caa a22 4500 606198547 CHVBK 20210128100934.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00348-015-1973-z doi (NATIONALLICENCE)springer-10.1007/s00348-015-1973-z Spray features in the near field of a flow-blurring injector investigated by high-speed visualization and time-resolved PIV [Elektronische Daten] [Lulin Jiang, Ajay Agrawal] In a flow-blurring (FB) injector, atomizing air stagnates and bifurcates at the gap upstream of the injector orifice. A small portion of the air penetrates into the liquid supply line to create a turbulent two-phase flow. Pressure drop across the injector orifice causes air bubbles to expand and burst thereby disintegrating the surrounding liquid into a fine spray. In previous studies, we have demonstrated clean and stable combustion of alternative liquid fuels, such as biodiesel, straight vegetable oil and glycerol by using the FB injector without requiring fuel pre-processing or combustor hardware modification. In this study, high-speed visualization and time-resolved particle image velocimetry (PIV) techniques are employed to investigate the FB spray in the near field of the injector to delineate the underlying mechanisms of atomization. Experiments are performed using water as the liquid and air as the atomizing gas for air to liquid mass ratio of 2.0. Flow visualization at the injector exit focused on a field of view with physical dimensions of 2.3mm×1.4mm at spatial resolution of 7.16µm per pixel, exposure time of 1µs, and image acquisition rate of 100k frames per second. Image sequences illustrate mostly fine droplets indicating that the primary breakup by FB atomization likely occurs within the injector itself. A few larger droplets appearing mainly at the injector periphery undergo secondary breakup by Rayleigh-Taylor instabilities. Time-resolved PIV is applied to quantify the droplet dynamics in the injector near field. Plots of instantaneous, mean, and root-mean-square droplet velocities are presented to reveal the secondary breakup process. Results show that the secondary atomization to produce fine and stable spray is complete within a few diameters from the injector exit. These superior characteristics of the FB injector are attractive to achieve clean combustion of different fuels in practical systems. Springer-Verlag Berlin Heidelberg, 2015 Jiang Lulin Department of Mechanical Engineering, The University of Alabama, Box 870276, 35487-0276, Tuscaloosa, AL, USA aut Agrawal Ajay Department of Mechanical Engineering, The University of Alabama, Box 870276, 35487-0276, Tuscaloosa, AL, USA aut Experiments in Fluids Springer Berlin Heidelberg 56/5(2015-05-01), 1-13 0723-4864 56:5<1 2015 56 348 https://doi.org/10.1007/s00348-015-1973-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-015-1973-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jiang Lulin Department of Mechanical Engineering, The University of Alabama, Box 870276, 35487-0276, Tuscaloosa, AL, USA aut NATIONALLICENCE 700 1- Agrawal Ajay Department of Mechanical Engineering, The University of Alabama, Box 870276, 35487-0276, Tuscaloosa, AL, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/5(2015-05-01), 1-13 0723-4864 56:5<1 2015 56 348