Polyline Closure Law Design and Realization in Long-Distance Water-Supply Project

2010 ◽  
Author(s):  
Jian Zhang ◽  
Xiaodong Yu ◽  
Jianfeng An ◽  
Arash Hazrati
Keyword(s):  
Water Supply ◽  
Theoretical Basis ◽  
Temporal Distribution ◽  
Break Point ◽  
Water Hammer ◽  
Long Distance ◽  
Closure Time ◽  
Water Conveyance ◽  
Flow Inertia ◽  
Application Scope

Long-distance water-supply project is an effective way to solve the uneven spatial and temporal distribution of water resources, but the safety of water conveyance system is threatened seriously by water-hammer. Based on the research of the characteristic of water-hammer with pipe friction considered, the formula of indirect water-hammer is deduced and the application scope of the formula is also discussed, which is the theoretical basis for the design of polyline closure law. To the defects that valve closure time is long and response of accident is slow in the long-distance water-supply project, polyline closure law is designed with consideration of valve overflowing property, which greatly reduces the closure time and water-hammer. At the same time, the flow inertia is large in long-distance water-supply project and break point of polyline closure law is hard to fix. In order to improve the reliability of the mechanical operating system, locking device is installed, which make the polyline closure law carry out successfully and provide a new idea for water hammer protection in long-distance water-supply project.

scholarly journals Research on the water hammer protection of the air vessel caused by underground pipe burst in long distance water supply system

2018 ◽  
Vol 246 ◽  
pp. 01066 ◽  
Author(s):  
Xingtao Wang ◽  
Jian Zhang ◽  
Xiaodong Yu ◽  
Lin Shi
Keyword(s):  
Water Supply ◽  
Check Valve ◽  
Water Hammer ◽  
Supply System ◽  
Water Supply System ◽  
Safe Operation ◽  
Long Distance ◽  
Underground Pipe ◽  
Pipe Burst ◽  
The Mathematical Model

The conventional air vessel installation is usually installed behind the check valve at the upstream end of the pipeline to effectively control the water hammer pressure due to pump trip. However, the water hammer pressure caused by underground pipe burst has been neglected. The water hammer protection of air vessel due to pipe burst in long distance water supply system was discussed in this paper. According to analysis of the process of the pipe burst, the mathematical model of underground pipe burst and air vessel were established. A new air vessel installation that was installed in the middle of the pipeline was proposed. The new air vessel installation was simulated by method of characteristics. Then it was compared with the conventional air vessel when the pump trip and the pipe burst occur respectively. The results show that both the conventional air vessel and the new air vessel can effectively protect the water hammer duo to the pump trip. Moreover, when pipe burst occurs, the conventional air vessel cannot achieve the safe operation of the long distance water supply system. However, under the same air vessel type parameters, the new air vessel installation can effectively protect the water hammer pressure.

Analysis of Full-Featured Pump Curve to Study the Impact of Large Diameter, Long Distance and High-Lift Water Pipeline

2011 ◽  
Vol 90-93 ◽  
pp. 2954-2959
Author(s):  
Yu Si Yang ◽  
Li Liu ◽  
Kun Li
Keyword(s):  
Water Supply ◽  
Large Diameter ◽  
Water Hammer ◽  
Urban Water Supply ◽  
Long Distance ◽  
High Lift ◽  
Pumping Stations ◽  
Water Pipelines ◽  
Water Pipeline ◽  
The Impact

According to the situation of Chinese urban water supply, this article has analyszed the possibility and computing method for water hammer that caused by pump stop in large diameter and high-lift water pipelines. In addition the impact of Full-featured Pump Curve on the water hammer calculation are also discussed. Finally, using the water hammer calculation of the primary pumping stations within a water-supply project which located in northeast China as an example, we had made corresponding conclusion.

Effect of multi-valve closure on superposed pressure in a tree-type long distance gravitational water supply system

2019 ◽  
Vol 68 (6) ◽  
pp. 420-430
Author(s):  
Xingtao Wang ◽  
Jian Zhang ◽  
Xiaodong Yu ◽  
Sheng Chen ◽  
Wenlong Zhao ◽  
...  
Keyword(s):  
Water Supply ◽  
Pressure Rise ◽  
Water Hammer ◽  
Supply System ◽  
Water Supply System ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Long Distance ◽  
Maximum Water ◽  
Tree Type

Abstract Valves are installed at the end of each branch pipeline in a tree-type long distance gravitational water supply system to regulate flow. However, the sequential closing of all valves may cause a tremendous superposed pressure rise, even larger than the pressure rise under simultaneous valve closure. In this paper, the effects of sequential valve closure on the superposed maximum water hammer pressure rise in a pipeline were investigated. By using the wave superposition principle, a sequential valve closure formula leading to maximum water hammer was proposed and verified using numerical simulation based on a practical project. In addition, the superposed maximum pressure rises in the pipeline were compared under single, simultaneous and sequential valve closure, respectively. The results show that the sequential valve closure formula agrees well with the numerical results and the pressure rise in the pipeline under the sequential closing was the largest. Moreover, compared with the superposed maximum pressure rises at the main pipeline, the effect of sequential valve closure on superposed maximum pressure rise at the branch pipeline is more sensitive.

Analysis on Air Valve Placement in Long-Distance Water Conveyance Pipeline System

2012 ◽  
Vol 610-613 ◽  
pp. 2513-2518
Author(s):  
Shi Feng Huang ◽  
Feng Wang ◽  
Hui Xu ◽  
Xiao Xian Wei
Keyword(s):  
Water Hammer ◽  
Pipeline System ◽  
Key Factors ◽  
Long Distance ◽  
Protection Measures ◽  
Pressure Pipeline ◽  
Pipeline Project ◽  
Water Conveyance ◽  
Air Valve ◽  
Exhaust Valves

Water hammer is one of the key factors that can cause accidents by the burst of pressure pipeline. Important features and related reasons of accidents caused by water hammer in long-distance water conveyance pipeline system were introduced, and protection measures were presented. An long-distant raw water conveyance pipeline project was taken as an example to study on the influence of protective effect by different placement schemes of air valves based on hydraulic transient simulation and analysis. Results shows that largest number of air valves does not reach the best and unreasonable placement of air valves might be the cause of an accident. It is critical to select the proper location of air valves, it is necessary to pay more attention on local hump in the front of pipeline near the pump and put exhaust valves instead of inlet valves at the back of pipeline (except some higher hump location).

Analytical solutions for predicting the maximum pressure drop after pump failure in long-distance water supply project

2018 ◽  
Vol 18 (6) ◽  
pp. 1926-1936 ◽  
Author(s):  
Cheng-yu Fan ◽  
Jian Zhang ◽  
Xiao-dong Yu
Keyword(s):  
Pressure Drop ◽  
Water Supply ◽  
Safety Assessment ◽  
Water Hammer ◽  
Maximum Pressure ◽  
Long Distance ◽  
Pump Failure ◽  
Pipe System ◽  
Protection Scheme ◽  
Maximum Pressure Drop

Abstract The water hammer caused by pump failure in a long-distance pressurized pipe system generally poses a severe threat to the safety of the whole system. The maximum pressure drop at the pump end of the discharge line is significant for the safety assessment of the pipelines. In this study, the characteristics of the pump-stopping water hammer and its propagation in the pipelines are analyzed. The formula for predicting the maximum pressure drop is deduced based on the Method of Characteristics and the complete characteristics of the pumps. The application conditions of the formula and the solution procedures are presented as well. In addition, two engineering cases are introduced and the results calculated by the formula are compared with those resulting from the numerical simulation, and the agreement is satisfactory. The formula presented in this study is of simple form, practical and of high precision, and can provide a theoretical basis for the water hammer protection scheme of a long-distance water supply project.

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