Pipe Cross-sectional Area Research Articles

Evaluating the performance of water distribution network deterioration using customer-oriented performance indices

ABSTRACT Water distribution networks (WDNs) are an essential urban infrastructure, with their performance directly influencing societal well-being. Our study applied to a real network model that employs a 24-h simulation with 1-h time steps and evaluates the impact of leaks and loss in the pipe cross-sectional area on WDN hydraulic performance as experienced by end users. Adhering to a UK utility's 20-m head pressure requirement as the water main benchmark, we present two new customer-oriented performance indices (CPIs) centred on network reliability and pressure deficit severity. The new CPIs adeptly quantify network performance degradation due to pipe deterioration. This degradation translates directly to a poor customer experience, highlighting the potential for these CPIs to pinpoint areas of the network where performance levels are compromised. Furthermore, the CPIs identify individual pipes within the network where defects would severely impact network performance and the sets of pipes which, when simultaneously experiencing defects, would lead to a more severe loss in network performance. Results show that the CPIs capture relatively small performance declines and identify sensitive pipes impacting network performance, providing insights for optimised inspection and maintenance intervention to provide better customer service.

Analisis Penentuan Kedalaman Penanaman Pipa Flowline Untuk Mencegah Terjadinya Upheaval Buckling

A force inside a pipe drains fluid from wells producing oil and natural gas. When the power works exceed the pipe's maximum resistance limit, it will cause deformation in the line. This research aimed to evaluate the height of the trench to determine the threshold of tremendous friction force working on the pipe to withstand the axial force, which can cause upheaval buckling. The method used is the calculation of stress analysis. The line of 12 inches measured its style and voltage was planted in the trench with l.5 meters high and 3 meters wide and the soil density of 14.70kN/m3. The data used in the calculation were the design pressure, the outside diameter of the pipe, the minimum melting point of the line, the design factor, the factor of pipe connections, the derating factor, the modulus young, the thermal expansion coefficient, the pipe installation temperature, the maximum operating temperature, the Poisson ratio, the internal pipe pressure, the sectional area of the inner pipe, the pipe cross-sectional area, the depth of pipe planting, the trench width, the value of pipe nondimension, and the soil density of flowline area. The analysis result indicated that the friction force is 356,025.71N/m, and the axial force is 44,927.35N/m. These results showed that the friction force working on the pipe could withstand the axial force working. The cost of making the trench can still be decreased by reducing the height of the track to l m. The excellent friction force in the channel with a size of lm is 252,501.92N/m, where the value is still more significant than the axial force. In conclusion, the friction force working with the trench lm high can still hold the axial force working on the pipe.

Detection of faults in subsea pipelines by flow monitoring with regression supervised machine learning

This study investigates the relationship between pressure change, velocity change, and temperature of crude oil through a pipeline and presents a method of using a regression supervised machine learning (ML) algorithm to detect faults. A representative dataset of crude oil flow is generated by computational fluid dynamics (CFD) and used to train the algorithm to develop a model of fluid behavior under normal pipeline operations over a range of typical flow rates and temperatures. CFD data are then collected under several simulated fault conditions: leaks of 10% and 20%, and a 50% restriction to flow, by nominal pipe cross-sectional area. This study demonstrates that the ML algorithm can be trained to model the system under normal conditions, thereby successfully recognizing a fault condition as non-conforming and indicative of a statistically significant change in pipeline operation. It is further able to identify the fault type based on the pattern observed in the new data. It is shown that ML may be a safe, low-cost, and accurate method of monitoring a subsea pipeline for optimal performance and fault detection without the need to introduce special equipment to a subsea pipeline network, providing an avenue for enhanced process safety and protection of ocean environments. This paper demonstrates that the application of ML to the monitoring of pipeline networks could provide valuable contributions to the industry in terms of safety, cost, and environmental protection.

Numerical study on the heat performance of enhanced coaxial borehole heat exchanger and double U borehole heat exchanger

• The BHEs model considering the multilayer properties and groundwater flow. • An enhanced coaxial model with intermittently laid spiral ring fins was proposed. • The heat transfer performance of the vertical BHEs was evaluated. • The influence level of different factors on heat transfer performance was analyzed. • The influence of groundwater flow on the ground temperature field was analyzed. Borehole heat exchangers (BHEs) are widely used in various building air conditioning and heating systems. It has always been the unremitting pursuit of researchers to provide solutions for energy conservation by improving the heat transfer efficiency of BHE. In this work, comprehensively considering groundwater seepage in the surrounding rock and soil and the difference of heat transfer performance between various layers of rock and soil, three-dimensional geometric models of double-U BHE and enhanced coaxial BHE with intermittently laid spiral ring fins were established. The established model was verified by the drilling, geothermal, thermal response data collected through filed tests and the actual operating data of the system. The heat transfer performance and influencing factors of the two BHEs models under different working conditions were simulated by improving and replacing the double-U BHE model by means of equivalent buried pipe cross-sectional area. The results showed that the linear meter heat transfer of the enhanced coaxial BHE was significantly better than the linear meter heat transfer of the equivalent U BHE. The average linear meter heat transfer of the enhanced coaxial BHE can reach 1.46 times and 1.45 times of the equivalent U BHE under winter and summer working conditions, respectively. Finally, the results of the sensitivity analysis of single factor showed that the inlet temperature/inlet fluid heating power is the most significant impact on the heat transfer performance, followed by the inlet flow rate, and the hydraulic gradient of groundwater seepage has the least impact. The results obtained can provide a new type of the buried pipe structure that can be used as a reference for improving the heat transfer performance of BHEs in the simulation and experiment conditions.

Effect of Abrupt Changes in the Cross-Sectional Area of a Pipe on Flame Propagation Characteristics of CH4/Air Mixtures.

To study the flame propagation characteristics of methane/air premixed gas in the pipeline with a sudden change of the pipe cross-sectional area, six kinds of customized pipes are used to study the methane/air premixed gas with a concentration of 9.5%. The results show that when the initial smooth flame front encounters an abrupt change in the cross-sectional area, the flame front becomes disordered and a turbulent flame is formed. A greater change in the cross-sectional area results in more severe flame turbulence. Compared with larger cross-section pipes set at the ignition end and downstream end, when the large cross-sectional area pipe is set in the middle of the pipe, the flame propagation process receives the secondary mutation induction effect of the abrupt cross section and the turbulence effect is stronger. The maximum propagation velocity and pressure are observed in configuration with the larger pipe in the middle of the pipe network. Moreover, when the cross-sectional area of this larger pipe increases, the flame is more substantially influenced by longitudinal expansion, the maximum propagation velocity and maximum overpressure increase accordingly, and the pressure oscillations are more obvious.

Approach for Near-Real-Time Pipe Burst Detection, Localization, and Quantification with Low Data Transmission and Sampling Rates

The purpose of the paper is to present an approach for pipe burst detection, localization, and cross-sectional area quantification based on the changes in the discrete harmonic spectrogram and analysis of damping of fluid transients. The amplitude of each resonance response of the burst-induced transient wave in each analyzed time window in the spectrogram is damped differently because of the presence of the burst. A pressure signal processing algorithm for pipe burst detection and estimation has been developed by the authors to explore this specific type of analysis, in conjunction with a predefined gap between each window. Because the window gap can be set to be equal to the data transmission and sampling rates in the analysis to detect and estimate the burst, it can be applied during real-time data monitoring. Unlike other hydraulic transient-based detection methods, the proposed algorithm only requires the Nyquist frequency of the third resonance response as the data transmission and sampling rates, which are significantly lower than the same quantities in commonly used data acquisition systems. The algorithm has been verified both numerically and experimentally.

Interfacial area transport for bubbly-to-slug transition flows in small diameter pipes

This study aims to experimentally investigate the two-group interfacial area transport in small diameter pipes. Experimental data focusing on the bubbly to slug transition regime, namely one-group to two-group transport region, are collected in a 12.7 mm vertical pipe under adiabatic, air-water conditions. The result shows the intergroup transfer in the small diameter pipe can be drastic, especially under low superficial liquid velocities. The cause of this phenomenon is mainly due to the large relative bubble size comparing to the pipe cross-sectional area. The wake entrainment effect could be enhanced by the small spherical bubbles that are acting like cap or slug bubbles in a medium-size pipe. Based on the experimental observation, a throughout analysis of the dependence of the drastic intergroup transfer is provided in this study. The models predicting the initiation of drastic intergroup transfer in small diameter pipes in terms of the bubble diameter and the void fraction are developed. These models are compared with the two-phase data among the different pipe sizes and the results show a good agreement. These newly developed models are applied to the IATE wake entrainment model by developing a transition function analogous to the sigmoid function. With the transition function, the revised IATE model is given the new ability on predicting the drastic intergroup transfer phenomenon.

Laminar flow through corrugated pipes: comparison of exact and approximate solutions

Exact flows are calculated for an infinite set of pipe cross-sections, each with variable corrugations, ranging from angular to smooth as a parameter varies. The results are compared with three ‘rules of thumb’ which give general but approximate formulae for the rate of flow through a pipe of given cross-sectional shape. These are (i) the Saint-Venant formula, in which the flow is related to the area and the polar moment J about the centroid of the pipe cross-section; (ii) the Aissen approximation, in which the flow is approximated in terms of the pipe cross-sectional area A and the diameters of the inscribed and circumscribed circles; and (iii) the area–perimeter or hydraulic radius approximation of various authors, which states that for a given pressure gradient and fluid viscosity the total flow rate through a pipe of given cross-section is proportional to A3/P2 where P is the perimeter length of a pipe section normal to the pipe axis. Formulae are given for the flows and pipe properties for corrugation number ranging from three to infinity.

Discharge coefficient equation to calculate the leakage from pipe networks

With the increasing of urbanization, water distribution networks play an important role in human life and the effective use of water resources. Therefore, studies have been made for the optimization of water distribution networks in some fields such as pressure management and leakage control. In this context, the discharge coefficient, which is one of the components of the hydraulic calculations, is a very significant parameter in calculating the losses. In this study, a new equation has been proposed to calculate the discharge coefficient. Computer simulations were done by using ANSYS Fluent and discharge coefficient values were determined for round holes. Firstly, the model validated with theoretical Toricelli (orifice) equation and then, the model was run for number of scenarios according to various internal pressure and hole areas. The model results were formulated by means of regression equations. To satisfy the dimensional homogeneity, the ratio of the hole area to the pipe cross-sectional area, area ratio (r), and the ratio of the internal pressure to the external pressure, pressure ratio (p), were used. In this study, easy to use discharge coefficient equation was proposed to calculate the leakage losses in water distribution networks. With the help of this equation, the discharge coefficient can be calculated precisely for different pressure values and leakage areas rather thantaken as a constant value. Thus, the calculation of the leakage flow rate will be more accurate. Furthermore, it is concluded that the dicharge coefficient varies between 0.65 and 0.72. There is also inverse realtionship between discharge coefficient and pressure and discharge coefficient and leakage area.

Numerical analysis of fluid hammer in helical pipes considering non-Newtonian fluids

This study focuses on a 3D CFD analysis of the laminar fast transient flow of non-Newtonian fluids through helical pipes. Classical simulations of fluid hammer do not deal with the pipeline helicity and non-Newtonian characteristics of the fluid, while the present work addresses those features. To this end, ANSYS FLUENT is used for simulation of the 3D domain and the power-law model is employed to accommodate the non-Newtonian behavior of the fluid. Effects of the pipe wall elasticity and compressibility of the working fluid are taken into account through a modified bulk modulus elasticity of the fluid using a UDF code. The results of the three-dimensional numerical analysis followed herein demonstrate good agreement with the available experimental data, and they show that non-Newtonian properties of the fluid significantly influence the pressure head response, velocity and shear stress profiles, and also the strength of the formed secondary flows. At the first stage of the fluid hammer, where the maximum deviation arises, the magnitude of the wall shear stress at the pipe midpoint for the shear-thinning and shear thickening fluids are respectively 67.7% lower and 200% higher than the Newtonian fluid. Furthermore, the average magnitude of the axial vorticity over the upper half of the pipe cross-section area for the shear-thinning and shear-thickening fluids are respectively 65.5% lower and 111.7% upper than the Newtonian case.

A Self-Powered and Low Pressure Loss Gas Flowmeter Based on Fluid-Elastic Flutter Driven Triboelectric Nanogenerator.

A self-powered and low pressure loss gas flowmeter is presently proposed and developed based on a membrane’s flutter driven triboelectric nanogenerator (TENG). Such a flowmeter, herein named “TENG flowmeter”, is made of a circular pipe in which two copper electrodes are symmetrically fixed and a nonconductive, thin membrane is placed in the middle plane of the pipe. When a gas flows through the pipe at a sufficiently high speed, the membrane will continuously oscillate between the two electrodes, generating a periodically fluctuating electric voltage whose frequency can be easily measured. As demonstrated experimentally, the fluctuation frequency (fF) relates linearly with the pipe flow mean velocity (Um), i.e., fF ∝ Um; therefore, the volume flow rate Q (=Um × A) = C1fF + C2, where C1 and C2 are experimental constants and A is the pipe cross-sectional area. That is, by the TENG flowmeter, the pipe flow rate Q can be obtained by measuring the frequency fF. Notably, the TENG flowmeter has several advantages over some commercial flowmeters (e.g., vortex flowmeter), such as considerable lower pressure loss, higher sensitiveness of the measured flow rate, and self-powering. In addition, the effects of membrane material and geometry as well as flow moisture on the flowmeter are investigated. Finally, the performance of the TENG flowmeter is demonstrated.

Heat Transfer and Entropy Generation in Concentric/Eccentric Double-Pipe Helical Heat Exchangers

Double-pipe helical heat exchangers are integral to contemporary mechanical refrigeration equipment. Modification of flow geometry has been widely adopted to enhance heat transfer performance of a heat exchanger. The objective of this study is to numerically investigate heat transfer and entropy generation in a double pipe helical heat exchanger with various cross-sections. A computational model for laminar convective heat transfer was developed and validated against the results from previously published literature. To capture entropy generation, the entropy balance equation for open system is adopted. Effect of inner pipe Dean number, inner pipe and annulus inlet mass flow rate ratio, eccentricity, and flow configuration (co-flow and counter-flow) were examined and discussed in light of computational results. To ensure fair comparison, the considered geometries have same inner pipe cross-section area, same annulus cross-section area, and same outer surface area of inner pipe. The results suggest that square cross-section offers best performance in term of heat transfer, pressure drop and entropy generation. In addition, concentric configuration is more appropriate for low flow rate application while eccentric outer configuration is more suitable for high flow rate application.

Theoretical investigation of the influence of pipe diameter and exit channel width in welded plate heat exchanger on heat exchanger performance

In this study, to examine the effects of the changes in the inlet and outlet pipe diameters and exit channel width on the performance of a welded plate heat exchanger, a CFD (Computational Fluid Dynamics) analysis of the welded plate heat exchanger was carried out while changing the Rp-ch (ratio between the cross-section area of pipe and channel) and Rf-e (ratio between the end width of exit and front width of channel). The realizable k–e model with the non-equilibrium wall function was used. As a result, the heat exchange performance decreased slightly, but the pressure drop decreased significantly by a decrease in Rp − ch and an increase in Rf − e. In addition, the results of this study confirmed that a change in Rp − ch affects the pressure drop of inlet and outlet manifolds significantly, and a change in Rf − e affects the pressure drop of the channel and outlet manifold significantly.

Determination of Tile Drain Discharge under Variable Hydraulic Conditions

The aim of this study was an investigation of tile drain flow velocity under variable hydraulic conditions and of tile drain discharge using an ultrasonic flow meter. There is an essential variance between velocity values measured by an ultrasonic flow meter and reference values determined by a laboratory method. Differences result from specific measurement conditions, which appear in drainage pipe systems. The values of velocity measured by ultrasonic flow meters were higher than the reference values for three examined flow phases: Free, transient, and pressured flow. The discharge from a tile drain working on a partially filled up pipe in no-pressure conditions should be calculated by an adapted equation based on the California pipe method, whereas the discharge from a completely filled up drain pipe working over pressure should be calculated as a ratio between 0.428 times the measured velocity and the pipe cross-section area.

An experimental study on gas/liquid/solid three-phase flow in horizontal coalbed methane production wells

Coal particles caused by well drilling and completion, hydraulic fracturing, and formation pressure decreasing would migrate into the horizontal well carried by fracturing flow-back fluid, formation water and CBM, and then deposit on the low side of pipe leading to the decrease of cross section area of pipe for flow and even blocking of the pipe. The purpose of current research was to obtain the flow pattern while there was stationary solid particle bed on the low side of the pipe and an explicit equation to predict the height of solid particle bed was proposed. In this study, with the coal particle, water, and air as the solid, liquid, and gas phases respectively, gas/liquid/solid three-phase flow experiments in horizontal well were carried out and 4 crucial factors including different water flow rate, gas flow rate, coal particle size, and coal particle mass concentration were considered. Fluid's real apparent velocity was defined and used to analyze the distribution of flow pattern coordinate points. Results show that the flow pattern coordinate points determined by real gas apparent velocity and real water apparent velocity distribute near the flow pattern transition lines of Taitel and Dukler flow pattern map. Besides, coal particle size, water flow rate, and gas flow rate have obvious impact on the height of coal particle bed and the coal particle mass concentration has a negligible effect while the height of interface between gas layer and water layer is only dramatically affected by the gas flow rate. At last, an explicit equation for predicting the cross section area of coal particle bed based on the experimental data was proposed which is crucial to predict the flow pattern and calculate the pressure drop in horizontal well. The predicting cross section area of coal particle bed is in good agreement with the measured cross section area of coal particle bed and the average relative differences are 9.38% and 13.45% for stratified smooth flow and stratified wavy flow respectively. The equation is applicable for a range of coal particle size (8–30 mesh) and water apparent velocity (0.025–0.123 m/s).

Optimization of the Amount of Gas Moles Determination through Boyle’s Law and Gay-Lussac’s Law Experiments

<p class="Abstract">Boyle’s Law describes the inverse relationship between absolute pressure and air volume, if the temperature is constant in a closed system. Gay Lussac’s Law states that the pressure of a gas mass is directly proportional to the absolute temperature of the gas, when the volume is held constant. The macroscopic quantity associated with both laws includes the number of moles of gas. The purpose of the study is to calculate the number of moles of gas through Boyle’s Law and Gay Lussac’s Law experiments. The experimental results were confirmed by calculating the number of moles theoretically, so that it can be concluded that the experimental device settings which the closest to the theoretical results. The Boyle’s Law experimental results with a pipe cross-sectional area of 54.08 mm<sup>2</sup>, at a temperature of 295 K obtained 4.67 x 10<sup>-4</sup> moles, its relative uncertainty is 7.60%, at a temperature of 299.1 K obtained 3.97 x 10- 4 moles, the relative uncertainty value is 0.51%, and at a temperature of 299.5 K obtained 5.20 x 10<sup>-4</sup> moles, the relative uncertainty value is 12.56%. The average relative uncertainty value of the three experiments is 6.89%. The results of the Gay Lussac’s Law experiment, at a gas volume of 0.578 x 10<sup>-3</sup> m<sup>3</sup>, obtained the number of moles in a row of 1.38 x 10<sup>-2</sup> moles, 1.83 x 10<sup>-2</sup> moles and 1.33x 10<sup>-2</sup> moles, theoretical calculation of 2.14 x 10<sup>-2</sup> moles. The average value of the relative uncertainty of the three experiments is 24.3%. Based on these results, it can be concluded that the results of calculating the number of moles through Boyle’s Law experiments are closest to theoretical calculations.</p>

Non-deposition self-cleansing design criteria for drainage systems

Self-cleansing is a substantial aspect of the drainage systems in which it is desired to minimize the sediment deposition that can cause channel blockage and surcharge early overflows. In the conventional self-cleansing design criteria of drainage systems, a single value of velocity or shear stress is used based on experience. In the recent decades rather than using a single value, non-deposition design concept has been further modified to develop self-cleansing models based on higher number of parameters considering flow, fluid, sediment and channel characteristics. However, non-deposition self-cleansing models have been mostly developed for circular channels, and none of the models considers yet the effect of channel cross-section although some models take into account the pipe diameter, hydraulic radius and cross-section area as independent variables. In this study, a self-cleansing model considering the effect of cross-section by a shape factor available in the literature is developed to determine the non-deposition particle Froude number for bed load sediment transport. The model is developed using experimental data of circular, rectangular and U-shape channel cross-sections from the literature; and data of trapezoidal channel cross-section from experiments carried out in this study. For validation of the model, data collected in this study is used together with four different sources of data taken from the literature. Validation of the model for each cross-section data shows its wide range applicability in terms of different channel cross-sections.

The influence of hematite particle shape on stratification in pipe flow

This paper discusses the influence of hematite particle shape factor, through the sphericity function, on the concentration distributions of solids over the cross sectional area of the pipe for the hydraulic transportation of hematite industrial mineral concentrates. The results are depicted by figures of solids distribution along three sectors of the pipe cross sectional area of the pipe and the sphericity function of particles from each section were evaluated using the permeametry method. A recirculating pipeline testing loop with a transparent section and pipe diameter (D) of 50mm, with a special gutter device installed at the discharge of the test loop, was employed. The hematite mineral concentrate used is composed exclusively of coarse particles clustered in two particle size (d) ranges: 0.210mm<d<0.297mm and 0.105mm<d<0.149mm. The results of solids distribution profiles indicated that the coarser particle class yielded a more heterogeneous concentration profile over the cross sectional area flowing at the critical deposition velocity (VC). The slurry stratification inside the pipe was influenced by the particle shape factor evaluated by the sphericity function according to each pipe section. The higher the particle sphericity the more these particles were found at the bottom of the pipe. It was also observed that <6% of the bulk particles flowed in the top section of the pipe (0.8D from the bottom to the top) for any given condition.

Parametric Study of Perforated Pipe Underdrains Surrounded by Loose Aggregate

AbstractA detailed computational parametric study of a perforated pipe underdrain surrounded by loose aggregate has been conducted. Several controlling geometric parameters (i.e., trench width, head, aggregate depth over the pipe, pipe wall perforation area per unit length of pipe, and the area of individual perforations) were considered and the variation of pipe discharge characteristics as a function of these parameters has been quantified. Results indicate that, for each combination of these parameters, there is a finite pipe length after which discharge does not increase with increasing pipe length. This pipe length depends on the pipe wall perforation area per unit length of pipe, pipe cross-sectional area, and losses associated with them. It was found that the effective pipe system discharge coefficient is independent of the channel width, aggregate depth, and head over the pipe for the range of parameters tested. The computational fluid dynamics (CFD) results were used to develop an equation for th...

Determining Seed Cotton Mass Flow Rateby Pressure Drop across a Blowbox

<abstract> <b><sc>Abstract. </sc></b>A seed cotton mass flow rate sensor would offer useful feedback for gin managers and provide a critical input for advanced process control systems. Several designs of seed cotton mass flow rate sensors have been evaluated in the laboratory, but none have found acceptance in commercial gins. The objectives of this research were to develop a system for predicting seed cotton mass flow rate based on the pressure drop measured across a blowbox; investigate the effect of pipe diameter, cultivar, moisture content, feed rate, and fan speed on this relationship; and provide recommendations for developing a prototype system for testing in commercial gins. A negative pressure pneumatic conveying system was constructed with a variable-speed feed control and fan. The inlet air velocity, blowbox pressure drop, temperature, and relative humidity were recorded during testing. A model was developed to predict the seed cotton mass flow rate based on the blowbox pressure drop, air velocity, air density, and pipe cross-sectional area. The model was calibrated by conveying a known mass of seed cotton through the system and integrating the model over this time. Mean absolute error in predicting seed cotton mass was 7.35%. Cultivar and moisture content had no effect on the model regression coefficients. Significant differences existed between the regression coefficients of different feed rates; however, these only occurred at mass flow ratios much larger than those achieved in commercial gins. The effect of fan speed was small and likely not practically significant. Measuring the pressure drop across a blowbox is a suitable basis for further development of a seed cotton mass flow rate sensor for commercial gins.