Accuracy of single-jet water meters during filling of the pipe network in intermittent water supply

Abstract

Due to the alternate filling and emptying of pipe networks in intermittently operated water distribution systems, present air must exit the pipe network. A part of this air is discharged through house connections and, thus, leads to a use of water meters contrary to their initial conception. In this article, a study is presented in which the measurement error of horizontally mounted single-jet water meters in intermittent supply is investigated experimentally. It has been discovered that the measurement error is mainly caused by the air flow ahead of the arrival of the water front. The study shows an approximately linear correlation of the measurement error and the volume of air in front of the water meter. The impact of the water front itself, the presence of water-air mixtures or unsteady flow processes have only small influences on the measurement result.