Experimental Test of Dynamic Moving Characteristics for Leak Detecting-Ball in Water Mains

The leak detecting-ball moving in pipes combined the sensors of the acoustic leak detection achieves the high responsiveness to small leaks of the water distribution system (WDS). The dynamic characteristics of the single sphere moving inside pressure pipes are studied for optimal design of the leak detecting-ball. The experimental balls having different densities are made of three types of material by using 3D printing, including tetrafluoroethylene (ETFE), photosensitive resin (PR) and wax. The balls have densities from 1.06 to 1.35 and different diameters, ball-to-pipe diameter ratios from 0.32 to 0.5. The Reynolds numbers of the pipe flows are from 1400 to 50000. The moving velocity of the balls with different pipe flow velocities, ball densities, and ball-to-pipe diameter ratios are investigated through the laboratory experiments. The velocities of balls in some of the experimental tests are greater than the average flow velocity. These larger balls rolled faster than the average flow velocity because of the maximum thrust by the pressure flow in the center of the circular tube section.