Hydroturbine Venting for Discharge Oxygenation

Tests were conducted on two existing hydroturbines to evaluate turbine venting as a means of oxygenating discharged water. Additions of baffles to the turbine runner hub and to the draft tube wall were made to generate local suction for aspirating air. The effects of these baffles were evaluated in terms of flow rate of induced air, dissolved oxygen uptake and the effect on unit efficiency and output. The results indicated that baffles can be used to increase aspirated air and thus dissolved oxygen uptake, but that there is a related loss in turbine efficiency and capacity.