Effect of variation of empirical exponent coefficient values in water distribution network analysis

Abstract

The water distribution network supplies water to consumer to fulfill demands at desired pressure. Due to pressure deficient conditions pressure fall below minimum required which ultimately lead to reduction in flow supplied to consumer. The water distribution network is said to be pressure deficient, if the pressure head in each node is less than the required head. Adding artificial element approach for predicting partial flow at demand node in pressure deficient condition is used by many researchers. The objective of study is to investigate effect of variation in empirical exponent coefficient on emitter exponent, pressure and actual demand at demand node. The steady state simulation is carried out for case study network with pressure deficient node as emitter node using Fictitious component free – Pressure Deficient Network Algorithm. The emitter coefficient formula, derived from Wagner’s equation is used for predicting actual demand under pressure deficient condition. The value of emitter coefficient depends on emitter exponent coefficient value, which is calculated using empirical exponent coefficient. The study is carried out for three different values of empirical exponent coefficient 0.5, 1, 1.5, 1.852, 2 and 2.5 respectively. The simulation analysis shows that as empirical exponent increases emitter exponent decreases, pressure decreases and actual demand at nodes increases. This study can be useful in calculating resilience index, which is measure of average efficiency of water distribution network under pressure deficient condition.