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.

Development and prospect of downhole monitoring and data transmission technology for separated zone water injection

This article outlines the development of downhole monitoring and data transmission technology for separated zone water injection in China.According to the development stages,the principles,operation processes,adaptability and application status of traditional downhole data acquisition method,cable communications and testing technology,cable-controlled downhole parameter real-time monitoring communication method and downhole wireless communication technology are introduced in detail.Problems and challenges of existing technologies in downhole monitoring and data transmission technology are pointed out.According to the production requirement,the future development direction of the downhole monitoring and data transmission technology for separated zone water injection is proposed.For the large number of wells adopting cable measuring and adjustment technology,the key is to realize the digitalization of downhole plug.For the key monitoring wells,cable-controlled communication technology needs to be improved,and downhole monitoring and data transmission technology based on composite coiled tubing needs to be developed to make the operation more convenient and reliable.For large-scale application in oil fields,downhole wireless communication technology should be developed to realize automation of measurement and adjustment.In line with ground mobile communication network,a digital communication network covering the control center,water distribution station and oil reservoir should be built quickly to provide technical support for the digitization of reservoir development.

Investigating the structural effect of electrospun nano-fibrous polymeric films on water vapor transmission

Electrospun polymers have many applications in the industry.However, the structure of these polymers has been less widely considered by researchers.In this work, the structural effect of electrospun and casted films of polyacrylonitrile(PAN) and polyvinylidene fluoride(PVDF) polymers on water vapor transmission were investigated.Sorption of water vapor was measured at 35, 60 and 80 ℃ and different relative humidities.The diffusion coefficients were calculated based on mass changes of the polymer sample.The water vapor transmission rate(WVTR) was also measured at 35 ℃ and 90% relative humidity.The results indicated that electrospun nano-fibrous polymers(ESNPs) absorb much higher water vapor compared to non-porous casted polymers.The interaction of water molecules with mentioned polymers was investigated based on Flory-Huggins theory.The Flory-Huggins interaction parameter of electrospun films was less than casted films, suggesting much better interaction of water molecules with electrospun films.It was also found that electrospun films have anomalous kinetic behavior and do not obey the Fickian diffusion model.Finally, it was revealed that ESNPs show less resistance to water vapor transmission and they are good candidates for the applications of water vapor separation using membranes.

Research Progress on Contamination Status,Transmission and Treatment Technology of Antibiotics in Water Environment

With the wide application of antibiotics in medicine and industry fields as well as the improvement of water quality detection technology,more and more reports show that antibiotics and antibiotic resistance genes(AGRs)were detected in various drinking water sources.The existence of these pollutants in water environment posed a great threat to human health.In this paper,the pollution status of antibiotics and transmission routes of antibiotic genes were introduced,and the characteristics and shortcomings of antibiotic treatment technology both at home and abroad were analyzed.Finally,suggestions and prospects for future antibiotic treatment technology were put forward.

Inter-Basin Water Transfer Projects and Climate Change: The Role of Allocation Protocols in Economic Efficiency of the Project. Case Study: Dez to Qomrood Inter-Basin Water Transmission Project (Iran)

Nowadays, there is a growing emphasis on Inter-basin water transfer projects as costly activities with ambiguous effects on environment, society and economy. Since the concept of climate change was in its embryonic phase before 1990’s, the majority of these projects planned before that period have not considered the effect of long term variation of water resources. In all of these numerous operational and under-construction projects, an intelligent selection of the best water transmission protocol, can help the governments to optimize their expenditures on these projects ,and also can help water resources managers to face climate change effects wisely. In this paper as a case study, Dez to Qomrood inter-basin water transfer project is considered to evaluate the efficiency of three different protocols in long term. The effect of climate change has been forecasted via a wide range of GCMs (Global Circulation Model) in order to calculate the change of flow in the basin's area with different climate scenarios. After these calculation, a water allocation model has been used to evaluate which of these three water transmission protocols (Proportional Allocation (PA), Fix Upstream allocation (FU), and Fix Downstream allocation (FD)) is the most efficient logic switch economically in a framework including both upstream and downstream stakeholders. As the final result, it can be inferred that Fix Downstream allocation (FD) protocol can supply more population especially with urban water for a fix expense and also is the most adapted protocol with future global change, at least in the first round of sustainability assessment.

Economical and Environmental Effects of Pressure Reducer Valve Substituting by Small Hydro Power-Plants in Gravity Water Transmission Pipelines in Iran

In this work, historical background of power generation by small hydro-power plants across the world and specially across the Iran with emphasis on small hydro-power plant utilization as recovery turbine in water transmission pipeline have been attended firstly, and then, three water transmission pipelines from Chah-nemie to Zahedan city, Shirindare dam to Bojnord city and Mokhtaran desert to Birjand city in Iran have been studied as case study samples. According to the sample pipeline characteristics and pipeline topography, reachable energy have been estimated; in the next step, pay attending to reachable energy, initial investment cost, total benefit of operating period, benefit to cost ratio and other economical parameters for small hydro-power plants in case study pipelines have been presented and generated power cost of the same amount via other resources compared to the hydro-power cost. At the end, in agreement with environmental advantages of small hydro-power plants, the methods of generated power utilization, proper solution for optimization of reachable energy in water transmission pipeline and substitution of pressure reducing valve by small hydro-power plant in the pipelines as a major solution for energy recovering in water pipelines have been proposed.

Analysis on Transmission Heat Loss in Hot Water System of Residential Building

Based on the data of China Statistical Yearbooks, the current situation and development trend of the energy consumption of residential hot-water was discussed in this paper. Two hundred and sixty eight apartments were surveyed on the installation and operation situations of residential water heaters in five cities. Based on survey data, the proportion of pipeline heat loss was calculated in the energy consumption of a shower/bath. The influence factors of heat loss in residential hot-water pipeline network were discussed, and the measures were suggested for reducing the transport heat loss. The statistics and analysis conclusion have directive significance to reducing the transport heat loss.

A review of research progress in air-to-water sound transmission

International and domestic research progress in theory and experiment and applications of the air-to-water sound transmission are presented in this paper. Four classical numerical methods of calculating the underwater sound field gener- ated by an airborne source, i.e., the ray theory, the wave solution, the normal-mode theory and the wavenumber integration approach, are introduced. Effects of two special conditions, i.e., the moving airborne source or medium and the rough air-water interface, on the air-to-water sound transmission are reviewed. In experimental studies, the depth and range distributions of the underwater sound field created by different kinds of airborne sources in near-field and far-field, the longitudinal horizontal correlation of underwater sound field and application methods for inverse problems are reviewed.

基于实际工况的燃料电池水气传输及相变规律研究

利用CFD软件建立二维多相质子交换膜燃料电池单电池模型,对不同工况下质子交换膜燃料电池内部水气传输及相变过程进行仿真。在试验验证及元无关性验证的基础上,分析起步工况、加速工况、急停工况下的质子交换膜燃料电池内部状态变化。研究结果表明:当电流密度为1500 mA/cm^(2)时,质子交换膜燃料电池功率密度达到最大值654.9 mW/cm^(2);起步工况下,质子交换膜燃料电池内部反应会在达到额定功率10 s后逐渐达到平衡;加速工况下,三次方加速模式的最低液态水饱和度界面、水-气相界面的持续时间最长;急停工况下,质子交换膜燃料电池的突然停机会使得其仍保持与停机前相近的状态。

长距离输水泵站中空气罐参数敏感度分析及正交优化设计

为了探讨长距离输水泵站中空气罐的优化设计方法,以西北某长距离输水工程为例,以泵站水击最大正压水头和最小负压水头作为优化目标,以初始气体压力、高度直径比、连接管直径、进口阻力系数和出口阻力系数为优化变量,基于正交优化设计方法和KYPipe软件,采用极差分析法获得空气罐各参数对于水击最大正压水头和最小负压水头的影响,同时对得到的结果进行排序,比较并找到最优参数组合.结果表明:初始气体压力、连接管直径和出口阻力系数等因素对于水击最大正压水头和最小负压水头的影响程度较大,其中初始气体压力是最敏感的参数,对于最大正压水头和最小负压水头的影响程度最大;经过比较发现最优方案的参数组合为初始气体压力水头50 m、高度直径比4、连接管直径250 mm、进口阻力系数10、出口阻力系数5;相比原始方案,优化方案使泵站的水击最大正压水头降低4.98%、最小负压水头升高64.00%.

基于固-气-液耦合的气垫船水下辐射噪声数值分析

气垫船水下声辐射是复杂的船体结构-气垫-周围水体三类介质声振耦合过程,其声传递特性是气垫船声学分析中的难点。本文以某全垫升气垫船为研究对象,结合声固耦合有限元法与解析法,探究气垫船水下辐射噪声传递特性。通过建立固-气-液声固耦合有限元模型,计算机械激励与垫升风机声激励,并以试验固有频率修正数值模型;通过声透射解析公式计算空气螺旋桨、燃气轮机等设备声激励辐射的水下噪声。采用距离左、右舷1 m处线上各点的总声压级作为评价指标。结果表明:气垫船水下辐射噪声为宽带噪声;有限元法计算的水下辐射噪声在低频时集中分布于气垫-周围水体耦合面附近,随着频率的升高,水下噪声增大并逐渐呈不规则干涉状分布;空气螺旋桨等声激励直接辐射水下噪声主要为近场低频噪声,在设备声激励辐射范围内声压平均占比约为40%。本文揭示的水下辐射噪声传递特性对气垫船减振降噪具有重要指导意义。

恒压供水在井群长距离输水工程中应用与研究

北京市未来科技城供水工程是保证供水安全,支撑未来科技城发展的需要。本文结合未来科技城供水工程设计实例,就恒压供水方式对整个供水系统的影响等关键问题进行了系统研究,分析供水系统中各个参数对系统的影响,研究类似工程中的水泵、变频与调流阀的联合控制等问题。对水泵进行调速性能曲线拟定,通过对各水泵并联曲线拟合,通过作图法求出调速比,对整个输水系统建立模型,进行输水系统过度过程计算及分析;对低流量工况下,工频与变频对系统的影响进行了对比。简要阐述了输水系统中封闭管道流体数学模型的原理及分析过程。通过理论分析、数值计算等,提出了未来科技城供水工程过渡过程计算的分析结果,为井群离输水工程设计及运行管理提供了科学依据及技术支撑。

基于QC方法减少长距离高起伏输水管线设计工日

针对近年来长距离、高起伏复杂输水管线出现频率日益增多的情况,为有效减少设计工日,QC小组通过现状调查分析确定了“输水管道布置设计耗时多”为主要症结。根据主要症结并兼顾其他因素,设定了活动目标,通过因果分析找出了6项末端因素。运用调查分析法确认了“水锤模拟分析过程复杂”和“管线路径决策流程不完善”2项要因。针对这2项要因,小组成员按照“5W1H”的方法进行了分析讨论,并制定了相应的对策。这些对策得到了有效落实,实现并超越了目标值,设计工日稳中有降,经济效益显著,具有一定的推广应用价值。

承压含水层水压传递速率变化规律

含水层内水压以能量的形式传递,其传递速率远大于水质点的迁移速率,水压传递速率对高压水体下工程安全施工及灾害预测预报具有重要意义。以无黏性土承压含水层为研究对象,通过理论分析、数值模拟、现场试验及室内物理模型试验等方法对水压传递速率变化规律进行探讨。结果表明:含水层中水压变化传递具有明显的滞后性,传递速率并不是无限大或接近声速,且存在随传递距离增加逐渐衰减的现象,水压径向传递的滞后时间t与水压传递距离r呈二次幂函数关系;稳定边界压力水头越大,在承压含水层中同等水压变量的传递速率越快,渗透系数越大水压传递速率越快;当渗透系数一定时,水压传递滞后时间与传播距离的拟合系数C随边界稳定压力水头的增加呈一阶指数函数减小;现场试验表明,边界稳定压力水头差异性不大时,在传输距离较远的条件下,其水压传递平均速率基本相当;室内试验表明,瞬态脉冲水压力随传递距离增加,波形发生明显变异,峰值压力逐渐减小、脉冲压力波波长变大、峰值压力传递速率减小,随传输距离的增加其传递速率呈指数函数衰减,说明瞬态脉冲水压力能量随传输距离增加快速衰减;瞬态脉冲压力值越大其初始阶段的传递速率越快,但随传输距离的增加其传递速率衰减幅度更大。研究成果对水压传递速率变化规律的影响机制及其应用于地下工程突水灾害预测及防治具有重要的理论及实践指导意义。

长距离输调水工程大口径FRPM管道研发与工程安全保障技术

长距离输调水工程是中国新疆地区重要的基础生命线,其长久稳定运行对于促进经济平稳增长和保障居民供水安全至关重要。新疆位居大陆中心,属温带极端大陆性气候,其长距离输调水工程面临严峻的环境挑战。玻璃纤维增强塑料夹砂管(glass fiber reinforced plastic mortar pipes,FRPM)作为长距离输调水工程中重要的水工地下结构用材,凭借其优异的耐化学腐蚀、轻质高强、无二次污染、安装方便、综合造价低等诸多优良特性而被广泛应用于新疆地区。然而,传统FRPM管生成工艺在铺层设计与生产自动化程度方面存在一定局限,导致工程施工过程效率低下;同时,缺少统一的技术标准和设计规范也间接制约了其应用范围。此外,管道工程自动巡检技术与缺陷定量评价标准尚未统一,无法合理量化和准确评价整体工程质量。为此,依托北疆小洼槽供水工程,围绕长距离大口径FRPM管的管材铺层设计与制造工艺、工程设计、质量评定、自动巡检、运行监测与安全保障等关键技术,通过产学研用相结合,持续15年攻关,取得突破性创新成果:①引进吸收并创新了适合于长距离、高工作压力、以连续缠绕工艺为首选的FRPM管生产工艺,优化了大口径FRPM管材铺层设计方法,实现了供料—缠绕—固化—切割—检测全自动化控制,与国外同类产品标准相比,管道挠曲性能和轴向拉伸强度等提高了20%~50%;②提出了安全防护的工程和非工程措施,建立了长距离FRPM管不同缺陷类型危害性等级划分原则,创建了复杂地质条件下长距离FRPM管道工程安全评价理论与方法;③系统揭示了FRPM管质量缺陷产生机理,开发了FRPM管光固化片材局部修复工艺以及内衬聚乙烯(PE)的整体非开挖修复技术,提出了修复效果后评价方法,实现了对长距离FRPM管道工程运行安全的有效掌控。

纤维复合材料在调水工程长输管道中的应用

调水工程长距离输水管道的材料选择,对工程成本和输水线路的安全有着重要影响。纤维复合材料具有轻质高强、内壁光滑、耐腐蚀性好等特点,正逐步应用在输水管道中。文章分析了影响长距离输水管道材料选择的主要因素,介绍了钢管、球墨铸铁管、混凝土管等传统输水管道的材料特性,阐述了纤维复合材料在输水管道中的应用,重点分析了玻璃钢夹砂管的发展和特点,最后对纤维复合材料输水管道在产品升级、施工技术、安全防护和质量管理四个方面的发展进行了展望。

花生油基烯效唑乳液的制备及在土壤中横向传输研究

烯效唑是一种广谱、高效的植物生长调节剂,受现有剂型影响,在土壤中的运移易受阻,导致大部分药物不能扩散到植物根系,从而降低其利用率。基于以上问题,本文利用花生油作为油相制备了烯效唑水包油型乳剂,通过构建横向传输模型土柱,在乳液分散方式、乳化剂类型、乳液浓度、乳液流速以及横向传输距离等方面考察了花生油基烯效唑乳液在土柱中的横向传输能力,并与烯效唑的水分散剂比较,表明烯效唑乳剂较水分散剂具有更强的横向传输能力。当烯效唑乳液浓度为500 mg·L^(-1),进样流速为1.23 mL·min^(-1),横向传输距离为40 cm时具有较好的横向传输能力。本文的研究结果将为烯效唑的绿色高效使用提供参考。

环状气囊水消声器声学性能的预测与分析

水消声器作为一种有效的噪声控制装置被广泛应用于水管路系统。分别使用模态匹配法和有限元法对环状气囊水消声器的声学性能进行仿真计算,分析气囊水消声器声学特性的原理,并研究气囊水消声器不同媒介间的特性声阻抗大小关系对消声性能的影响规律。计算结果表明:由于阻抗失配关系,在气囊水消声器中气体对声波的传递起主要反射作用。随着橡胶的特性阻抗增大,橡胶会对从水中传递过来的声波起到一定的阻碍作用。当气体体积被压缩时,气体对声波的反射衰减效果会逐渐减弱,从而使得气囊水消声器的传递损失曲线整体幅值下降,消声性能减弱。

装配式柔性墙体日光温室联合储热系统蓄放热特性

增设多蓄热介质联合主动蓄放热系统是解决装配式柔性墙体日光温室“重保温、轻蓄热”问题的有效方法,但当前对于“土壤-空气-水”多介质联合储热系统蓄放热特性和加温效果尚不明确,针对此问题,该研究以配备“空气源地中热交换-水源后墙循环换热”联合储热系统的装配式柔性墙体日光温室为研究对象,采用现场跟踪测试和能量转移测算,对联合储热系统各自和组合的蓄放热特性进行研究。结果表明,配有联合储热系统的装配式柔性墙体日光温室室内夜间最低空气温度维持在10℃以上,室内外最大温差达26.5℃。0~50 cm的土壤层是该温室主要蓄热介质,晴天土壤层蓄热量最高占总蓄热量的63.5%。地中热交换系统最高占土壤蓄热量的54.4%。水循环系统蓄热量可达424.04 MJ,最高占总蓄热量的45.1%,通过循环蓄热可将储水池内8 m3水的温度提高到35℃。连阴天时,通过引入蓄放热比指标,对联合储热系统的运行效果进行定量评价,发现水循环系统具有蓄放热速度快的特点,蓄放热比绝对值最高可达1.62,是当天土壤蓄放热的1.8倍。但从总量上看,土壤仍是连阴天主要放热来源,在北京地区联合蓄放热系统能够维持3个连阴天的热量需求。水循环系统平均性能系数(coefficient of performance,COP)为9.16,地中热交换系统平均COP为6.82,联合蓄放热系统综合COP为8.85,对比热泵,其节能率达60.26%。研究结果为联合储热系统蓄放热机理研究提供了理论依据。

有压输水管道内泥沙淤积形态及水力特性研究

为探究有压管道中泥沙淤积特性和泥沙的引入对管道水力参数的影响,以盐环定扬黄输水工程管道为例,采用物理模型观测与数值模拟相结合的方法开展研究。结果表明:模拟所用数学模型在计算结果上与物理模型试验观测数据及理论计算值基本一致,具有良好的适宜性;管道上升段底部泥沙在大流量下呈集中堆积分布,小流量下呈间断式分布,管道下降段底部泥沙在小流量、小坡度时出现间断分布特征,流量和坡度增大后呈带状分布;泥沙通过上升段之前,下降段小坡度泥沙淤积量与流量成反比,下降段大坡度和水平段泥沙淤积量与流量成正比;管道中泥沙的临界不淤流速与泥沙粒径成正比;管道上下游水位差在引入泥沙后增大,幅度在0.43~2.27 cm之间;管道断面流速在引入泥沙后略微减小,最大减小0.045 m/s,且泥沙进入管道会使断面峰值流速上移;各断面压强在清水和水沙条件下基本不变,最大仅相差0.46%。