The Drift Flux Model in the ASSERT Sub-Channel Code

Abstract

The ASSERT subchannel code has been developed specifically to model flow and phase distributions within CANDU fuel bundles. ASSERT uses a drift-flux model which permits the phases to have unequal velocities, and can thus model phase separation tendencies which may occur in horizontal flow. The basic principles of ASSERT are outlined, and computed results are compared against data from various experiments for validation purposes. The paper concludes with an example of the use of the code to predict critical heat flux in CANDU geometries.