Large-eddy simulations (LES) of reactive flows are presented, analysing various topics of concern to the combustion community, i.e. multi-regime combustion, solid fuel combustion and nanoparticle synthesis. Regarding multi-regime combustion, a novel burner system is simulated using highly resolved LES and tabulated chemistry. Good agreement with experimental data was observed, while the simulation provides a high-fidelity database for future model development and validation. For solid fuel combustion multi-dimensional flamelet models for LES are developed to represent exhaust gas recirculation and achieve precise pollutant prediction. Relatively new measures to reduce carbon dioxide and nitrogen dioxide emissions, i.e. co-firing of coal and ammonia and the use of a swirl-stabilized low-NO \(_\text {x}\) burner, are investigated numerically and compared against experimental data. Concerning nanoparticle synthesis, a model of amorphous composite nanoparticles is developed for the use as anode material for lithium-ion batteries. Our novel approach pairs the advantages of a spatial-resolving finite volume simulation with detailed models for formation and growth, known from coarse grained molecular dynamics (CGMD) and grants new insights in the overall process of nanoparticle synthesis. More particular, we developed a new multiscale model in the framework of CFD, which features surface reactions, condensation and phase coupling. The Chair of Fluid Dynamics at the University of Duisburg-Essen is pursuing an approach of bundling computational time requirements and applying for them jointly to reduce review efforts