A Fully Implicit Numerical Scheme for Simulation of Two Phase Flow in a Vertical Channel Using the Drift Flux Model

In this paper, a two phase flow in a vertical channel is simulated implicitly using the drift flux model. Unconditional stability and also second order accuracy in time are advantages of the fully implicit approach. So far, Newtonʼs method has been used for solution of the nonlinear system of equations arising from the fully implicit discretization of the physical field equations. Lack of convergence robustness arising from the weak initial guess and the Jacobian matrix construction, have created some difficulties for researchers. In this article, using the SIMPLE algorithm, a fully implicit model for simulation of the two phase flow is provided. The model does not have the two mentioned drawbacks of the Newtonʼs method. For a wide range of conditions, the key thermo-hydraulics parameters obtained by the present model are in good agreement with both the experimental data and the RELAP code results. Based on the performance assessment, the model has a second order accuracy in time and the time step need not be limited to maintain stability.