Numerical simulation of swirling flow modes in a model of a hydraulic turbine and a draft tube
A.V. Minakov1,2, D.V. Platonov1,2, A.V. Sentyabov1,2
1Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Siberian Federal University, Krasnoyarsk, Russia
Keywords: pressure pulsations, Francis turbine, re-connection, modeling, hydroelectric power station
Abstract
The influence of asymmetric boundary conditions on flow regimes in a model hydraulic turbine has been investigated. The curved draft tube is shown to have almost no effect on the vortex structure, preserving such a phenomenon as the re-connection of the vortex core. The axial and tangential velocity profiles also remain unchanged. There is a change in pressure pulsations, despite the similarity of the average values and the unsteady vortex flow pattern. In the case of an asymmetric model, the pressure pulsation is higher than for a symmetric model. This may indicate a superposition of pulsations, caused by the rotation of a precessing vortex core, with generated longitudinal (synchronous) pressure fluctuations.
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