High speed photographic analysis of effect of aeration bubbles on cavitation bubbles

In order to solve the problem of cavitation damage due to high velocity flow,an aerator is usually used to aerate air into low-pressure region or upper region that cavitation damage occurs.And the mechanism of cavitation control by aeration in high-velocity flow involves in bubble dynamics.Cavitation characteristics of semi-cylindrical irregularity were observed by high speed photography in a noncirculating water tunnel.Variations of pressure and cavitation number within cavitation zone behind semi-cylindrical irregularities with both diameters of aeration hole and gas concentrations were measured.Regimes of cavitation clouds,evolutions and effects of different aeration bubble sizes on interaction between cavitation and aeration bubbles were photographically observed.Under the conditions of v=11.67 m/s,Qa=0.6 m3/h,0.8 m3/h,1.0 m3/h,and 10 mm high semi-cylindrical irregularity with 6mm in diameter of bottom,the experimental results showed that cavitation number of 2 mm aeration hole could reach the maximum.And the optimal diameter of aeration hole decreased with increase in gas concentration.