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Fakulteta za strojništvo, Ljubljana (FSLJ)
  • Simultaneous analysis of structural and pressure pulsations of cavitated vortex core in a Francis turbine
    Rus, Tomaž ...
    ǂA ǂcomplex behaviour of a cavitated vortex core in a fully developed turbulent flow was investigated. By the position of the cavitated vortex in a draft tube of a Francis turbine, patterns in time ... and space are formed. Experiment was performed on a model Francis turbine with specific rotational speed n[q] = 80 at various integral parameters of the machine. A simultaneous analysis of pressure and structural fluctuations of cavitated vortex core in the draft tube was performed. The level of grey intensity in space and time forms scalar patterns which can be observed by means of a computer-aided visualization. By successive digitisation of snapshots, the distribution of the cavitated vortex core, in restricted areas simultaneous scalar time series were generated. Simultaneous measurement of pressure pulsation was performed in two locations of the turbine draft tube in a manner that enables experimental modelling of mutual dependence of structural dynamics of cavitated vortex core and pressure pulsation in the turbine draft tube. Local dynamics was correlated with integral characteristics of the observed process. A comparison between simultaneously captured pressure pulsation and scalar fluctuation enables determination of correlation dependencies. The relationship of both measured quantities is presented with cross-correlation functions for the entire observed region at different turbine operational regimes. The significant correlation of both observed quantities is expressed and the causal relationship, as well, presented by phase shifts, periodicity, and damping coefficients of correlation functions.
    Vir: [Advances in hydro-science and -engineering [Računalniška datoteka]. Vol. IV, Proceedings] (PAP_231.pdf (9 str.))
    Vrsta gradiva - prispevek na konferenci
    Leto - 2000
    Jezik - angleški
    COBISS.SI-ID - 3965979

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