The technique of calculation of non-equilibrium two-phase flows in pin bundles using quasi-two-dimensional approaches and subchannel approximation

In this paper a theoretical approach to heat bundle parameter calculation in boiling reactors which resulted in the use of the subchannel approximation procedure with the verified system of equations for the subchannels is described. The system of equations is written for the drift flux model of the two-phase non-equilibrium flow in the quasi-two-dimensional approximation. Recommendations for calculating the distribution parameters included in the quasi-two-dimensional problem formulation are given. Combining the subchannel approximation with the quasi-two-dimensional approach helps to keep up acceptable calculation precision for the bundles with relatively large subchannels when the cross-sectional phase parameter distribution for each subchannel must be taken into consideration. Some calculation results are presented