The Calculation Of Pipe Sections Including Valve In Water Supply Network

Adjusting the valve opening degree is an important method of schedulingand optimizing the pipe network. This article focuses on the derivation andapplication of head loss calculation formula in which valve is taken intoaccount, and we use the equivalent length of the valve in place of the valve andhydraulic perturbations length that is in different flow patterns before or afterthe valve. In the scheduling of the pipe network, the pressure changes of pipesegments are usually can be achieved by adjusting the flow rate, when we adjustthe valve opening degree, pipe flow pattern will be affected by thosechanges.Therefore, in order to study the pipe network optimization scheduling,the research about the flow characteristics when regulating valve is essential,which is also its theoretical basis.Valve settings and select has a great infuluence on the network reliability,simulating the pipe network which contains regulating valve in order to ensure that the pipe network’s reliability and find the best solution to adjust the valve.Valve is optimized in the pipe network in order to improve the reliability ofwater supply pipe network. In the basis of the hydraulic model, and combinedwith the hydraulic conditions and pipe network architecture, this paperanalysises network reliability.The main results of this paper made are the following points:1、In the water supply network, adjusting the valve opening degree canchange the flow pipe section and then control the pressure of pipe network’snodes in the water supply network, in the scheduling of this adjustment,which iscrucial.2、On the basis of classical mechanics, the perturbations length of theformula is derived. Valve makes the flow pattern which is near it is different,and different valve opening degree also makes corresponding hydraulicperturbations length different.3、 Compared with the previous pipe network hydraulic calculation,excluding the local head loss of the valve. In this paper, referencingpredecessors’ experiments, we get the flexibility length before and after thevalve, and the local loss of the valve is replaced by the loss of equivalentlength,which provides a simple way to calculate the head loss of the pipe withvalve. Tt provides network optimization scheduling with theoretical guidance.4、By application instance,it is concluded that if valve opening degree is lessthan0.4, valves have a great influence on the head loss, and the difference between the head loss which considers valve and flexible dynamic length andwhich dosen’t is obvious; if valve opening degree is greater than0.4thesechanges are small. Their relationship is when0.3，h总（3.0~3.3）h0；when0.30.4，h总（1.8~2.0）h0；when0.40.6，h总（1.2~1.5）h0；when0.61，h总1.1h0。This provides theoretical basis to optimize the schedulingaccurately.