Affiliations: Department of Mechanical Engineering, Niigata
University, 8050 Ikarashi 2, Niigata, 950-2181, Japan
Abstract: The structure of hydrogen jet flame diluted by CO_2 in air flow is
studied by various visualization techniques, such as schlieren, direct
photograph, tracer injection and reactive Mie scattering method, which allow
understanding of the influence of CO_2 on the characteristics of the hydrogen
jet flame. The experimental result indicates that the flame structure consists
of laminar fuel jet and surrounding reaction zone near the nozzle exit. When
the CO_2 fraction is increased, the width of the fuel jet grows and the reaction
zone is reduced in size. These observations are further confirmed by
quantitative measurements of temperature and velocity fields in the flame,
which are evaluated by thermocouple and particle image velocimetry (PIV),
respectively. These results indicate that the flame temperature is decreased
and the flow rate of the fuel jet is increased by the influence of diluents,
which are due to the reduced calorific value and larger density of fuel,
respectively.