Performance of a two-phase natural circulation in a rectangular loop

An analytical solution for the loop mass flow rate for a two-phase natural circulation in a rectangular loop is derived. The cases with saturated inlet flow and sub-cooled inlet flow are considered. The loop mass flow rate was obtained as a function of geometric parameters of the loop, frictional loss coefficient, pressure, heat input, and inlet sub-cooling. An optimal configuration for the natural circulation was suggested in terms of geometric parameters and heat input for a stable inherent safe operation of the two-phase natural circulation loop.