A Riemann solver for the Drift-Flux Flow Model

Abstract

In this thesis we present a method for calculating exact solutions to a system of equations for two phase flow. This solution is valid for a special case of initial condition called the Riemann problem. The system consists of three hyperbolic conservation laws including gas mass balance, liquid mass balance and total momentum balance. Also, there is a slip relation which relates the true velocities of each phase together. In solving the Riemann problem for the two-phase flow drift flux model, some assumptions have been taken like incompressible liquid. In this thesis the development of the final solution for the Riemann problem is presented. This development includes the star region parameter determination and the exact solution in the rarefaction waves. Using the Riemann exact method to solve the equation systems of hyperbolic conservation laws helps in making a fundamental understanding of the physics and characteristic behavior. Also determining the flow parameters in the interface by the Riemann solution builds a basis for numerical approaches in two phase flow drift flux models.