TIME DEPENDENT PRESSURE MEASUREMENTS ON THE TURBINE-99 DRAFT TUBE

The flow properties of the Turbine-99 draft tube have been subject of much interest by the research community. The first part of the draft tube, i.e. the cone, raised many questions about the pressure re-covery and the time dependence. A complementary experimental investigation was therefore performed in the model test facility of Vattenfall at Älvkarleby, Sweden, to get time resolved wall pressure data. Good agreement with the old measurements is achieved. However, the positions for the T(n) and R(n)-cases are not as expected. The results give a detailed map of the pressure behaviour in this part of the draft tube and are thus of interest for the vali-dation of CFD simulations. The pressure amplitude at the inlet of the draft tube is 1000 Pa. The results also give new information regarding the cases used in the Turbine-99 workshops