scholarly journals Formula for determining the size of the air tank in the long-distance water supply system

2020 ◽  
Author(s):  
Xuyun Chen ◽  
Jian Zhang ◽  
Nan Li ◽  
Xiaodong Yu ◽  
Sheng Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Water Supply ◽  
Theoretical Calculation ◽  
Selection Process ◽  
Supply System ◽  
Water Supply System ◽  
Operating Parameters ◽  
Long Distance ◽  
Calculation Results ◽  
Simulation Results

Abstract In the long-distance water supply system, the air tank can effectively protect the water hammer when the pump stops, and the shape parameters of the air tank determine the protective effect. Based on the theory of rigid water body and harmonic vibration, this paper derived the calculation formulas for the surge and bottom pressure changing process of the air tank in the system with and without friction and impedance and put forward the theoretical method to estimate the air tank volume and established the relationship between the operating parameters and the volume. Combined with the actual water supply project, under different working conditions, the theoretical calculation results and numerical simulation results were compared and analyzed. The results showed that the theoretical calculation results of the system with friction and impedance had a better fitting performance than the numerical simulation results, and the operating parameters of the air tank derived after considering the influence of friction and impedance were accurate. This method can simplify the selection process of air tank body parameters. At the same time, the shape optimization of the air tank considering friction and impedance can be improved by 40–50% compared with the results of ignoring friction and impedance.

scholarly journals A Case Study on Risk Assessment of Long Distance Water Supply System

2014 ◽  
Vol 70 ◽  
pp. 1762-1771 ◽  
Author(s):  
J. Zhang ◽  
J. Gao ◽  
M. Diao ◽  
W. Wu ◽  
T. Wang ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Water Supply ◽  
Supply System ◽  
Water Supply System ◽  
Long Distance

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.

Chlorine dioxide disinfection by-products in the Nová Bystrica-Čadca-Žilina long distance water supply system

2006 ◽  
Vol 6 (2) ◽  
pp. 209-214
Author(s):  
J. Kriš ◽  
K. Munka ◽  
E. Büchlerová ◽  
M. Karácsonyová ◽  
L. Gajdoš
Keyword(s):  
Water Supply ◽  
Chlorine Dioxide ◽  
Distribution System ◽  
Supply System ◽  
Water Supply System ◽  
Water Disinfection ◽  
Long Distance ◽  
Residual Concentration ◽  
Chlorine Dioxide Disinfection ◽  
By Products

In a process of water disinfection it is necessary to distinguish between primary disinfection focused on removal or inactivation of microbiological contaminants from raw water, and secondary disinfection focused on maintenance of residual concentration of the disinfector in distribution system. Current practice related to disinfection follows two approaches. The paper presents results from a stage task solution “Research of physical-chemical changes in water quality during its distribution” at the Nová Bystrica-Čadca-Žilina long distance water supply system (LDWSS) focused on the presence of disinfection by-products by using chlorine dioxide.

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.

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