was developed based on the method of characteristics. The check valve action process and different installation positions for one-way surge tanks were investigated based on an actual water supply project. The results show that, compared with the existing one-way surge tank mathematical model, the pipeline pressure calculated by the new model is smaller and the water replenishment is slower, which means that there is a safety risk based on the calculation results of the existing model. As the opening process of the check valve slows down, the pipeline minimum pressure is reduced. When the valve opening rate reaches 0.5 s, negative pressure appears in the pipeline. In addition, for undulated terrain with two obvious high points, when the first one-way surge tank is installed at the node behind the pump, the second one should be installed at the highest point to ensure that the pipeline pressure is greater than 0 m.