Evaluation of Orifice Formulation for Leak Detection in Water Supply Systems Considering Unsteady Friction Term

Nowadays, water supply utilities in many parts of the world are concerned about water supply. Climate change, drought and population growth as well as immigration, are the most important factors for this situation. Because of limitation for availability of treated water, supplying healthy water even in areas with wet climate is difficult. In encounter with this challenge, reducing water losses in both trunk mains and distribution systems can be a temporary solution. In this research, a novel leak detection technique based on Frequency Response Method using transient flow analysis is presented in order to leak detection in water supply systems. In this method, in order to leak detection and location, steady-oscillatory flow in a pipe system, is generated by the sinusoidal maneuver of a valve in downstream of pipe and is analyzed in frequency domain with matrix transform. It is shown that leak presence in pipe, changes the shape of pressure frequency response. Pressure oscillation amplitude in even harmonies increases and in odd harmonies decreases. By this property, location of leak can be determined. Reliability of other methods depends on large amount of measured data in different parts of the system. The presented method, need to measure pressure and discharge data just in the location of valve. As an advantage of this method, leak discharge can be determined. By an example, the proposed methodology is evaluated and its advantages and disadvantages are distinguished.