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Experimental Analysis of the Urea-Water Solution Temperature Effect on the Spray Characteristics in SCR Systems
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 06, 2015 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
One of the favored automotive exhaust aftertreatment solutions used for nitrogen oxides (NOx) emissions reductions is referred to as Selective Catalytic Reduction (SCR), which comprises a catalyst that facilitates the reactions of ammonia (NH3) with the exhaust nitrogen oxides (NOx). It is customary with these systems to generate the NH3 by injecting a liquid aqueous urea solution (AUS-32) into the exhaust. The urea solution is injected into the exhaust and transformed to NH3 by various mechanisms for the SCR reactions.
Understanding the spray performance of the AUS-32 injector is critical to proper optimization of the SCR injection system.
Results were previously presented from imaging of an AUS-32 injector spray under hot exhaust conditions at the injector spray exit for an exhaust injection application. Those results showed substantial structural differences in the spray between room temperature fluid conditions, and conditions where the fluid temperature approached and exceeded 104° C and “flash boiling” of the fluid was initiated. The visualization techniques used in the testing permitted for the first time a quantification of the droplet size distribution changes under flash boiling conditions. However, the flash boiling could only be initiated at very high exhaust temperatures due to the construction of the injection unit.
The spray investigations results presented in this paper follow up on the previous macroscopic imaging work by forcing flash boiling conditions even at reduced exhaust temperatures. The test facility concept and operation are described. The global spray structure changes observed in the previously published hot airflow measurements are confirmed, and conclusions drawn on the relative effects of injection air temperature and injected fluid temperature. Quantified comparisons of the spray atomization characteristics are presented.
Citationvan Vuuren, N., Brizi, G., Buitoni, G., Postrioti, L. et al., "Experimental Analysis of the Urea-Water Solution Temperature Effect on the Spray Characteristics in SCR Systems," SAE Technical Paper 2015-24-2500, 2015, https://doi.org/10.4271/2015-24-2500.
Data Sets - Support Documents
|Unnamed Dataset 1|
- Koebel , M. , Elsener , M. , and Kleemann , M. Urea-SCR: A promising technique to reduce NOx emissions from automotive diesel engines Catalysis Today 335 345 2000
- Schaber , P. , Colson , J. , Higgins , S. , Dietz , E. , Thielen , D. , Anspach , B. , and Brauer , J. Study of the urea thermal decomposition (pyrolysis) reaction and importance to cyanuric acid production American Laboratory August 1999 13 21
- van Vuuren , N. and Sayar , H. High Speed Video Measurements of a Heated Tip Urea Injector Spray SAE Technical Paper 2012-01-1747 2012 10.4271/2012-01-1747
- van Vuuren , N. High Speed Video Measurements of a High Temperature Urea Injector Spray - Comparison of Spray Evolution in Water and AUS-32 SAE Technical Paper 2013-01-2527 2013 10.4271/2013-01-2527
- van Vuuren , N. , Brizi , G. , Buitoni , G. , Postrioti , L. et al. AUS-32 Injector Spray Imaging on Hot Air Flow Bench SAE Technical Paper 2015-01-1031 2015 10.4271/2015-01-1031
- Postrioti et al. Analysis of Global Shape and Sizing of Urea-Water Sprays in a Hot Air Flow Tunnel for the Development of SCR Systems Rouen SIA May 2014
- Zaidi , S. , Altunbas , A. , Azzopardi , B.J. A comparative study of phase Doppler and laser diffraction techniques to investigate drop sizes in annular two-phase flow Chemical Engineering Journal 71 1998 135 143 August 1998
- Aleiferis , P.G. , van Romunde , Z.R. An analysis of spray development with iso-octane, n-pentane, gasoline, ethanol and n-butanol from a multi-hole injector under hot fuel conditions Fuel 105 2013 143 168 July 2012