Hydroxyl tagging velocimetry in a supersonic flow over a cavity.

Hydroxyl tagging velocimetry (HTV) measurements of velocity were made in a Mach 2 (M 2) flow with a wall cavity. In the HTV method, ArF excimer laser (193 nm) beams pass through a humid gas and dissociate H2O into H + OH to form a tagging grid of OH molecules. In this study, a 7 x 7 grid of hydroxyl (OH) molecules is tracked by planar laser-induced fluorescence.

Hydroxyl tagging velocimetry method optimization: signal intensity and spectroscopy.

The previously demonstrated nonintrusive time-of-flight molecular velocity tagging method, hydroxyl tagging velocimetry (HTV), has shown the capability of operating both at room temperature and in flames. Well-characterized jets of either air (nonreacting cases) or hydrogen-air diffusion flames (reacting cases) are employed. A 7 x 7 OH line grid is generated first through the single-photon photodissociation of H2O by a approximately 193 nm pulsed narrowband ArF excimer laser and is subsequently revealed by a read laser sheet through fluorescence caused by A2sigma+(v' = 3) <-- X2pi(i)(v'' = 0), A2sigma+(v' = 1) <-- X2pi(i)(v'' = 0), or A2sigma+(v' = 0) < or = X2pi(i)(v'' = 0) pumping at approximately 248, approximately 282, or approximately 308 nm, respectively.

Emission spectroscopy for coal-fired cyclone furnace diagnostics.

Using a spectrograph and charge-coupled device (CCD) camera, ultraviolet and visible light emission spectra were obtained from a coal-burning electric utility's cyclone furnaces operating at either fuel-rich or fuel-lean conditions. The aim of this effort is to identify light emission signals that can be related to a cyclone furnace's operating condition in order to adjust its air/fuel ratio to minimize pollutant production. Emission spectra at the burner and outlet ends of cyclone furnaces were obtained.