LASER SELECTION CRITERIA FOR OH FLUORESCENCE MEASUREMENTS IN SUPERSONIC COMBUSTION TEST FACILITIES

The limitations of the application of dye laser and narrow-band tunable KrF excimer laser systems to OH planar laser-induced fluorescence measurements in supersonic combustion test facilities are examined. Included in the analysis are effects of signal strength, collisional quenching, beam absorption, and fluorescence trapping on achievable measurement accuracy using several excitation and detection options for either of the two laser systems. Dye based laser systems are found to be the method of choice for planar imaging when the line integral of OH concentration along the incidence or detection paths is less than 10(16) cm/cm3, whereas the KrF based systems provide significant reduction in measurement ambiguity when either concentration line integral is in excess of 10(16) cm/cm3.