Mass transfer studies across ventilated hydrofoils: A step towards hydroturbine aeration

摘要: Abstract The water discharged by hydropower facilities is a matter of increasing concern due to poor downstream quality. use auto-venting hydroturbines has been suggested as one the best ways mitigate low dissolved oxygen levels in water. Much design currently performed with computational fluid dynamics (CFD) simulations. However, there little information available test and verify performance these simulations regarding gas transfer bubble size distribution. This paper investigates tunnel test-bed for CFD an hydroturbine through ventilated hydrofoil. Bubble distributions are measured shadow imaging technique found have Sauter mean diameter 0.9 mm reference case. Higher liquid velocities, lower airflow rate higher angle attack all resulted greater number small bubbles weighted size. Bubble-water disturbed equilibrium technique. model Azbel (1981) utilized characterize film coefficient transfer, scaling reflect fact that characteristic turbulent velocity replaced cross-sectional velocity. value stay constant at particular hydrofoil configuration while it varied over narrow range 0.52–0.60 different angles attack. suggests appropriate flow possibly other situations. These results can be used investigators their against known important similarities hydroturbine.