Extended equivalent linearization method for density wave instability analysis.

Abstract

An equivalent linearization method has been introduced for density-wave oscillation analysis. Unlike the frequency domain approach with linearized equations assuming an infinitely small amplitude, the present method can deal with large amplitude oscillations with the nonlinearity effect on limit cycle amplitudes taken into account in the frequency domain. Equivalent linear equations have been derived based on a one-dimensional separated flow model. A profile fit model was adopted for subcooled boiling. The characteristics of the equivalent linear equations and factors to limit the amplitudes were phenomenologically examined. Analyses of the experimental data by Saha et al. using the present method revealed that, given an appropriate set of two-phase flow correlations, the equivalent linearization method can predict limit cycle amplitudes after instability initiation as well as the stability boundary.