Finite volume algorithm to compute dense compressible gas-solid flows

A finite volume scheme is presented that allows the performance of numerica l simulations of a four-equation compressible two-fluid model on unstructur ed meshes. The convective part of the whole set of governing equations is a nonconservative conditionally hyperbolic system. To solve the latter, a fr actional step method is presented, which is based on a splitting of convect ive fluxes. Approximate Roe-type Riemann solvers are used to compute numeri cal convective fluxes. Some computations of shock-tube test cases are prese nted and compared with numerical results of a three-equation model, which a ssumes equal velocities within each phase. A steady computation of a gas-so lid flow in a simple nozzle is described, and an unsteady computation of a dense fluidized bed is also presented, Particular emphasis is given to the preservation of the maximum principle for the volumetric fraction.