Spray Characterization of the Urea-Water Solution (UWS) Injected in a Hot Air Stream Analogous to SCR System Operating Conditions

Payri, Raúl; Moreno, Armando

doi:10.4271/2019-01-0738

Cited by 15 publications

(21 citation statements)

References 16 publications

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“…The graph presented in Figure 5 shows the average (for frames between 10 and 12 ms after start of injection, and for five injections) spray visualisation angle measured for both UWS and water at all considered injection pressures. It may be observed that for both liquids the spray angle increases with injection pressure, which is consistent with results shown by other researchers for similar injection parameters [24,26]. When considering differences between the studied fluids it can be seen that the visualization angle determined for UWS was higher than for water for all considered injection pressures.…”

Section: Spray Visualization Anglesupporting

confidence: 90%

“…Different optical properties could be compensated (e.g., by using stronger light to illuminate the spray or by using a different intensity threshold value to separate the spray cloud from the background), but as stated earlier, the idea behind this work was to compare the sprays using the same set-up and the same conditions, which includes the data processing as well. Especially as setting the intensity threshold value for It may be observed that for both liquids the spray angle increases with injection pressure, which is consistent with results shown by other researchers for similar injection parameters [24,26]. When considering differences between the studied fluids it can be seen that the visualization angle determined for UWS was higher than for water for all considered injection pressures.…”

Section: Spray Visualization Anglesupporting

confidence: 88%

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Characteristics of Water and Urea–Water Solution Sprays

et al. 2019

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In spray studies related to selective catalytic reduction (SCR) systems a common approach is to replace the urea–water solution (UWS) with pure water, even though there is very limited detailed information on the spray properties for these two liquids obtained under the same conditions using the same experimental equipment. Neither is it known how the possible differences in spray properties influence computational fluid dynamics (CFD) simulations. In this study, besides the flow characteristics, we compare both global and local spray parameters measured for UWS and pure water in the same conditions. To our knowledge, this is the first study which examines the influence on the injection process of replacing UWS with water over such a wide range. Moreover, the influence of different spray properties on CFD simulations is also examined. The experimental studies showed differences in almost all considered spray parameters. Moreover, different spray behaviour was noticed in terms of primary break-up. One important finding is that water and UWS sprays do have a similar Sauter mean diameter, but at the same time the droplet size distribution is considerably different. The simulation results indicated noticeable differences in terms of wall film formation; nevertheless, the overall mixing performance was not significantly affected.

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Section: Spray Visualization Anglesupporting

confidence: 90%

Section: Spray Visualization Anglesupporting

confidence: 88%

Characteristics of Water and Urea–Water Solution Sprays

et al. 2019

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“…The first step was to define the general shape of the spray that would assist in the definition of the locations for the near-field visualization windows, ensuring that they are within the spray boundaries. Besides, this methodology is often used for determining other global spray parameters like the spray penetration and the angle, as was reported by Payri et al [15].…”

Section: Contour Determinationmentioning

confidence: 99%

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

Payri

Bracho

Gimeno

et al. 2019

Experimental Thermal and Fluid Science

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“…Even though UWS sprays occur along with the crossflow, they are usually examined in quiescent environments. Macro-and microscopic optical spray measurements in crossflow conditions were presented by Payri et al [12]. The spray shape was barely altered by the change in the flow temperature (up to 350°C).…”

Section: Introductionmentioning

confidence: 96%

“…These devices become a crucial enhancement in SCR development, allowing for continuous, long-term tests in precisely controlled conditions without the necessity for actual engine applications. The flow rigs can be designed also for UWS spray visualisation [8,9,12,13]. Spray investigations in flow conditions are necessary to validate numerical models and for evaluation of the consequences of droplet-flow-related phenomena.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the flow rig for UWS spray examination in exhaust system-relevant conditions

Górka¹,

Kaźmierski²,

Kapusta³

2021

Combustion Engines

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In the present study, a flow rig with optical access intended for spray investigations in exhaust system-relevant conditions was analysed in terms of flow and temperature in the spray area using numerical simulations. The operation of the rig was examined for a wide range of exhaust mass flow rates, temperatures and various forms of UWS (urea-water solution) spray plumes. The locations of the injector and thermocouple were verified. Both conventional and flash-boiling injections were considered to assess the effect of the interaction of sprays with a gas flow. The results showed a highly uniform flow in the visualisation area, with only minor fluctuations near the walls. A similar observation was carried out for the temperature distribution. It was found that the extreme operating conditions caused substantial deformations of the spray plumes. However, the selected injector location allowed us to properly observe the spray formation regardless of the flow conditions. The study showed that the examined test rig enabled reliable spray investigations for a wide range of operating points.

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Spray Characterization of the Urea-Water Solution (UWS) Injected in a Hot Air Stream Analogous to SCR System Operating Conditions

Cited by 15 publications

References 16 publications

Characteristics of Water and Urea–Water Solution Sprays

Characteristics of Water and Urea–Water Solution Sprays

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

Numerical analysis of the flow rig for UWS spray examination in exhaust system-relevant conditions

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