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Experimental validation of evaporating urea-water sprays at elevated temperature and pressure

Lieber, Christian; Koch, Rainer; Bauer, Hans-Jörg

Abstract (englisch):
Selective Catalytic Reduction (SCR) is a standard technology for reducing nitrogen oxide (NOx) emissions of diesel engines. It is usually realised by injection of liquid urea-water-solution (UWS) into the hot exhaust gas. One major challenge of the design is to avoid deposits, especially melamine complexes, which may compromise the operation of the catalyst. Consequently, the proper understanding of the spray evaporation of UWS is key to successfully implement the SCR technology.
The main objective of this paper is to present a validation experiment of evaporating urea-water sprays under realistic operating conditions at elevated temperature and pressure. The experimental configuration is based on a twin-fluid atomizer for injecting UWS into a hot pipe flow. Microscopic imaging was applied in conjunction with Particle Tracking Velocimetry to record droplet size and velocity distribution profiles. Using this approach, droplets of a diameter as small as 4 μm and a velocity of up to 250 m/s could be detected successfully at operating conditions of the gaseous phase of up to 773 K and 0.24 MPa.
The evaluation of droplet data at different positions downstream of the atomizer revealed details of the evaporation characteristics of urea-water solution. ... mehr



Zugehörige Institution(en) am KIT Institut für Thermische Strömungsmaschinen (ITS)
Publikationstyp Vortrag
Jahr 2019
Sprache Englisch
Identifikator KITopen-ID: 1000098224
Veranstaltung 6th International Symposium on Modeling of Exhaust-Gas After-Treatment (2019), Bad Herrenalb, Deutschland, 08.09.2019 – 10.09.2019
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