Computational fluid dynamics (CFD) has been firmly established as a fundamental discipline to advancing research on energy engineering. The major progress achieved during the last two decades, both in software modeling capabilities and hardware computing power, has resulted in a considerable and wide spread of CFD interest among scientists and engineers. Numerical modeling and simulation developments are increasingly contributing to the current state of the art in many energy engineering aspects, such as power generation, combustion, wind energy, concentrated solar power, hydro power, gas and steam turbines, fuel cells, and many others. This Special Issue on "CFD Applications in Energy Engineering Research and Simulation" aims to provide the latest significant advances in the applications of computational fluid dynamics in energy engineering.