Impact of Choice of Spray Inputs on Simulations of Urea-Based Selective Catalytic Reduction Systems

Kalyankar, Apoorv; Blessinger, Matthew; Munnannur, Achuth; Liu, Z. Gerald

doi:10.4271/03-13-05-0043

Cited by 3 publications

(7 citation statements)

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“…UWS spray was injected using a pressure swirl atomizer, which had been experimentally characterized in our previous work. 15 A summary of the key characteristics of the injector used is reported in Table 2. UWS dosing was triggered externally so that the laser could be synchronized with the injection event.…”

Section: Methodsmentioning

confidence: 99%

“…32 The meshing strategy was based on findings from our previous work. 15 A predominantly hexahedral mesh was generated with a base mesh size of 5 mm with local refinements on the swirl mixer, the perforated plate and in the spray core region. The total number of cells were ∼2.8 million with 4000 cells on the catalyst inlet face.…”

Section: Methodsmentioning

confidence: 99%

“…More details on the specifications for spray inputs can be found in our previous work. 15 The SCR-thermolysis model of AVL FIRE 32 was used to model the two-step process of water evaporation and urea thermolysis. In the first step, water evaporation is first considered using the multicomponent version of the Abramzon−Sirignano evaporation model.…”

Section: Methodsmentioning

confidence: 99%

“…The engine was operated at each desired speed and load point until the system reached stability with regard to coolant, oil, and DPF outlet temperatures. UWS spray was injected using a pressure swirl atomizer, which had been experimentally characterized in our previous work . A summary of the key characteristics of the injector used is reported in Table .…”

Section: Methodsmentioning

confidence: 99%

“…These simulations are typically based on the Eulerian–Lagrangian framework where exhaust gas is modeled as the continuum phase and spray droplets are modeled as discrete particles. There are numerous studies available in the literature focused on modeling of the relevant physical processes such as UWS spray injection, − spray decomposition, , spray-wall impingement, − heat transfer, , and film formation. , However, there are only a limited number of studies comparing CFD predictions of ammonia uniformity against physical measurements. Fischer et al investigated the impact of the turbulence model and differencing scheme on ammonia uniformity prediction.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Numerical and Experimental Investigation of Ammonia Uniformity in a Compact Selective Catalytic Reduction System

Kalyankar

Backhaus

Munnannur

et al. 2022

Ind. Eng. Chem. Res.

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Spray simulations based on a Eulerian−Lagrangian framework were conducted to predict ammonia uniformity in a urea-based compact selective catalytic reduction (SCR) system and validated against laser absorption tomography measurements at various operating points. Since ammonia distribution profile at the SCR inlet can change over time due to the transient nature of spray-induced wall cooling, changes in spray-wall interaction regime and wallfilm transport, simulations were conducted for a sufficiently long time to achieve quasi-steady temperature and wallfilm distribution profiles on the mixer walls. Simulation runtime was reduced using a database approach and frozen field approximation. Subsequently, one final spray injection cycle was simulated to obtain quasi-steady ammonia distribution at the SCR inlet. Prediction of ammonia rich and lean zones and uniformity index using this approach showed excellent correlation against measured data at various operating points and mixer designs.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical and Experimental Investigation of Ammonia Uniformity in a Compact Selective Catalytic Reduction System

Kalyankar

Backhaus

Munnannur

et al. 2022

Ind. Eng. Chem. Res.

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Breakup dynamics in a pressure-swirl injector for urea-water solution applications: A computational study

Marco-Gimeno,

Asztalos,

Moon

et al. 2024

International Journal of Engine Research

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The co-optimization of in-cylinder combustion and after-treatment technology has become a major aspect in engine design and development, with the goal of meeting the increasingly restrictive emission regulations in the transportation industry. Selective Catalytic Reduction is a robust technology to control the emission of NOx, and the injection of urea in water solution is the exhaust tailpipe is a key aspect of its operation. The proposed work uses high-fidelity Computational Fluid Dynamics to characterize the atomization dynamics of the liquid jet in relevant cross-flow conditions. The study focuses on a commercial low-pressure (9 bar) pressure-swirl injector which is characterized in its internal geometry through high-resolution X-ray micro-computational tomography. The internal two-phase flow has been modeled according to the volume-of-fluid approach in a large eddy simulation framework and validated against near-nozzle X-ray radiography measurement. Moreover, characterizing the breakup dynamics for the swirling hollow cone formation, and assessing the influence of the cross-flow in the breakup dynamics was completed. The results have been reported proposing Re-Oh maps and probability density functions of the spray kinematics. Higher cross-flow momentum generates an increase in the jet intact length and a reduction of the liquid droplet diameters. The axial momentum of the jet is affected by the cross-flow already in the near-nozzle region, determining a relevant deviation of the spray velocities. This work aims to inform the initialization of Eulerian-Lagrangian spray models through the assignment of droplet kinematics and static one-way coupling between volume-of-fluid results and Lagrangian spray parcels, to be used for system-size domain simulations.

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Experimental and Numerical Investigations of Sprays in Crossflow in Aftertreatment Systems

Munnannur¹,

Blessinger²,

Liu³

2021

SAE Technical Paper Series

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Impact of Choice of Spray Inputs on Simulations of Urea-Based Selective Catalytic Reduction Systems

Cited by 3 publications

References 0 publications

Numerical and Experimental Investigation of Ammonia Uniformity in a Compact Selective Catalytic Reduction System

Numerical and Experimental Investigation of Ammonia Uniformity in a Compact Selective Catalytic Reduction System

Breakup dynamics in a pressure-swirl injector for urea-water solution applications: A computational study

Experimental and Numerical Investigations of Sprays in Crossflow in Aftertreatment Systems

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