Spatio-temporal Characteristics of a Spray from a Liquid Jet in Crossflow
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A liquid jet in a crossflow is often used to as a fuel injection method for combustion systems. Parameters such as penetration and core trajectory are used as characterization for the spray and specification of design criteria for combustor geometry. In addition to penetration and core trajectory, mapping the mass flux in space and time is an important part of modeling evaporation and global equivalence ratio throughout the combustor. Accurate prediction of these spray characteristics allows for a stable and robust combustor design. The break up of a liquid jet in a crossflow is an extremely complex phenomenon in both combination of mechanisms and variability of possible paths progressing from a liquid column to a distribution of individual droplets. In each region separate governing forces control the behavior of the liquid phase. Accordingly, different measurement techniques and different factors must be considered in each region. Presented are the results of measurements using Phase Doppler Analyzer, PDA, and a time resolved, digital, particle imaging velocimetry system, TRDPIV. The measurements include instantaneous and time-averaged liquid phase velocity fields, spray penetration and core location in the near field and far field of the spray resulting from the liquid jet breakup. With the TRDPIV system, the holistic properties of all three segments of a jet in crossflow were acquired with a single measurement. This allowed for comparison of system characteristics across not only individual pieces of one segment of the jet, for example PDA measurements of many droplets in one point of the far field spray, but characteristics across the entire system including the liquid column, near field spray, and far field spray simultaneously in a fashion that allowed for direct comparison between the different segments.
- Masters Theses