Applicability of the CONTAIN Code Heat and Mass-Transfer Models to Asymmetrically Heated Vertical Channels

Abstract

The applicability of the empirical approach in the CONTAIN computer code for the simulation of induced flow and heat transfer in asymmetrically heated, vertical parallel-plate channels is investigated. The physical situation is related to containment cooling in the Westinghouse AP600 reactor. The countercurrent flow of air in the channel is induced by the thermal buoyancy force. In CONTAIN, the heat and mass transfer analogy (with Sherwood number calculated based on an empirical Nusselt number correlation for fully developed flows), including the film theory correction for high mass transfer, is used to calculate film evaporation. The buoyancy-induced flow is calculated through coupled solutions to lumped-parameter mass, energy, and momentum equations. The CONTAIN predictions are first compared with the Purdue results of a more detailed two-dimensional model under identical conditions in a simple parallel-plate channel. Then the CONTAIN predictions are compared with the results of the Purdue two-dimensional model and with data for two selected (forced and free convection) tests performed in the Westinghouse Large Scale Test (LST) Facility. Analyses show that the CONTAIN-calculated Sherwood numbers, the total heat fluxes, the steam mass fraction, and the bulk velocity in the channel are comparable to the two-dimensional Purdue investigations for the parallel-plate simulations and for the conditions of the Westinghouse LST Facility.