AWWA ACE61707

This paper studies the phenomenon of gaseous cavitation from a theoretical and practical perspective. A simulated distribution system was constructed to track gaseous cavitation using four independent measurements including visual observation of bubbles, an inline turbidimeter, an ultrasonic flow meter, and an inline total dissolved gas probe. All four measurements confirmed that gaseous cavitation was occurring within the experimental distribution system, even at relatively high system pressures. Gaseous cavitation increased at higher initial dissolved gas contents and was affected by temperature. Certain changes in pH, conductivity, and surfactant addition also tended to increase the likelihood of cavitation. For example, compared to the control at 30 psig system pressure, the turbidity increased 295% at pH 9.9. These bubbles in turn reduced the pump's operating efficiency causing the system velocity to be 17% lower. Cavitation clearly occurred in these experiments even though calculations suggested that it was unlikely. Includes 12 references, table, figures.