Quantitative flow visualization

A method for visualizing a range of flowfield parameters including temperature, velocity, species concentrations, pressure, and, in the case of two-phase flows, droplet or particle distributions is established. Ideally these techniques should be applicable to nonreacting and reacting flows, including plasmas. Most of the work has utilized planar laser induced fluorescence (PLIF), except for particle visualization which uses planar Mie scattering (PMS). The approach and some representative results for temperature and velocity are given. An overview of the fluorescence based temperature sensing strategy, and representative results for instanteous temperature contours in a vertical plane in a rod stabilized, premixed CH4-air flame are provided. A schematic diagram of the two frequency strategy for monitoring velocity, also based on fluorescence, is shown and as are sample results for the axial velocity component in a subsonic, room temperature nitrogen roundjet. For temperature measurements, the light source is a pulsed dye laser system, yielding tunable output near 226 nm. For velocity visualization a tunable CW Art laser is used operating on a single axial mode near 515 nm.