Haixing Liu

Battle of the Water Networks II

The Battle of the Water Networks II (BWN-II) is the latest of a series of competitions related to the design and operation of water distribution systems (WDSs) undertaken within the Water Distribution Systems Analysis (WDSA) Symposium series. The BWN-II problem specification involved a broadly defined design and operation problem for an existing network that has to be upgraded for increased future demands, and the addition of a new development area. The design decisions involved addition of new and parallel pipes, storage, operational controls for pumps and valves, and sizing of backup power supply. Design criteria involved hydraulic, water quality, reliability, and environmental performance measures. Fourteen teams participated in the Battle and presented their results at the 14th Water Distribution Systems Analysis conference in Adelaide, Australia, September 2012. This paper summarizes the approaches used by the participants and the results they obtained. Given the complexity of the BWN-II problem and the innovative methods required to deal with the multiobjective, high dimensional and computationally demanding nature of the problem, this paper represents a snap-shot of state of the art methods for the design and operation of water distribution systems. A general finding of this paper is that there is benefit in using a combination of heuristic engineering experience and sophisticated optimization algorithms when tackling complex real-world water distribution system design problems

A diameter‐sensitive flow entropy method for reliability consideration in water distribution system design

Flow entropy is a measure of uniformity of pipe flows in water distribution systems. By maximizing flow entropy one can identify reliable layouts or connectivity in networks. In order to overcome the disadvantage of the common definition of flow entropy that does not consider the impact of pipe diameter on reliability, an extended definition of flow entropy, termed as diameter-sensitive flow entropy, is proposed. This new methodology is then assessed by using other reliability methods, including Monte Carlo Simulation, a pipe failure probability model, and a surrogate measure (resilience index) integrated with water demand and pipe failure uncertainty. The reliability assessment is based on a sample of WDS designs derived from an optimization process for each of the two benchmark networks. Correlation analysis is used to evaluate quantitatively the relationship between entropy and reliability. To ensure reliability, a comparative analysis between the flow entropy and the new method is conducted. The results demonstrate that the diameter-sensitive flow entropy shows consistently much stronger correlation with the three reliability measures than simple flow entropy. Therefore, the new flow entropy method can be taken as a better surrogate measure for reliability and could be potentially integrated into the optimal design problem of WDSs. Sensitivity analysis results show that the velocity parameters used in the new flow entropy has no significant impact on the relationship between diameter-sensitive flow entropy and reliability.

Failure Impact Analysis of Isolation Valves in a Water Distribution Network

Bentley Systems provided the software to conduct the hydraulic simulation and valve segmentation. This study is financially supported by the National Natural Science Foundation of China (51320105010, 51579027), the National Science and Technology Major Project (2014ZX03005001), and Ministry of Water Resource of China (Grant No.201401014-2), which are greatly acknowledged.

Optimization of Monitoring Point Placement of Water Quality in the Water Distribution System Based on TEVA-SPOT

With the global escalation of terrorist attacks, water supply network has become the weak links exposed to terrorists. Many countries have already raised infrastructure security as homeland security strategies, developing a corresponding tool to simulation and analysis vulnerability for the water distribution system (WDS). This paper is aiming at the non-source pollution in the WDS, and the water quality monitoring points are established. According to the theory of tracing exogenous pollutants in water distribution network, the model is developed by TEVA-SPOT optimizing monitoring point placement of water quality. This study is working to reduce system vulnerabilities, prevent and prepare for terrorist attacks, minimize public health impacts and infrastructure damage, and enhance recovery.

Study of Mixing at Cross Junction in Water Distribution Systems Based on Computational Fluid Dynamics

Solute mixing at the cross junction was assumed to be instantaneous and completely mixed in initial water quality models of water distribution system. With recent developments, some computational simulations and experiments verified an incomplete mixing state at cross junctions, which affected the accuracy of water quality model in water distribution networks. This paper, by the theory of computational fluid dynamics, confirms incomplete mixing at the pipe intersections. At the cross of pipe network, the forward direction of the fluid particle is directly related to water momentum. A mixing model at the cross in water supply networks is established to improve the water quality model and the simulation accuracy. For the potential of accidental or intentional contamination events, it makes a powerful prediction. This study is working to prevent and prepare for terrorist attacks, minimize public health impacts and infrastructure damage, and enhance recovery.

Correction to: Assessing real options in urban surface water flood risk management under climate change

The article “Assessing real options in urban surface water flood risk management under climate change”, written by Haixing Liu, Yuntao Wang, Chi Zhang, Albert S. Chen and Guangtao Fu, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 21 May 2018 without open access.

EXPERIMENTAL STUDY OF GAS-WATER PULSE PIPE CLEANING

Growth-rings form in water supply pipelines during annual operation, reducing flow rate and runoff and increasing resistance coefficient, affecting the turbidity, taste, odor and color of water supply, which result in secondary pollution of water in pipelines, and thereby endanger people’s health. Pipe Cleaning is the most effective and simplest method for removing growth-rings and reducing secondary pollution. Of all pipe cleaning techniques, gas-water pulse pipe cleaning is a highly efficient, water-saving and low-cost one. This study investigated the cleaning law of gas-water pulse pipe cleaning through self-established experimental platform. The results showed that different inflation/non-inflation intervals greatly affected the pressure change in pipelines when gas supply pressure and water supply flow were determined.