Mikro-Makro-Wechselwirkungen in strukturierten Medien und Partikelsystemen "Numerical Computation of Heat and Mass Transfer in Fluidzed beds with spray Injection"

Fluidized bed spray granulation is a process used for the production of granular high-quality, low-dust, and low-attrition solids originating from liquid products. The modeling of the problem is obtained by the balance of the mass and energy of the air, of the solid as well as of the liquid contained in the fluidized bed. The balance inside the fluidized zone delivers a hyperbolic and parabolic partial differential equation for each balance variable. The balance variables are understood as functions of space and time. The model equations of the problem are a complicated system of partial differential equations. At present we are solving the full system with zero Neumann boundary conditions at the wall surface and Dirichlet boundary conditions at the bottom surface. For the full system we obtained positive results in two dimensions for the temperature and concentration distributions inside the fluidized bed using a standard Galerkin method for the spatial discretization with discrete boundary conditions and using the implicit Euler method for the time discretization. Now we want to compare these results with experimental results. Also we want to optimize the computation by using partitioning methods to compute non-stiff parts of the problem by explicit time stepping. We are studying the construction of invariant rectangles and stability for this problem. Later we are interested in 3D simulations. We want to use different degrees of net depositions for the liquid drops.