Turbulent Flames of Hydrogen

This is an introductory chapter to beginners in the field of turbulent combustion of hydrogen as premixed or diffusion flames. For turbulent hydrogen diffusion flames, global features such as detachment and blow-off velocities as well as flame length are presented along with detailed measurements of temperature and species mass fractions. For turbulent premixed flames of hydrogen, recent measurements of flame speeds and reaction zone thicknesses are shown for a range of conditions within the premixed flame regime. However, detailed measurements of the compositional structure are scarce and yet to become available. The chapter concludes with a discussion of potential approaches to model differential diffusion effects which remain a critical outstanding challenge in facilitating the resurgence of turbulent lean premixed flames of hydrogen in modern power conversion systems.