Author(s): Fei Ma; Jian-Hua Wu; Kunpeng Su; Jianrong Xu
Linked Author(s): Fei Ma, Jianhua Wu
Keywords: 3D-aerator; Lateral enlargements; Air concentration; Lateral cavity length; Water fins
Abstract: Aerator is an effective element to entrain air into flow for protecting spillways from cavitation damage. However, many spillway side wall had been damaged due to lack of air entrainment near the side wall surface. As a result, 3D-aerator has been introduced for protecting both of bottom and side surfaces of spillways. The present study investigates the performance of a 3D aerator with lateral enlargement for discharge tunnels on a physical model. Results with respect to water fins height, air concentration distribution and lateral cavity length are presented in the form of non-dimensional plots. From this study, the non-dimensional water fin height increases as the lateral enlargement width, the bottom cavity length, approach Froude number. It is also found that the lateral air entrainment can protect the side walls of discharge tunnel from cavitation damage. Based on theoretical analysis, the lateral cavity length is determined by the approach flow Froude number and the ratio of lateral enlargement width to channel width. The paper also presents an empirical expression of lateral cavity length for the 3D aerator with lateral enlargements.