Effect of phase parameter distribution through channel cross section on the averaged void fraction and condensation process in nonequilibrium bubble flow

A successive approach to description of two-phase non-equilibrium flow, when phase distribution through the channel cross section is already taken into account at the stage of formulation of one-dimensional conservation equations, is applied. Mass fraction of steam in flow is calculated at tolerance of an experimental profile of averaged underheating of the liquid phase by an axial coordinate. Dependences of continuity and energy necessary for closing the system of differential equations are obtained proceeding from representation of underheated boiling medium as a two-layer flow with saturated two-phase near-the-wall layer. A simple dependence of the condensation function on phase distribution by flow cross section is obtained. Improvement of the description of non-equilibrium bubble flow with account of phase parameter distribution through its cross section is shown based on calculations of condensation in underheated flow on an adiabatic section of the channel and based on comparison with experimental data