Numerical prediction of inflow conditions influence on low-head bulb turbines performance

Abstract

The bulb turbine is widely used in low-head hydropower stations. Due to its relatively short inflow channels, the flow patterns inside the turbines are easily affected by the upstream conditions. The oblique inflow may occur when then the overflow gates are closed, and the oblique angle differs with different installation positions for the turbines. In this paper, the effect of oblique inflow conditions on the turbine performances is numerically investigated for the low-head bulb turbine. Firstly, the effect of inflow conditions on the flow patterns inside the turbine was predicted. Secondly, the hydro performances of the turbines under different oblique angles are discussed. Results show that the oblique inflow can sufficiently affect the turbine flows patterns and turbine performances. A positive oblique angle would lead to a lower efficiency for the turbines compared to a negative oblique angle.