供水管网是城市基础设施的重要组成部分。由于地理环境以及人为破坏引起的供水管网漏失问题，直接影响供水管网的健康状态，同时微小漏失长时间冲刷形成地下空洞等隐蔽风险，及其诱发的路面塌陷等次生衍生事故，严重威胁城市安全运行。目前国内外成熟的供水管道漏失检测与定位技术主要以大漏失量为主，难以实现城市供水管网的微小漏失检测与精准定位。如何应用流体力学、声学等基础理论和声波检测分析、多数据融合定位技术，研究管网内精准检测与定位技术，是城市供水管网安全防控的重要科学和技术问题。本文以城市供水管网微小漏失精准检测与定位为研究目标，研制了供水管网漏失检测系统，并实现了工程化应用。主要研究内容与成果如下：研究了城市地下供水管道漏失声波管内传播规律和微小漏失识别方法。建立了三维非稳态漏失声学模型，分析了管内漏失声波在不同管道环境传播过程中各参量的衰减特性与变化规律，揭示了地下供水管网漏失声波管内传播机理与衰减特性。在此基础上创新引入听觉显著图作为供水管网漏失识别检测的技术方法，构建了一种基于声波信号时频特性的微小漏失检测识别算法。研究了刚性球体管内运动场变化规律。研究了刚性球体管内运动受力特性，分析了刚性球体管内运动受力特性与流场各状态参数之间的关系，建立了球体管内运动受力模型，揭示了刚性球体管内稳定运动状态下速度场各参数之间的变化规律，为漏失检测仪管内运动跟踪以及漏失点定位技术研究提供理论依据。研究了复合超声波振子耦合振动规律与管内漏失联合定位方法。分析了复合振子的机电耦合特性、响应特性与能量转化效率，设计了复合超声波振子结构，解决了超声波远距离传播问题；研究了基于超声波及MEMS数据融合的管内漏失联合定位方法，构建了一种基于扩展卡尔曼滤波（EKF）的综合滑动速度与位置在线分析算法，实现了漏失检测仪管内远距离跟踪与漏失点精准定位。研建了满足不同工况条件的漏失检测模拟实验平台，完成了漏失检测装置的系统设计，并实现了现场工程应用，整体效果良好，工程应用结果表明：城市供水管网漏失检测与定位技术能够实现漏失定位精度不大于±2.5m/km，漏失精度不大于0.3L/min。
Water supply pipeline network plays a critical role in urban infrastructure. Linkage of water supply pipeline caused by geographical environment and artificial damage would have direct impacts on its safe operation. At the same time, the long-term small leakage would seriously threaten the urban safety due to the hidden risks like underground cavity and the secondary derivative accidents like road collapse. Currently, water supply pipeline leakage detection and positioning technologies at home and abroad have primarily concerned on large leakage, unable to detect and locate small leakage accurately. It is an important scientific issue for the safety prevention and control of water supply pipeline to study the precise detection and positioning technology with fluid mechanics, acoustics, sound wave detection and analysis, and multi-data fusion positioning. Therefore, this paper develops leakage detection system for water supply pipeline network and applies this detection technology into practice by targeting the precise detection and position of small leakage. The main contents of this paper are as follows:The leakage acoustic propagation of urban underground water supply pipeline and small leakage identification were studied. A three-dimensional unsteady state leakage acoustic model was established, and the attenuation characteristics and changes of various parameters of leakage acoustic waves transmitted in different pipelines were analyzed, and then the leakage acoustic propagation of underground water supply pipeline and small leakage recognition were revealed. Based on previous efforts, saliency map was firstly introduced as a technical method to detect the water supply network leakage. Small leakage detection and recognition algorithm of acoustic signal based on time-frequency characteristics was constructed.The change law of rigid sphere’s motion field inside pipeline was studied. Based on the movement force characteristics of rigid sphere inside pipeline, relationship between the sphere's motion inside pipeline and the fluid field parameters was analyzed. The movement force model of sphere inside pipeline was established. The change law of stable motion parameters of velocity field was summarized. It provided a theoretical basis for the motion tracking of leakage detector and leakage positioning.The coupling vibration law of composite ultrasonic oscillator and the leakage joint positioning were studied. The electromechanical coupling characteristics, response characteristics and energy conversion efficiency of composite oscillator were analyzed. Structure of composite ultrasonic oscillator was designed, solving the problem of long-distance ultrasonic propagation. Joint pipeline leakage positioning based on ultrasonic and MEMS data fusion was studied. Online analysis algorithm between general sliding speed and location based on Extended Kalman Filter (EKF) was established. The long-distance tracking of leakage detector inside pipeline and the leakage precise positioning were implemented.Simulation test platform for the leakage detector under different working conditions was established. The leakage detector system was designed, achieving the practical application. The overall effect was good. The practical application results suggest that leakage detection and positioning technology for urban water supply pipeline network can achieve the positioning accuracy of no more than ±2.5m/km and the leakage accuracy of no more than 0.3L/min.
