Analysis of the Flow Field from Connection Cones to Monolith Reactors

Mu, Mingfei; Sjöblom, Jonas; Ström, Henrik; Li, Xinghu

doi:10.3390/en12030455

Cited by 8 publications

(15 citation statements)

References 41 publications

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“…Then, a two-dimensional axisymmetric steady-state incompressible flow model is established to quantitatively analyze the internal flow characteristics of the CN-DTP GPF. The model has been verified by previous research [35,36].…”

Section: Model Formulationsupporting

confidence: 59%

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Study on a New Gasoline Particulate Filter Structure Based on the Nested Cylinder and Diversion Channel Plug

Qiu

et al. 2019

Energies

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Increasingly stringent emission regulations have imposed strict requirements on the particulate matter (PM) from gasoline direct injection (GDI) engines, and the gasoline particulate filters (GPFs) are considered one of the most promising devices for meeting these requirement. To reduce the flow resistance of the GPF, a type of nested cylinder and diversion channel plug (NC-DCP) GPF is designed. It is composed of nested foam metal cylinders and annular diversion channel plugs. The pressure drop and its influencing factors were theoretically studied. The results show that the structural parameters, such as the cylindrical layer spacing and the length-to-diameter ratio, and the pressure drop have trade-off relationships. Moreover, the filtration efficiency is analyzed, and the calculation formula is summarized. The internal flow field distribution and its influencing factors are discussed based on a 2-D axisymmetric simulation. The results show that the exhaust velocity affects the flow field uniformity but does not affect the flow field structure. The pressure drop gradually decreases as the number of nested layers increases, and the positive direction is beneficial to reduce the overall pressure drop. Under different velocities, there is an optimal length-to-diameter ratio to minimize the pressure drop, and the simicircular diversion plug greatly improves the flow uniformity index for the internal flow field of the filter element. ]. Actually, for GDI engines, the emissions may be low on a mass basis (mg/km) but can be very high on a number basis, 10 11 -10 13 #/km (number of solid particles emitted per kilometer), much more than PFI engines, exceeding the particulate number (PN) limit of 6 × 10 11 #/km in China and Europe. Compared with diesel engines equipped with diesel particulate filters (DPFs), modern gasoline engines can emit more PM [12,13].Gasoline particulate filters (GPF) are effective devices for reducing PM emissions. With increasingly stringent emission regulations, research regarding the application of PM filters in GDI engines will become an inevitable trend. The particulate filter must have high filtration efficiency and a long life and satisfy other requirements, and the flow resistance (pressure drop) must be small. The physical characteristics of DPFs have been fully understood and documented [14,15], and these insights can be applied to GPFs. Initially, soot is captured in the wall, known as "deep-bed" filtration. When the filter is fresh, the filtration efficiency (the proportion of particles trapped) is not 100%, but it increases with the mileage. Soot and ash accumulation forms a layer on the filter wall to prevent further penetration of soot into the wall, which is helpful to improve the filtration efficiency. The regeneration of soot can lead to breakage of the soot cake layer, which will reduce the filtration efficiency. However, in most driving conditions and life periods of a vehicle, the filtration efficiency of the GPF is expected to be very high (>90%) [16].The filter element is th...

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Section: Model Formulationsupporting

confidence: 59%

“…For steady-state incompressible two-dimensional flows, the following mass and momentum conservation equations are used to describe the flow (where subscripts i and j represent the directions of the X and Y axes, respectively) [35,36]:…”

Section: Governing Equations Of the Flowmentioning

confidence: 99%

Study on a New Gasoline Particulate Filter Structure Based on the Nested Cylinder and Diversion Channel Plug

Qiu

et al. 2019

Energies

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“…The streamlined (nonuniform rational B-splines, NURBS) cone's improvement of the flow uniformity has been verified from previous experimental results, and the overall pressure drop of the test system can be reduced up to 12% in a special case [37,38]. Simulation results revealed significant changes to the flow structures before the monolith, which illustrates the value of the NURBS cone.…”

Section: Nurbs Cone Applicationsupporting

confidence: 53%

“…The influence of the cone on the monolith flow distribution and the pressure drop has been researched both experimentally and via simulation [38]. However, its influence on the particle distribution has rarely been studied through experiments because it is difficult to obtain a precise and stable test bench, and the use of simulations makes the study more convenient and safer.…”

Section: Nurbs Cone Applicationmentioning

confidence: 99%

“…With the improvement of manufacturing, the NURBS cone can be promoted in the future. Figure 1 shows the particle loading and velocity measurement system, which was similar to the system described in our previous paper [38], contained a gas source system, operation part (monolith and inlet cone), data acquisition system, ventilation system, and an extra particle source system. The gas source system provided the gas needed in the experiment, and included the compressed air, pressure regulator, laminar air flow element, and the ejector dilutor.…”

Section: Nurbs Cone Applicationmentioning

confidence: 99%

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Experimental Study on the Flow Field of Particles Deposited on a Gasoline Particulate Filter

Sjöblom

Sharma

et al. 2019

Energies

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The abatement of particulate matter in gasoline vehicle exhaust has prompted the development of gasoline particulate filters (GPFs). The spatial distribution of the deposited particles inside a GPF has profound implications for its regeneration behavior, ash-induced aging, and multiscale modeling efforts. The connection cones will affect the flow into the monolith and the package structure needed to meet the system space requirements. In this paper, nonuniform rational B-splines (NURBSs) were applied to the cone design to optimize the flow uniformity and particle distribution inside a gasoline particulate filter. NURBS and conventional cones were manufactured using 3D printing, and the velocity profiles and pressure drops were measured under the loading of synthetic particles. The results shows that the cone shape will influence the pressure drop and the velocity profile, which is evaluated as the uniformity index. The test results indicate that better performance is achieved when using the NURBS cone, especially at low particle loads. The results also show that the cone shape (which determines the velocity profile) influences the particle deposition distribution, although the apparent pressure drops are similar. These results are important for exhaust aftertreatment system (EATS) design and optimization, where the NURBS cone can improve flow uniformity, which causes better particle deposition distribution and lower pressure drop.

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NO catalytic performance analysis of gasoline engine tapered variable cell density carrier catalytic converter

Zuo

Yang

Zhang

et al. 2021

Environ Sci Pollut Res

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Improving the flow field uniformity of catalytic converter can promote the catalytic conversion of NO to NO2. Firstly, the physical and mathematical models of improved catalytic converter are established, and its accuracy is verified by experiments. Then, the NO catalytic performance of standard and improved catalytic converters is compared, and the influences of structural parameters on its performance are investigated. The results showed that: (1) The gas uniformity, pressure drop and NO conversion rate of the improved catalytic converter are increased by 0.0643, 6.78% and 7.0% respectively. (2) As the cell density combination is 700 cpsi/600 cpsi, NO conversion rate reaches the highest, 73.7%, and the gas uniformity is 0.9821. (3) When the tapered height is 20 mm, NO conversion rate reaches the highest, 72.4%, the gas uniformity is 0.9744. (4) When the high cell density radius is 20 mm, NO conversion rate reaches the highest, 72.1%, the gas uniformity is 0.9783. (5) When the tapered end face radius is 20 mm, NO conversion rate reaches the highest, 72.0%, the gas uniformity is 0.9784. The results will provide a very important reference value for improving NO catalytic and reducing vehicle emission.

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Analysis of the Flow Field from Connection Cones to Monolith Reactors

Cited by 8 publications

References 41 publications

Study on a New Gasoline Particulate Filter Structure Based on the Nested Cylinder and Diversion Channel Plug

Study on a New Gasoline Particulate Filter Structure Based on the Nested Cylinder and Diversion Channel Plug

Experimental Study on the Flow Field of Particles Deposited on a Gasoline Particulate Filter

NO catalytic performance analysis of gasoline engine tapered variable cell density carrier catalytic converter

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