Fluid dynamics in energy technology applications
Solid fuels can be converted into heat and power in fixed or fluidized fuel beds. Even though the use of these combustion techniques is widespread, detailed knowledge of the combustion behaviors in such beds, which could be used to optimize performance (especially that of fixed-bed boilers), is lacking. Computational fluid dynamics (CFD) is useful in the optimization and in obtaining detailed knowledge of the fuel conversion process, regarding parameters such as burnout, emissions, fuel flexibility, and material wear. However, for such simulations to be viable, computationally efficient models that can handle the most important features of the fuel conversion processes are needed. In this project, mathematical models and numerical techniques applicable to CFD simulations of fixed and fluidized beds are developed and optimized. Special consideration is directed to the interactions between momentum, heat and mass transfer on the level of both single and multiple particles in the bed. The overall long-term aim is to derive computationally viable submodels for use in industrial scale simulations of energy technology applications.