Simultaneous Temperature and Velocity Diagnostic for Reacting Flows

A diagnostic technique is proposed for measuring temperature and velocity simultaneously in a high temperature reacting flow for aiding research in propulsion. The technique involves seeding particles of a ceramic thermographic phosphor into the flow and illuminating them with two overlapping pulsed laser sheets. Laser-induced luminescence from the particles will be measured to obtain temperature from its effects on luminescence lifetime. Velocity will be obtained simultaneously from the same particles using conventional particle image velocimetry (PIV). Each of the two diagnostics will employ a separate CCD camera that captures a pair of images separated by a short delay. For the thermometry technique, pixel intensity ratios of the delayed to the undelayed images will be related to temperature via a calibration function. In the PIV technique, particle displacements between the images will be obtained using conventional interrogation window techniques with cross-correlation. The proposed diagnostic is expected to enable spatially and temporally correlated measurements of two key variables in combustion modeling that cannot be obtained in most high temperatures flows using currently available methods. The phase I effort will demonstrate feasibility measurements in a flame.