Comparative analysis of pressure pulsations caused by spiral-vortex structures in the flow part of the hydraulic turbine model

The paper studies the pressure pulsations in the hydraulic turbines flow section arise as a result of vortex structures in non-optimal hydraulic turbine operation regimes. The authors directly compare the approaches to the extraction of synchronous and asynchronous components in pressure pulsation signals, as well as using the decomposition into azimuthal modes. Pressure pulsations were measured using four acoustic sensors while varying the operating regimes of the hydraulic turbine model. The pressure pulsations were compared for the shallow draft tube and the deep draft tube of the hydraulic turbine. It is shown that the level of pressure pulsations is the same for two types of draft tubes. There is no methodological difference in the application of the two approaches to the extraction of pressure pulsations in the flow. The results shall be applicable in the development of new methods for suppressing spiral-vortex structures in non-optimal regimes of operation of hydraulic turbines in order to increase their overall efficiency.