본 연구는 실제 복합 상수도 관망 시스템에서 서지탱크의 직경 및 설치 위치에 따른 수두 감쇠 효과를 수치해석적으로 평가하고, 천이류 분석을 통해 상수도 관망 시스템에서 수격 방지 장치로서 활용되는 서지탱크의 최적 설계 및 배치 조건을 선정하고자 하였다. 천이류 기반 수치해석은 서지탱크 해석 이론이 결합된 특성선 방법 기반 모델을 통해 실제 상수도 관망을 단순화⋅골격화한 관망 시스템을 대상으로 수행했으며, 관망 시스템에서 천이류의 영향을 크게 받는 특정 절점을 선정하여 각 절점에서 밸브 조작 조건에 따른 천이류 발생 시나리오를 설정하였다. 먼저 밸브 급폐(1.337 s) 조건의 단일 시나리오에서 서지탱크의 직경별 성능을 비교한 결과, 수두 감쇠율이 0.61%∼13.31%로 나타난 직경 0.2 m 조건이 최적 직경으로 선정되었다. 다음으로 밸브 완폐(12.033 s) 조건의 시나리오에서 선정된 직경 0.2 m 서지탱크의 설치 위치를 평가한 결과, 46개 지점 중 37번 절점에 서지탱크를 설치하는 것이 수두를 25.44%∼32.22% 감쇠시켜 본 연구 조건에서 최대 감쇠 효과를 나타냈다.

배수 관망에서 가지관은 주 송수관에서 물을 주민에게 공급하는 핵심 요소이나, 일부는 불법적으로 사용되거나 정보가 불확실하여 관망 운영 효율을 저하시킨다. 본 연구는 단순 관망을 대상으로 천이류 해석과 실험을 통해 다중 가지관 탐지 기법을 검증하였다. 연구목적은 천이류 기반 가지관 탐색법의 적용 가능성을 평가하고, 관로 매개변수의 민감성을 분석하는 것이다. 개발된 방법은 단순 관로에서 전통적인 특성선 방법에 볼밸브의 비선형 거동 분석을 연계해 해석했다. 해석과 실험은 동일한 관망에서 두 개의 가지관을 대상으로 수행되었으며, 실험 내재 불확실성을 고려하였다. 두 분석 모두에서 구별 가능한 압력 신호가 확인되어 제안된 방법의 가지관 탐지 가능성을 입증하였다. 또한 결과는 불균일한 파속도와 일관되지 않은 천이류 유입 조건이 탐지 성능에 큰 영향을 미치는 것으로 나타났다.

The pressure sensor had been widely used to effectively monitor the flow status of the water distribution system for ensuring the reliable water supply to urban residents for providing the prompt response to potential issues such as burst and leakage. This study aims to present a method for evaluating the performance of pressure sensors in an existing water distribution system using transient data from a field pipeline system. The water distribution system in Y District, D Metropolitan City, was selected for this research. The pressure data was collected using low-accuracy pressure sensors, capturing two types of data: daily data with 1Hz and high-frequency recording data (200 Hz) according to specific transient events. The analysis of these data was grounded in the information theory, introducing entropy as a measure of the information content within the signal. This method makes it possible to evaluate the performance of pressure sensors, including identifying the most sensitive point from daily data and determining the possible errors in data collected from designated pressure sensors.

We propose a transient evaluation scheme using a pressure measurement in a complicate pipeline systems. Conservation of mass and momentum equations in time domain can be transformed into a pressure head and flowrate relationship between upstream and downstream point in frequency domain. The impedance formulations were derived to address measured pressure at downstream to evaluate of flowrate or pressure head at any point of system. Both branched pipeline element and looped pipeline element can be generally addressed in the platform of the basic reservoir pipeline valve system. The convolution of time domain response function with measured pressure head from a downstream point provides flowrate or pressure head response in any point of the designated pipeline system. The proposed method was validated through comparison between traditional method of characteristics and the proposed method in several hypothetical systems.

In this study, we propose a flow velocity evaluation scheme based on pressure measurement in pressurized pipeline systems. Conservation of mass and momentum equations can be decomposed into mean and perturbation of pressure head and flowrate, which provide the pressure head and flowrate relationship between upstream and donwstream point in pressurized pipeline system. The inverse impedance formulations were derived to address measured pressure at downstream to evaluation of flow velocity or pressure at any point of system. The convolution of response function to pressure head in downstream valve provides the flow velocity response in any point of the simple pipeline system. Simulation comparison between traditional method of characteristics and the proposed method provide good agreements between two distinct approaches.

In this study, a method of leakage detection was proposed to locate leak position for a reservoir pipeline valve system using wavelet coherence analysis for an injected pressure wave. An unsteady flow analyzer handled nonlinear valve maneuver and corresponding experimental result were compared. Time series of pressure head were analyzed through wavelet coherence analysis both for no leak and leak conditions. The leak information can be obtained through either time domain reflectometry or the difference in wavelet coherence level, which provide predictions in terms of leak location. The reconstructed pressure signal facilitates the identification of leak presence comparing with existing wavelet coherence analysis.

This paper suggests a nonlinear pressure consideration scheme through an unsteady pipe network analyzer for leakage detection with a portable pressure wave generator. In order to evaluate the performance of a proposal scheme, linear input pattern has been simulated and experiments had been carried out under both no leakage and one leakage conditions in a reservoir-pipeline-valve system. This method using portable pressure wave generator showed that a leakage can be detected from a reflection where a leakage is originated through time domain analysis. Meaningful similarity in pressure response between nonlinear input pattern and experimental results were found both no leakage and a leakage conditions.