A one-dimensional analytical model has been developed to be used for the linear analysis of density-wave oscillations in a parallel heated channel. The heated channel is divided into a single-phase and a two-phase region. The two-phase region is represented by the drift-flux model. The model accounts for phasic slip and subcooled boiling. The localized friction at the exit of the heated channel is treated considering the two-phase mixture. The exact equation for the total channel pressure drop is perturbed around the steady state. The stability characteristics of the heated channel are investigated using the Nyquist criterion. The marginal stability boundary (MSB) is determined in the two-dimensional thermodynamic equilibrium space parameters, the subcooled boiling number and the phase change number. The predictions of the model agree well with experimental data published in open literature. (1) The effect of thermal equilibrium, equal velocity (homogeneous) model increases the channel steam quality which leads to decrease in localized exit loss coefficient and finally stabilizes the system. (2) The effect of thermal equilibrium, non-equal velocity (drift-flux) model decreases the channel steam quality than the homogeneous model and finally destabilizes the system. (3) The effect of thermal non-equilibrium, equal velocity model (a) decreases the channel steam quality from high subcooled boiling number to a critical value and destabilizes the system, (b) increases the channel steam quality from the critical value to low subcooled boiling number and stabilizes the system. (4) The effect of thermal non-equilibrium, non-equal velocity model (a) decreases the channel steam quality from high subcooled boiling number to a critical value and destabilizes the system, (b) increases the channel steam quality from the critical value to low subcooled boiling number and stabilizes the system and the frequency of oscillation is in good agreement with the experimental data than the other models.

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