Selection of Water Transmission Method and Analysis of Pipe Network Zoning in Municipal Water Supply and Drainage Design

With the acceleration of urbanization,the demand for water supply and drainage pipe networks has increased significantly.In the planning of urban construction,it is necessary to optimize the design of the water supply and drainage system pipe network to effectively save energy while providing residents with more accessible water resources.Therefore,the municipal water supply and drainage system and the water transmission methods should be designed according to the geographical conditions of the city.In this paper,we mainly analyze the design of municipal water supply and drainage systems and the selection of water transmission methods.Besides,the optimization of the water supply and drainage network zoning process and pipe network maintenance is also discussed,so as to provide a reference for municipal water supply and drainage work.

Prediction of Load-Displacement Curve of Flexible Pipe Carcass Under Radial Compression Based on Residual Neural Network

The carcass layer of flexible pipe comprises a large-angle spiral structure with a complex interlocked stainless steel cross-section profile, which is mainly used to resist radial load. With the complex structure of the carcass layer, an equivalent simplified model is used to study the mechanical properties of the carcass layer. However, the current equivalent carcass model only considers the elastic deformation, and this simplification leads to huge errors in the calculation results. In this study, radial compression experiments were carried out to make the carcasses to undergo plastic deformation. Subsequently, a residual neural network based on the experimental data was established to predict the load-displacement curves of carcasses with different inner diameter in plastic states under radial compression.The established neural network model’s high precision was verified by experimental data, and the influence of the number of input variables on the accuracy of the neural network was discussed. The conclusion shows that the residual neural network model established based on the experimental data of the small-diameter carcass layer can predict the load-displacement curve of the large-diameter carcass layer in the plastic stage. With the decrease of input data, the prediction accuracy of residual network model in plasticity stage will decrease.

Computational Fluid Dynamics Approach for Predicting Pipeline Response to Various Blast Scenarios: A Numerical Modeling Study

Recent industrial explosions globally have intensified the focus in mechanical engineering on designing infras-tructure systems and networks capable of withstanding blast loading.Initially centered on high-profile facilities such as embassies and petrochemical plants,this concern now extends to a wider array of infrastructures and facilities.Engineers and scholars increasingly prioritize structural safety against explosions,particularly to prevent disproportionate collapse and damage to nearby structures.Urbanization has further amplified the reliance on oil and gas pipelines,making them vital for urban life and prime targets for terrorist activities.Consequently,there is a growing imperative for computational engineering solutions to tackle blast loading on pipelines and mitigate associated risks to avert disasters.In this study,an empty pipe model was successfully validated under contact blast conditions using Abaqus software,a powerful tool in mechanical engineering for simulating blast effects on buried pipelines.Employing a Eulerian-Lagrangian computational fluid dynamics approach,the investigation extended to above-surface and below-surface blasts at standoff distances of 25 and 50 mm.Material descriptions in the numerical model relied on Abaqus’default mechanical models.Comparative analysis revealed varying pipe performance,with deformation decreasing as explosion-to-pipe distance increased.The explosion’s location relative to the pipe surface notably influenced deformation levels,a key finding highlighted in the study.Moreover,quantitative findings indicated varying ratios of plastic dissipation energy(PDE)for different blast scenarios compared to the contact blast(P0).Specifically,P1(25 mm subsurface blast)and P2(50 mm subsurface blast)showed approximately 24.07%and 14.77%of P0’s PDE,respectively,while P3(25 mm above-surface blast)and P4(50 mm above-surface blast)exhibited lower PDE values,accounting for about 18.08%and 9.67%of P0’s PDE,respectively.Utilising energy-absorbing materials such as thin coatings of ultra-high-strength concrete,metallic foams,carbon fiber-reinforced polymer wraps,and others on the pipeline to effectively mitigate blast damage is recommended.This research contributes to the advancement of mechanical engineering by providing insights and solutions crucial for enhancing the resilience and safety of underground pipelines in the face of blast events.

Application of Dynamic Programming Method in Optimization of Water Distribution Pipe Network

With a water-supply network by dynamic programming. The minimal as an example, the network was optimized annual discounted costs were taken as an objective function and node pressure etc. as constraint conditions. The alternative pipe diameters were optimized as per enumeration method and the group allowing objective function with the least values would be the optimized one. It is proved the optimized pipe network reduced by 11.49% in terms of cost and the optimized ben- efits proved much significant.

Function chain neural network prediction on heat transfer performance of oscillating heat pipe based on grey relational analysis

As for the factors affecting the heat transfer performance of complex and nonlinear oscillating heat pipe (OHP),grey relational analysis (GRA) was used to deal with the relationship between heat transfer rate of a looped copper-water OHP and charging ratio,inner diameter,inclination angel,heat input,number of turns,and the main influencing factors were defined.Then,forecasting model was obtained by using main influencing factors (such as charging ratio,interior diameter,and inclination angel) as the inputs of function chain neural network.The results show that the relative average error between the predicted and actual value is 4%,which illustrates that the function chain neural network can be applied to predict the performance of OHP accurately.

Optimal operation of water distribution networks under local pipe failures

The optimal operation of water distribution networks under local pipe failures, such as water main breaks, was proposed. Based on a hydraulic analysis and a simulation of water distribution networks, a macroscopic model for a network under a local pipe failure was established by the statistical regression. After the operation objectives under a local pipe failure were determined, the optimal operation model was developed and solved by the genetic algorithm. The program was developed and examined by a city distribution network. The optimal operation alternative shows that the electricity cost is saved approximately 11%, the income of the water corporation is increased approximately 5%, and the pressure in the water distribution network is distributed evenly to ensure the network safe operation. Therefore, the proposed method for optimal operation under local pipe failure is feasible and cost-effective.

Basic Research on Key Techniques Related to Urban 3D Pipe Network Modeling

A new geometric modeling approach is introduced in this paper.First the principle of modeling of 3D pipe network is discussed in detail.Then the procedures of implementing pipe network visualization and system functions are presented.Last,several efficient methods for speeding up display of graphics are introduced.The new geometric modeling approach offers to people a new way to solve 3D visualization of complex urban pipe network.

Conflict detection in collaborative architectural pipe routing design based on constraint network

This paper analyzes conflict features in architecture pipe routing,and builds a pipe routing design conflict model by taking into account of discrete nominal internal diameter selection of pipes,material costs,and conflict solution sequence.Considering pipe routing as an assembling process,a conflict detection approach for pipe routing in collaborative architectural design is proposed based on an aforementioned model.Constraint network is used to describe the relationship among pipe routing design parameters and constraints;design conflicts are detected by matching designers' input and constraint network;and detected design conflicts are reordered according to the number of pipe parameters in conflicts.In order to support the collaborative requirement of pipe routing design,a prototype system using browser/server architecture is developed.An illustrative example of water pipe routing in a room is used to show the effectiveness and efficiency of the approach.

On the method of the automatic modeling in hydraulic pipe networks

In this paper the dynamic characteristics in pipes are analyzed with frequency method, and puts forward a simple and practical describing method. By establishing the model library beforehand, the modeling of the pipe net is completed automatically, and we can accurately calculate the impedance characteristics of the pipe network, achieve the reasonable configuration of the pipe network, so that to decrease the pressure pulsation.

Heat Transfer and Flow Analysis in Loop Heat Pipe with Multiple Evaporators Using Network Model

Thermal performance of a loop heat pipe with two evaporators and two condensers was examined using a lumped network model analysis. Thermosyphon-type vertical loop heat pipe and capillary-pump-type horizontal loop heat pipe were calculated by examining the change of heating rate of two evaporators. Calculation results showed that the vapor and liquid flow rates in the loop heat pipe and the thermal conductance of the heat pipe changed significantly depending on the distribution ratio of the heating rate of the multiple evaporators. The thermal performance of the vertical loop heat pipe with two evaporators was also examined and experimental results of flow direction and thermal conductance of the heat pipe agreed with the analytical results. The lumped network model analysis is therefore considered accurate and preferable for the practical design of a loop heat pipe with multiple evaporators.

Impact of the Condition of Drinking Water Supply Networks on the Quality of Water Intended for Consumption: The Case of the Network in the Commune of Daloa (Central West of Côte d’Ivoire)

The potability of drinking water depends not only on the source and the treatment system, but also on the quality of the waterworks. In fact, the quality of drinking water is considerably degraded by the dilapidated state and lack of maintenance of drinking water networks. In Côte d’Ivoire, the majority of drinking water networks in the various towns are ageing. In Daloa, despite the efforts made by the company in charge of water treatment and distribution to make the water drinkable, the water at consumers’ taps is often colored, has an unpleasant aftertaste and settles after collection. As a result, people are concerned about the potability of tap water, and some are turning to alternative sources of drinking water of unknown quality. In order to determine the factors responsible for the deterioration in water color and taste, as well as the sectors of the network most affected, a diagnosis of the network’s equipment was carried out. Water samples taken from the network were analyzed for color and turbidity. The diagnosis revealed that most of the equipment (suction pads, valves, drains and fire hydrants) is outdated and irregularly maintained. Analyses show that the water is more colored in cast-iron and PVC pipes than in asbestos cement pipes. Coloration values in the network range from 0 to 27 UVC for asbestos cement pipes, from 15 to 56 UCV for ductile iron pipes, and from 11 to 102 UCV for PVC pipes. On the over hand, turbidity values vary from 8.02 to 3.32 NTU for ductile cast iron pipes, 8.51 to 16.98 NTU for asbestos cement pipes and 0.9 to 6.98 NTU for PVC pipes. Old cast-iron pipes release ferric ions on contact with water, degrading their color. Old cast-iron pipes release ferric ions into the water, degrading its color. The high color values observed in the vicinity of drains are thought to be due to irregular maintenance of the network. In fact, after network maintenance, a reduction rate ranging from 2% to 73% is observed for turbidity, while for color, the rate varies from 5% to 72%. In short, the network’s obsolescence and irregular maintenance contribute significantly to the deterioration of water quality.

PIPE Networks选用英飞朗DTN-X平台在关岛和悉尼间搭建100G海底网络

Marketwire2012年9月10日，加利福尼亚州桑尼维尔讯一TPGTelecomLimited旗下的全资子公司PIPENetworksPtyLimited（PIPE）与全球领先的数字光纤通信系统提供商英飞朗（Infinera）（纳斯达克股票代码：INFN）目前宣布，PIPE的海底光缆系统PPC-1选用了英飞朗的DTN-X平台。PIPE是澳大利亚的主要电信运营商之一。

A Linear Programming Model for Seabed Oil-Gas Pipe Network

This paper analyzes the pipe network system of oil-gas collection and transportation for offshore oilfield development. A '0-1' integer linear programming model is constructed to optimize the investment of seabed pipe network. The mathematical model is solved by the spanning tree method of graph theory and network analysis. All spanning trees of a network graph compose all the feasible solutions of the mathematical model. The optimal solution of the model is the spanning tree with the minimum cost among all spanning trees. This method can be used to optimize the seabed pipe network system and give a minimum cost plan for the development of offshore marginal oilfield groups.

宁夏回族自治区碳捕集、利用与封存源汇匹配与集群部署

“双碳”(碳达峰、碳中和)战略背景下,碳捕集、利用与封存技术(CCUS)是实现化石能源大规模低碳化利用的关键技术之一。近年,CCUS技术呈现出规模化和集群化发展趋势,而科学、合理的源汇匹配是CCUS集群部署工程选址的重要依据,能够建立高效CO_(2)输运管网、降低减排成本。宁夏是国家能源安全战略布局的重要保障基地,能源结构偏煤、工业结构偏重特征明显,面临着巨大的碳减排压力。针对宁夏CCUS集群部署的源汇匹配问题,调研评估了宁夏工业碳排放源特征和地质碳汇潜力,构建了CCUS源汇匹配模型,在充分考虑源汇性质、捕集-输运-封存成本、CO_(2)运输距离、区域地理条件、土地利用类型、人口密度等因素基础上,应用改进的节约里程法和基于地理信息系统(GIS)的最低成本路径优化法,结合ArcGIS平台和优化求解软件,获得了宁夏CCUS源汇匹配优化和应用方案,并提出宁夏CCUS集群部署建议。结果表明,截止2021年,宁夏工业碳排放源107个,碳排放总量2.26亿t/a,以化工(含自备电厂)和电力行业碳排放为主。宁夏主要封存地质体包括深部咸水层、深部不可开采煤层和油气藏,CO_(2)理论地质封存容量151.55亿t,以深部咸水层封存潜力最大。宁夏CCUS源汇匹配效果较好,在源汇直接相连的情况下,区内年排放量10万t以上的大型工业排放源CCUS集群部署(30 a规划期)总成本约2.45万亿元,并以捕集成本为主,占比83.65%,单位减排成本402.32元/t,共需建设CO_(2)运输管道2 459 km;改进的节约里程法和基于GIS的最低成本路径优化法可大幅降低CCUS集群部署成本,优化后CCUS单位减排成本降至381.76元/t,节约管道建设里程938 km。宁夏应聚焦电力、化工等“两高”(高耗能、高排放)行业,在以宁东能源化工基地为重点的北部、东部地区超前应用CCUS技术,打造宁东能源化工基地、银川—吴忠、石嘴山、中卫和固原5个CCUS特色集群,构建宁夏特色的工程化CCUS全流程技术模式。

基于高低温分区热管网络的高轨通信卫星散热能力提升方法

针对我国高轨通信卫星不断提升的散热需求,提出采用基于高低温分区热管网络的热设计方法。在分析热管网络散热能力的基础上,进行设备分区布局设计、分区热管网络散热面设计和分区热管网络布局设计。该方法可在保证卫星仪器设备工作温度、不降低热设计可靠性、不增加分系统重量及功率需求的前提下,将卫星散热能力提升15%~20%。文章还结合近些年通信卫星研制中的经验和教训,归纳给出高低温分区热管网络设计中的注意事项,以期为相关工程设计提供有效指导。

知识-数据驱动的沉管隧道接头安全状态分析方法——以港珠澳大桥海底沉管隧道为例

为解决沉管隧道接头安全状态不断变化且难以直接感知的技术难点,以港珠澳大桥海底沉管隧道为工程背景,通过分析既有监测数据,总结管节接头的变形模式,揭示管节接头张合量与结构温度的强相关性,明确潮位变化对接头剪切变形的显著影响。在此基础上提出一种基于知识-数据驱动的沉管隧道接头变形快速推演方法,通过建立沉管隧道精细化有限元模型,开展海量典型变形模式下的沉管隧道结构力学行为分析,构建沉管隧道变形服役行为数据集;利用BP神经网络,建立基于仿真接头服役行为特征的沉管隧道接头全断面变形推演模型,实现基于有限实测数据的接头全断面变形快速重构。该方法在港珠澳大桥海底沉管隧道的现场管养中得到成功应用。以2023年台风“苏拉”为例,基于台风登陆过程中接头的局部位移实测数据,推演接头剪力键及止水带关键点位处管节接头的变形情况。结果表明,该沉管隧道接头系统整体受台风影响较小。

基于POA-BP的TP2管材自由弯曲成形结果预测

将壁厚减薄率和椭圆率作为管材自由弯曲成形结果的评价指标,选取弯曲模与管材间隙值、弯曲模圆角半径值、管材弯曲变形区长度、导向机构圆角半径值、导向机构与管材间隙值作为影响因子。利用数值模拟方法对管材自由弯曲成形结果的评价指标和影响因子建立样本库,并随机选取6组作为测试样本,其余的作为训练样本,结合BP神经网络和鹈鹕优化算法对预测模型进行训练,构建POA-BP神经网络预测模型对管材自由弯曲成形结果进行预测。结果表明,POA-BP预测模型的壁厚减薄率和椭圆率的最大预测误差不超过2%,故POA-BP预测模型能够有效预测管材成形结果。

无阴极保护燃气管道腐蚀危害的表征参量及规律

对某燃气公司2016~2020年间泄漏燃气管道的管地电位分布情况进行了统计分析,同时开展了现场腐蚀检查片埋设试验,获得了检查片腐蚀速率数据及对应的检查片通电电位、电流密度、通断电电位差、环境电阻率、地表电位梯度等5个参量,通过数据分析得出各参量与腐蚀速率的相关性及相关规律。结果表明,电流密度与管道腐蚀速率的相关性最好,皮尔逊系数高达0.95,在没有检查片的条件下,可以采用管地电位指标对管道的腐蚀风险进行评判。

NH_(4)H_(2)PO_(4)-KHCO_(3)混合粉体对管网甲烷爆炸的抑制特性

在自行搭建的管网实验系统中,将常用于抑制甲烷爆炸的碳酸氢钾KHCO_(3)与磷酸二氢铵NH_(4)H_(2)PO_(4)进行不同比例的混合。选取5种不同的粉体配比,对比单一粉体以及各抑爆工况下各测点的爆炸峰值压力、火焰峰值速度和火焰峰值温度等爆炸特征参数,获得抑制管网甲烷爆炸的最佳工况,并阐述了抑爆机理。结果表明:混合粉体对管网甲烷爆炸的抑制性能优于单一粉体;KHCO_(3)与NH_(4)H_(2)PO_(4)都易受热分解;其中,KHCO_(3)可以在相对较低的温度下迅速完成热解过程,从而吸收更多的反应热,抑爆性能优于NH_(4)H_(2)PO_(4)粉体;混合粉体中,抑爆效果随着KHCO3含量的增加显著提高。在5种混合比例中,当KHCO_(3)与NH_(4)H_(2)PO_(4)质量比为2.0:1.0时,抑爆效果最佳。KHCO_(3)与NH_(4)H_(2)PO_(4)表现出良好的爆炸抑制效果,研究所得结论可为抑制甲烷爆炸研究提供参考。

基于数据驱动的桁架优化设计方法

针对目前圆管带式输送机桁架有限元分析和优化方法中存在的过程繁琐以及仿真速度、目标性差等问题,提出了利用数据驱动方法来优化改进圆管带式输送机桁架的方法,从而简化有限元分析和优化过程,减少分析和优化时间。首先明确桁架的加载方式及荷载值,运用控制变量法、数值模拟法及工程经验选取桁架最终构型并进行有限元分析。其次以实际仿真值作为输入值,建立基于数据驱动的优化网络模型。最终在不超过最大应力的条件下,利用优化网络模型获得桁架质量的寻优结果。结果表明,基于数据驱动的优化方法在圆管带式输送机桁架优化上具有快速性和准确性的优势,能够满足工程需要。