Often, low pressure regions below the runner can be utilized to draw atmospheric air into the turbine during operation. These machines are referred to as auto-venting turbines (AVT) and are particularly cost-effective for injecting large quantities of air into the discharge.
Auto-venting turbine aeration generally consists of three different aeration options, including distributed, central and peripheral aeration.
The interaction between the incoming bubbles and the surrounding water drives the aeration performance by influencing the pressures at the air injection location, the resulting air flows, the dissolved oxygen uptake efficiency, and the turbine performance.
For each project, individual site characteristics, plant design, and desired operation are incorporated into in-house calculation methodologies which account for the necessary bubble modeling to optimize aeration behavior. Based on the predictions, Voith Hydro selects aeration solutions which provide the best value for the customer by maximizing uptake while minimizing the impact on turbine performance and aeration costs.