Regimes with periodical pressure pulsation in Francis draft tube

The paper reports on results of the experimental study of flow and pressure pulsations in a laboratory model of the draft tube of Francis-99 hydro turbine over a broad range of operating regimes. A novelty is the rapid prototyping and 3-d printing of the inflow swirl generators that makes it possible to acquire rapidly a large amount of experimental data for a variety of designs and operating conditions. The frequency characteristics of flow and the phase-average pressure distribution in draft tube cone have been measured with the aid of special acoustic sensors.