EFFECT OF ORIFICE HYDRAULIC AND GEOMETRIC CHARACTERISTICS ON LEAKAGE IN WATER DISTRIBUTION SYSTEMS

Leakage from water distribution systems have significant economic and environmental impacts. Reducing leakage from distribution systems has favorable effects on the environment and energy consumption. This paper aims to understand the implications of orifice hydraulic and geometric characteristics on leakage flow. An experimental model was thus designed and built to simulate leaking water pipes with different defects. Various parameters were considered, including the size and shape of the orifice, Reynolds number (Re), and cavitation development in the orifice. During the tests, water was allowed to flow through the defects at controlled pressures while observing leak behavior. The results showed that the discharge coefficient (Cd) exhibited an extensive range (0.35-0.88) depending on the size and shape of the orifice and the flow conditions. The impact of cavitation can be so significant that it leads to variations in the discharge coefficient that are larger than those occurring with Re. A model is then presented to predict leakage rates at different flow conditions (i.e., cavitating and non-cavitating flow). Comparing the results shows a good fit between projected and measured flow values.