On hydraulic calculations of a loop water distribution network
(to be discussed)

Summary

During the operation a loop water distribution network is subject to both disturbing impact and control activities. Disturbing impact aims at changing the state of the network. At that the operating personnel try to maintain the network in 100% working conditions at minimum costs by the control activities. Disturbing impact is caused by water consumption alterations and pipeline failures that arise stochastically. In the process of hydraulic designing water consumption variations are simulated with so called specific modes chosen at the most crucial moments of the water network operation. Hydraulic calculations of the specific modes are carried out provided the network is in complete function. The model of a loop water distribution network operation does not take into account the disturbing impact of failures. The construction rules and regulations determine only the level of the network operation in case of a single section cutoff. For simulating the process of failure occurrence and elimination the use of the mathematical tools of a queue system is suggested. The calculations show that at the existing water network failure rate and repair time the loop water distribution network is in non-operating condition at least for three and more weeks over a year. The procedure of hydraulic calculation of a loop water distribution network with account of occurring failures and repair time is suggested.

Key words

water consumption , hydraulic design , loop water distribution network , state of failure , repair time , regulating facilities

Ways to improve the municipal water supply and distribution system

Summary

Simulation of all possible switch-overs in the municipal water distribution network caused by fault section cutoffs is practically unfeasible because of the large number of simulation cases. For the implementation a method of the distribution network dividing into separate districts (zones) with water flow rate measured at the input and outlet is suggested in a similar way to the elimination of leaks. Within the limits of each district including up to 50 km pipelines the search of the isolated sections becomes feasible. At that determining the reliability of the water supply in each district as a part of the annual period when the customer receives water on a regular basis is possible. This is achieved with the use of Markov model for determining the period of the water distribution network being operational and in the state with simultaneously isolated sections. Then by hydraulic calculations the parameters of the network in non-operating conditions are determined; at that it is determined which parameters are related to the operation period with normal or lowered level of performance.

Key words

water supply network , hydraulic design , water supply reliability , state of failure , state of failure , Markov model