IMPACT OF TRANSITIONFLOW REGIME ON CONTAMINANTS PROPAGATIONIN PRESSURISED PIPES

In recent years, the scientific community has focused a lot of attention on the problem of water quality within the distribution networks in order to prevent and identify any presence of contaminants that might insist within it. In literature, several numerical models are available able to identify, position, represent and simulate the propagation of contamination in pressurized pipe networks. Unfortunately, these models adopt simplified approaches that do not lead to significant errors when dealing with fully developed turbulent flow regimes, but which could lead to relevant overestimation of contaminant concentrations in transition flow regime with low velocity. For this reason, the diffusive - dispersive processes have to be investigated in order to make the models more realistic. With this aim in mind, the present paper aims to investigate the effect that the different flow regimes impose on a conservative contaminant (NaCl) in order to better understand the diffusive - dispersive phenomenon within the water networks. To do this, experimental contamination tests were performed on a laboratory network, in a controlled environment (Enna, Italy). The monitoring campaign was performed through conductivity sensors positioned in specific nodes of the network functioning in real - time. Several tests have been carried out for different values of the Reynolds number, both through laboratory experiments and through the use of the EPANET hydraulic simulator. The model was modified in order to take into the diffusion - dispersion processes that are relevant for the low Reynolds numerical values.