This paper is concerned with the modeling and analysis of multi-dimensional aspects of subcooled boiling. Specifically, a two-dimensional model of two-phase flow in a circular boiling channel is discussed, including the modeling concepts used for various closure laws, as well as the results of model testing and validation. A new correlation for the coolant enthalpy at void detachment point in developing flows is proposed, and various effects are investigated of unsteady flow and heat transfer conditions on void distribution in a boiling channel.