A MIXTURE MODEL FOR THE SIMULATION OF THERMAL-HYDRAULICS BUBBLY FLOW
Two-phase bubbly flow is widely associated with the nuclear thermal-hydraulics for future reactors design. In many cases within such reactors, the relative velocity between the two-phases is crucial in operational and safety analysis. More insights from either mathematical or numerical investigations are desired to better understand and predict the relative velocity behavior. The relative velocity prediction has been getting more interest as a tool towards accurate modeling of two-phase bubbly flows. For this purpose, a non-equilibrium two-phase flow model based on mixture formulations is considered in this paper. We present our recent effort in simulation two-phase flows using a third order interpolating wavelet transform based on a threshold operator. This allows a sparse representation of the complete numerical solution in every time step where
the flux derivatives are approximated by the standard WENO scheme. The model equations and numerical computations are tested and verified through gas-liquid two-phase mixtures by means of thermal-hydraulics tests. These simulations examine the effect of high and low relative velocities at different gas void fractions. The computations demonstrated good mesh convergence simulations adapting mixture formulations for twophase bubbly flows. Quantitative performance of simulations are also presented to further investigate the
model equations by comparing the results with different Riemann solvers based numerical methods. The same trend is also displayed for two-dimensional test cases demonstrating the capabilities of multiresolution techniques to resolve non-equilibrium two-phase flow equations within nuclear reactors.