A method of flow measurement in draft tube

The measurement of flow rate is the most difficult and challenging part of the hydropower station tests. This paper provided a method based on differential pressure which has high precision, less cost and convenience. Three-dimensional numerical simulation was performed for NTNU (Norwegian University of Science and Technology) model turbine in steady conditions, meanwhile a new expression of flow rate and differential pressure of bent elbow was proposed. It was proved that the pressure difference method could be applied to the real-time flow measurement in draft tube and its error was in an acceptable range.