Spray characteristics of a urea solution injector and optimal mixer location to improve droplet uniformity and NOx conversion efficiency for selective catalytic reduction

Oh, Jungmo; Lee, Kihyung

doi:10.1016/j.fuel.2013.11.032

Cited by 55 publications

(24 citation statements)

References 7 publications

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“…The mixing and evaporating UWS decomposes into ammonia, which is the reducing agent needed to transform NOx to N2 at the catalyst. Usually, a low injection pressure (~ 10 bar) UWS is injected either directly into the exhaust pipe [1,2] or to a mixer or high-swirl generating mixing device [3,4]. In the present study, the former type of SCR system is analyzed.…”

Section: Introductionmentioning

confidence: 99%

Mixing and evaporation analysis of a high-pressure SCR system using a hybrid LES-RANS approach

Kaario

Vuorinen

Zhu

et al. 2017

Energy

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A hybrid Large Eddy Simulation (LES)-Reynolds-Averaged Navier-Stokes (RANS) method (HLR) has been applied to simulate an engine related selective catalytic reduction (SCR) system. Typical SCR systems utilize low pressure urea injection together with a mixer for vapor field homogenization. Simultaneously, it is also desirable to reduce spray-wall interaction to avoid urea crystallization. The present study considers an SCR system where a high pressure (150 bar) urea spray is injected towards hot exhaust gases in exhaust pipe. The system has been shown to work well in a previous experimental study but detailed characterization of the system is missing. The novelty of the present study rises from: 1) the creation of phase diagrams with single droplet simulations that predict the optimum operation regions for the SCR system, 2) validation of the HLR method in a high Reynolds number (= 49,900) compressible pipe flow, 3) the use of HLR simulations in an engine SCR system for the first time, and 4) the detailed characterization of the present SCR system. As a result of the study, new non-dimensional timescale ratios are proposed to link the droplet size and liquid injection velocity to the exhaust pipe dimensions in future SCR systems.

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Section: Introductionmentioning

confidence: 99%

Mixing and evaporation analysis of a high-pressure SCR system using a hybrid LES-RANS approach

Kaario

Vuorinen

Zhu

et al. 2017

Energy

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show abstract

“…Spiteri and Dimopoulos Eggenschwiler [19] described an apparatus based on Mie scattering and particle image velocimetry for investigating the atomisation characteristics of a pressure driven urea-water injector. Oh and Lee [16] employed laser diagnostics and a high speed camera to determine the optimal injector/ mixer distance for urea-water injection and investigate the distribution of droplets. The study was conducted within a transparent manifold system simulating a real exhaust pipe.…”

Section: Introductionmentioning

confidence: 99%

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

Postrioti

Brizi

Ungaro

et al. 2015

Fuel

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“…Kuhnke first established a spray/wall effect model and improved the urea injection accuracy [11]. During the collision process, droplets were divided into four states: deposition, splash, rebound, and thermal decomposition [12][13][14][15]. Birkhold extended the four hitting areas in the model to six, increasing the the physical length of canning structure is the best way to reduce the temperature loss, and the compact structure of the exhaust gas after-treatment system can better adapt to the spatial arrangement of various vehicles.…”

Section: Introductionmentioning

confidence: 99%

Application Study on a New Hybrid Canning Structure of After-Treatment System for Diesel Engine

et al. 2020

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Based on the airflow rotation concept, a new packaging structure was designed to meet the performance requirements of China-VI stage emission regulations. The new structure is a hybrid structure of spiral space with small blades and conical plates. The Computational Fluid Dynamics (CFD) simulation was used to analyze the velocity uniformity and ammonia uniformity of the flow field, and the results showed that velocity uniformity and ammonia uniformity were higher than 0.95, and the possibility of crystallization risk was very low. The actual performance of the new structural prototype was verified by means of engine bench testing. The test results were excellent and the conversion efficiency reached 0.96. The new selective catalytic reduction (SCR) urea mixed structure design greatly improved the conversion efficiency of the after-treatment system and has excellent anti-crystallization performance.

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Spray characteristics of a urea solution injector and optimal mixer location to improve droplet uniformity and NOx conversion efficiency for selective catalytic reduction

Cited by 55 publications

References 7 publications

Mixing and evaporation analysis of a high-pressure SCR system using a hybrid LES-RANS approach

Mixing and evaporation analysis of a high-pressure SCR system using a hybrid LES-RANS approach

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

Application Study on a New Hybrid Canning Structure of After-Treatment System for Diesel Engine

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