Aeration efficiency of bottom-inlet aerators for spillways

The bottom-inlet aerator can efficiently protect a spillway chute surface from cavitation damage due to high-flow velocities. This aerator, unlike conventional ones, is especially preferred at low Froude numbers and with wide spillway chutes to overcome submerged aerator conditions. In this study, the aeration performance of bottom-inlet aerators was investigated for different Froude numbers and ramp heights. Some practical formulas based on experimental and numerical data were obtained to estimate the air entrainment coefficient (and thus the average air concentration) of the bottom-inlet aerators. The findings were compared to some empirical results in published literature for conventional aerators, and then discussed.