Laser diagnostics for urea-water solution spray characterization

Abstract

Abstract. In this study, we summarize the laser techniques used for urea-water solution (UWS) spray characterization at the Institute of Heat Engineering (ITC), Faculty of Power and Aeronautical Engineering at Warsaw University of Technology. In presented studies several techniques for both, global and local spray characterization were used. Shadowgraphy-based long distance microscopy was used to visualize individual droplets and primary breakup. High speed imaging of Mie scattering (scattering on the gas-liquid interface) signal was used for global spray characterization. Combination of LIF (Laser Induced Fluorescence) and Mie scattering allowed to determine qualitative droplet size distribution across the whole spray cloud. The structured illumination technique used to modulate laser light sheet allowed to minimize the effects of multiple scattering in detection of Mie signal, what indicated huge potential of this technique in characterization of UWS sprays. The results presented here prove the importance of laser diagnostics in SCR systems development.

Investigation of the urea-water solution atomization process in engine exhaust-like conditions

“…Injection pressure of 8 bar has a higher droplet probability in the range between 80 μm and 180 μm and for droplets with diameters above 200 μm the tendency reverts, depicting a higher droplet probability for the injection pressure of 4 bar. The overall values obtained in this work were in the same order of magnitude as those found by other authors[8,14,24,25].…”

Characteristics of Water and Urea–Water Solution Sprays

“…These include both spray formation as well as spray-wall interaction. In many studies available in the literature, UWS is replaced with pure water [3][4][5][6][7][8][9]. For preliminary studies, such an approach seems to be justified since the physical properties influencing spray behaviour, specifically surface tension and viscosity, are similar for these two liquids.…”