STUDIES ON THE RELATIONSHIP BETWEEN THE STATISTICS OF VOID FRACTION FLUCTUATIONS AND THE PARAMETERS OF 2-PHASE FLOWS

Based on Bernoulli statistics of bubble dynamics, a model of void Frac tion fluctuations in two-phase Rows is introduced. The model is used t o characterize changes of the intensity of void Fraction fluctuations at various two-phase Row regimes. i.e. bubbly, slug and annular flows. Depending on the applied frequency band, the behavior of the band-pas sed variance of void Fraction Fluctuations changes significantly. At h igh frequencies, the band-passed variance increases monotonously with increasing void fractions, while the variance over the whole frequency range has a prominent maximum. By performing model calculations, the relationship between microscopic two-phase Row parameters and macrosco pic Row quantities has been analyzed.