New design solutions for low-power energy production in water pipe systems

This study is the result of ongoing research for a European Union 7th Framework Program Project regarding energy converters for very low heads, and aims to analyze optimization of new cost-effective hydraulic turbine designs for possible implementation in water supply systems （WSSs） or in other pressurized water pipe infrastructures, such as irrigation, wastewater, or drainage systems. A new methodology is presented based on a theoretical, technical and economic analysis. Viability studies focused on small power values for different pipe systems were investigated. Detailed analyses of alternative typical volumetric energy converters were conducted on the basis of mathematical and physical fundamentals as well as computational fluid dynamics （CFD） associated with the interaction between the flow conditions and the system operation. Important constraints （e.g., size, stability, efficiency, and continuous steady flow conditions） can be identified and a search for alternative rotary yolumetric converters is being conducted. As promising cost-effective solutions for the coming years, adapted rotor-dynamic turbomachines and non-conventional axial propeller devices were analyzed based on the basic principles of pumps operating as turbines, as well as through an extensive comparison between simulations and experimental tests.

TRANSIENT RESPONSE OF A VALVE CONTROL HYDRAULIC SYSTEM WITHLONG PIPES

The simulation model of a valve control hydraulic system with long pipe isestablished in Simulink4.0, and then the step responses of the systems with difference pipeparameters are investigated by simulation. Simulation results show that the long pipes will slowdown the step response of system and make it fluctuate periodically. The results of simulationconform to the results of experiment on the whole, which proves the mathematic model is correct.

Dynamic Analysis of Deep-Ocean Mining Pipe System by Discrete Element Method

The dynamic analysis of a pipe system is one of the most crucial problems for the entire mining system. A discrete element method （DEM） is proposed for the analysis of a deep-ocean mining pipe system, including the lift pipe, pump, buffer and flexible hose. By the discrete element method, the pipe is divided into some rigid elements that are linked by flexible connectors. First, two examples representing static analysis and dynamic analysis respectively are given to show that the DEM model is feasible. Then the three-dimensional DEM model is used for dynamic analysis of the mining pipe system. The dynamic motions of the entire mining pipe system under different work conditions are discussed. Some suggestions are made for the actual operation of deep-ocean mining systems.

SELECTION OF OBJECTIVE FUNCTIONS AND APPLICATION OF GENETIC ALGORITHMS IN DAMPING DESIGN OF PIPE SYSTEM

The vibration failure of pipe system of aeroengine seriously influences the safety of aircraft.Its damping design is determined by the selection of the design target,method and their feasibility.Five objective functions for the vibration design of a pipeline or pipe system are introduced,namely,the frequency,amplitude,transfer ratio,curvature and deformation energy as options for the optimization process.The genetic algorithms(GA)are adopted as the opti- mization method,in which the selection of the adaptive genetic operators and the method of implementation of the GA process are crucial.The optimization procedure for all the above ob- jective functions is carried out using GA on the basis of finite element software-MSC/NASTRAN. The optimal solutions of these functions and the stress distribution on the structure are calculated and compared through an example,and their characteristics are analyzed.Finally we put forward two new objective functions,curvature and deformation energy for pipe system optimization.The calculations show that using the curvature as the objective function can reflect the case of minimal stress,and the optimization results using the deformation energy represent lesser and more uni- form stress distribution.The calculation results and process showed that the genetic algorithms can effectively implement damping design of engine pipelines and satisfy the efficient engineering design requirement.

Integrity Assessment of Pipe System in a Full-Scale Membrane Water Treatment Plant

The pipe system roles as a main bridge between membrane modules and pumps in membrane water treatment plants. Membrane operation modes generally consist of filtration and backwash processes in a normal mode, a pressure decay test as an integrity test and a chemical circulation through pipe system in a cleaning mode. Thus factors effecting on membrane performance should be sufficiently considered before design and operation. This study evaluated flow analysis for vibration diagnostic and evaluation of the fatigue lifetime in the microfiltration system applied for a drinking water treatment plant. Vibration of main membrane pipelines was measured to identify the source of vibration. Also natural frequency and fluid dynamics was calculated by computational fluid dynamics. It showed that maximum magnitude frequencies were at 12 Hz and 22 Hz, respectively at water and air pipeline during filtration and backwash. Backwash process caused mainly vibration on the backwash water pipe. The calculated frequency from analysis of frequency response and CFD was in a good agreement with the measured frequency. Fatigue analysis showed that pipelines were getting little damage caused by vibration. Fatigue lifetime was predicted more than 15 years under the operation condition of daily filtration, and more than 27 years under the operation condition of a daily backwash mode, resulting in minor damage on the pipe lifetime.

Burning Cave-Pipe Coil-Kang Coupled Heating System Research

Nowadays,people still rely on traditional heating methods in rural areas of northern China,such as Kang(bed-stoves) and burning caves in cold winter.Field measurements of indoor environment were carried out in several rural houses with burning-cave-coil-Kang coupling heating system in northern China.The results show that this system is able to realize the graded use of internal energy of burning cave.The temperature of supply pipe water ranged from 30 ℃ to 50 ℃ which met the demands in 74.7% of time.The surface temperature of Kang maintained at above 25 ℃.Compared with traditional burning cave,using burning-cave-coil-Kang coupled with heating system has a higher thermal efficiency of 48.9%,which is 8.32% higher than the traditional one.

Mechanics of a Grip System of Three-Key-Board Hydraulic Tongs Developed for Offshore Oil Pipe Lines

This paper carries out the analysis of mechanics of a grip system of three-key-board hydraulic tongs developed for offshore oil pipe lines which has been successfully used in oil fields in China. The main improvement of this system is that a lever frame structure is used in the structural design, which reduces greatly the stresses of the major components of the oil pipe tongs. Theoretical analysis and numerical calculation based on thirteen basic equations developed Show that the teeth board of the tongs is not easy to slip as frequently happens to other systems and is of higher reliability.

STUDY ON USING SERIAL PIPE TO IMPROVE THE DYNAMIC RESPONSE OF ELECTRO－HYDRAULIC SPEED CONTROL SYSTEM

The mathematical models of electro-hydraulic speed control system using series of pipesis presented. The principle of pipe effection on dynamics of the system is developed. Computersimulation and physical experiment are also carried out. The experimental results show that a rightchoosing of serial pipe for electro-hydraulic system enables the dynamic response of the system tobe improved effectively.

关于压力管道及压力管道元件监管方式的总结与思考

根据现行法规对压力管道、压力管道元件的监管方式进行总结,重点分析了对工厂化预制管段、流量计(壳体)、撬装式承压设备系统和进口压力管道元件的监管。

长直管道预混气体爆燃波系演化过程研究

为减少工业场所可燃气体生产、运输和储存过程中气体爆炸事故的发生,利用自主搭建的200 mm×200 mm×35 m方形管道和直径为90 mm、长度为10 m的圆形管道,在相同的初始条件下,运用体积分数为9.5%的甲烷/空气预混气体开展爆炸试验,结合压力、火焰传感器对其进行研究。结果表明:2种不同尺度、不同截面的管道中波系演化过程是相同的,点火后火焰由层流向湍流转变,火焰加速导致压缩波相互追赶,最终形成强激波;速度在2种长直管道中的变化趋势相同,都经历了加速—减速—再加速—再减速的过程,方管和圆管中火焰速度最大分别达到69和35.7 m/s,第一道压缩波经壁面反射后压力上升至117%和114%;当反射波与火焰阵面耦合作用时,方管和圆管中火焰速度分别降至73%和93%;体积分数相同的条件下,2种长直管道中第一道压缩波的最大压力值相近,方管中为65.45 kPa,圆管中为67.09 kPa。

中深层地埋管热泵供热系统运行特性实测研究

通过大量工程实测研究,总结了中深层地埋管热泵供热技术的运行特性。中深层地埋管具有出水温度高、取热功率大、长期运行稳定的特点,为热泵系统提供了高品位的低温热源,以提升其运行性能;同时中深层地埋管自身存在间歇蓄热特性,能很好地满足建筑供热需求变化与柔性用能;无级变频热泵机组更适合与中深层地埋管匹配运行,节能减排效果显著;热源侧水系统具有小流量、大扬程,且阻力随着流量变化而大幅度变化的特性。研究结果可为提升该技术的供热性能提供关键指导。

强涌潮区管袋围堰施工安全风险仿真研究

强涌潮区的水域环境复杂多变,这极大增加了管袋围堰施工安全管理的难度。为确定强涌潮区管袋围堰施工从清基到维护阶段的安全管控重点,首先利用系统理论过程分析法(STPA)对施工安全风险因素进行定性分析,从人员、物资、管理、技术、环境5个维度构建了强涌潮区管袋围堰施工安全风险指标体系;然后建立系统动力学(SD)演化模型,并运用网络层次分析法(ANP)确定各指标权重;最后结合工程实例进行模拟仿真。结果表明:随着工程推进以及对安全投入的逐步增加,管袋围堰施工安全风险水平呈现出先大幅上升,后逐步下降,最终趋于平缓的趋势;人员、物资是清基和吹填期影响施工安全的主要因素,而在排水和维护期,环境、管理是主要影响因素;人员、管理和环境这三因素对安全投入变化更为敏感。建议在施工过程中重视不同阶段之间的管控重点差异,及时转换管理策略并采取针对性措施以有效降低施工安全风险。

变电站变压器监测系统的研究

电力变电站是电力系统的核心组成部分,而变压器作为关键的电力设备,其运行状态对电网的稳定性和可靠性起着至关重要的作用。然而,变压器故障可能导致电力系统的严重问题,不仅影响电力供应的连续性,还可能对环境造成损害。因此,建立一套有效的监测系统,能够实时检测变压器的运行状况并预测潜在故障,对维护电力系统的安全和可靠性至关重要。研究首先利用Petri网建立传统变电站变压器监测系统的模型,然后分析其中存在的问题,通过增加相关库所和变迁,重新设计一个优化后的监测系统模型,这一模型允许更快速的故障诊断和更精准的运行状态监测,从而提高电力系统的可靠性。最后,在PIPE仿真软件中对优化后的模型进行实验仿真,验证此优化后模型的可靠性和有效性。

基于虚拟现实的立管横焊机器人辅助焊接工艺设计与实现

焊接工艺参数的选择对焊接质量有重要影响。针对立管J型铺设窄坡口横焊熔池下淌特性,提出基于横焊焊道厚度及热输入恒定策略的焊接工艺参数匹配算法。基于Unity3D开发平台和工艺参数匹配算法,通过C#开发了立管横焊CAPP模块,扩展了虚拟现实人机交互系统的功能模块;开展立管横焊计算机辅助焊接工艺实验,焊后焊缝成形良好,无焊接缺陷。实验结果表明:CAPP模块可有效获取匹配的焊接工艺参数,能缩短焊接工艺开发周期,降低工艺开发成本,有效提升系统的智能化水平。

双碳背景下场段设计与综合应用——以南宁地铁5号线那洪车辆基地为例

地铁场段作为城市大宗用地、大宗能源消耗的大户,其在落实碳达峰、碳中和政策方面具有十分重要的作用。为探究场段响应并实施双碳政策的技术路径,进一步厘清双碳战略下场段可实施的具体技术措施及效果,以南宁地铁5号线那洪车辆基地为例,以区域规划诉求、环境融合、智慧智能发展为导向,采取统筹规划、提前策划等手段,全过程采用双碳设计解决措施实现场段低碳节能。通过分析场段,可采取绿色生态体系建立、节能减排设计、智能化设计3个方面实现场段低碳节能。运营实践后表明,实施系列化双碳解决措施后,场段在节水、节电、节省人工方面效果显著,减少折合碳排放约23%,为后续城市轨道交通低碳节能提供有效参考。

集输系统双管掺水工艺节能优化运行研究

某区块采用双管掺水集油工艺流程,由于现场无法判断掺水参数与现场工况的关系,导致回液温度远高于原油凝点,造成能源浪费,超出了经济运行成本区间。针对上述问题,利用Pipesim软件实现工艺建模,分析了掺水参数与工艺热能损失、井口回压、回液温度、工艺压能损失及能耗损失占比等参数的定量关系,得到了符合现场调控的一般性规律,并通过建立目标函数和约束条件,利用萤火虫算法实现了掺水比和掺水温度的自动调控。结果表明:掺水温度建议不超过75℃,掺水比不宜过高,现场调控应采用先调节掺水温度再调节掺水比的操作方式;随着掺水比和掺水温度的增加,单井运行费用存在最低值;经算法优化后,不同单井掺水比和掺水温度均有不同程度下降,预计每天可节约运行费用0.5万元~1万元。

压力容器及容器-管道系统的安定载荷计算方法对比

针对压力容器及容器-管道系统的安定载荷计算,介绍了循环弹塑性分析法、下限安定定理法和双极限载荷法3种求解安定载荷方法的原理和流程。基于这3种方法,具体计算了机械载荷下厚壁圆筒和标准椭圆封头中心接管的安定载荷,以及热载荷下标准椭圆封头中心管系整体模型的安定载荷,并对比分析了3种方法的优缺点。结果表明,循环弹塑性分析法能较准确地反映结构的实际承载能力,但求解复杂、工作量最大;双极限载荷法和下限安定定理法相对于循环弹塑性分析法的最大误差均小于5%,且偏保守,双极限载荷法的计算量最小。综合考虑计算精度和工作量,在工程设计中可采用双极限载荷法;对于计算精度要求较高、周围弹性材料对最大应力点的约束能力较弱的情况,建议采用循环弹塑性分析法。

长江流域平原河网地区合流制排水系统溢流污染特征研究

在平原河网地区丹金溧漕河金坛段选取3个典型合流制溢流排口及管道检查井进行溢流污染监测,分析溢流水质水量变化。以合流制管道沉积物为试验材料进行冲刷模拟试验,探究沉积物冲刷规律。结果表明,累积降雨量≥2 mm就会产生溢流现象;溢流水量变化主要受降雨等级、降雨强度及居民用水量影响,且溢流量峰值较降雨强度峰值滞后;溢流污染物浓度与前期干旱天数、排口性质、降雨等级和降雨强度有直接联系,其变化基本均呈先上升后下降趋势,且无论哪种降雨等级溢流口在产生径流后约20~30 min后污染物浓度会较高。沉积物对溢流污染贡献占比较大,管道冲刷过程中沉积颗粒物呈阶段交替式运动,各污染指标在降雨形成径流一段时间后出现峰值。

基于混合和谐搜索算法的自压滴灌田间管网多目标优化设计

为了综合考虑管网投资和水压分布,合理进行管网布置和管径选择,以满足管网的经济性和可靠性,使自压滴灌管网系统达到投资最低和灌水均匀度最高的目的。以管网投资最低(管网经济性)和节点富余水头均值最小(管网可靠性)为目标,建立了自压滴灌“梳子”形和“丰字”形田间管网系统的多目标优化数学模型,提出了混合和谐搜索算法求解多目标优化模型的方法和步骤。以新疆某自压滴灌工程为例,采用该方法对其田间管网系统进行优化,优化方案的管网总投资为47.63万元,与原设计方案相比降低了9.86%;管网节点富余水头均值为8.87 m,与原设计方案相比降低了28.37%。该优化设计方法得到的优化结果,不仅节省投资明显,而且节点富余水头均值显著减小,说明管网系统的压力偏差小,灌水的均匀度显著提高。优化结果表明,混合和谐搜索算法收敛速度快,计算精度高,在自压滴灌管网的多目标优化设计中具有很好的应用价值。