Emission and Absorption Measurement in Enclosed Round Jet Flames

This paper describes a procedure to measure the emission and the absorption of an axis-symmetric flame enclosed in a refracting housing. The radial absorption coefficient as well as the emission is obtained from line-of-sight integrated measurements using an improved tech- nique. The procedure is based on typical Abel-type transforms found in literature. Their common constraint, that measurements have to be taken along parallel rays through the flame, is not fulfilled in many situations. This problem is addressed by ray tracing techniques which identify the path of the measured radiation. On this basis, a discretized reconstruction scheme is developed that con- volutes the radiation path with the axis-symmetric flame. Using this tool, the radial absorption and emission coefficients can be computed from measurements of flames with arbitrary optical density. The method is demonstrated on a laminar hydrogen-oxygen jet flame at elevated pressure. The UV absorption and emission of the OH radical is measured and compared with data from numerical simulations. The impact of the enhancement is discussed.     «

This paper describes a procedure to measure the emission and the absorption of an axis-symmetric flame enclosed in a refracting housing. The radial absorption coefficient as well as the emission is obtained from line-of-sight integrated measurements using an improved tech- nique. The procedure is based on typical Abel-type transforms found in literature. Their common constraint, that measurements have to be taken along parallel rays through the flame, is not fulfilled in many situations. This pr...     »