Measurement and Prediction of Filtration Efficiency Evolution of Soot Loaded Diesel Particulate Filters

Zhong, Danhong; He, Shizhu; Tandon, Pushkar; Moreno, M Mendez; Boger, Thorsten

doi:10.4271/2012-01-0363

Cited by 27 publications

(18 citation statements)

References 18 publications

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“…In addition to the orientation of the thermophoretic force with respect to the flow direction, the impact of the magnitude of both the temperature gradient and the flow velocity on soot capture was investigated for the four cases: three temperature gradients (3500, 7000, and 14 000 K/m), and three superficial gas velocities (0.005, 0.11, and 0.22 m/s, corresponding to average flow rates of 0.0125, 0.275, and 0.55 m 3 /s, respectively) were used. The middle range value of 0.11 m/s is a typical velocity usually reported for a DPF . Although the temperature gradients and temperature used are larger than the ones usually encountered during normal gas exhaust filtration operations, they represent a worst‐case scenario for the impact of thermophoresis.…”

Section: Methodsmentioning

confidence: 97%

“…Given the multi‐scale nature of the transport phenomena involved and their interactions, numerical modelling is considered a useful approach for developing an in‐depth understanding and for designing better filters. Since the introduction of DPFs in the early 1980s, a large body of numerical investigations have been carried out to study transport and catalytic reaction phenomena, gas flow and back pressure, soot filtration, and thermal stresses at three different length scales inside a DPF: the porous wall, the filter channel, and the entire DPF volume . Thorough and comprehensive reviews of the various numerical models, their development over the years, and their validation with experiments can be found in the recent literature …”

Section: Introductionmentioning

confidence: 99%

“…Since the introduction of DPFs in the early 1980s, a large body of numerical investigations have been carried out to study transport and catalytic reaction phenomena, gas flow and back pressure, soot filtration, and thermal stresses at three different length scales inside a DPF: the porous wall, the filter channel, and the entire DPF volume. [4][5][6] Thorough and comprehensive reviews of the various numerical models, their development over the years, and their validation with experiments can be found in the recent literature. [7,8] For studying fluid flow through the porous wall of a DPF, researchers have either used structural data obtained from a porous medium using X-ray tomography [9][10][11][12] or applied reconstruction algorithms to recreate virtual porous walls from statistical descriptors of the porous medium, following the works of Torquato et al [13][14][15][16] and Kikkinides and Burganos.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of the impact of thermophoresis on the capture efficiency of diesel particulate filters

et al. 2016

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The present study investigates the impact of thermophoresis on soot capture in the clean cordierite porous wall of a diesel particulate filter (DPF). A three-step numerical model was developed, consisting of: (1) numerically reconstructing a representative volume of the cordierite porous wall, (2) computing gas flow through the porous wall using the lattice Boltzmann method, and (3) predicting of the DPF capture efficiency based on the time-dependent solution of a modified Langevin equation that takes thermophoresis into account. The validity of the approach was verified by carefully comparing the permeability predictions of a reconstructed cordierite porous wall to data from the literature. The impact of the magnitude and orientation of the thermophoretic force on the capture of soot particles of various sizes under different flow conditions was investigated. The thermophoretic force applied in or against the flow direction significantly affected the particle capture for the highest particle sizes and flow velocity investigated. Our results suggested that thermophoresis can potentially affect soot deposition uniformity in DPFs. Since the thermophoretic force mainly impacted soot capture efficiency in the presence of particle and flow inertia, a dimensionless criterion defined as the product of Stokes and Reynolds numbers is proposed to predict the onset of what can be called thermophoresis-enhanced inertial impaction. While similar results have been reported by others using simple flow geometries, this is the first time, to our knowledge, that this phenomenon is reported for a complex cordierite porous wall.

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Section: Methodsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of the impact of thermophoresis on the capture efficiency of diesel particulate filters

et al. 2016

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“…This flow rate was selected so that the resulting air velocity of 1.5 m/s through the ESBEC would be within the range of air velocities in actual conventional diesel particulate filters. The latter is estimated based on a typical range of DPF flow rates (11–680 m 3 /hour) and diameters (0.12–0.27 m) (Dou, 2012; Zhong et al, 2012). …”

Section: Methodsmentioning

confidence: 99%

Design and development of an Electrostatic Screen Battery for Emission Control (ESBEC)

Han

Mainelis

2017

Journal of Aerosol Science

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Current diesel particulate filters (DPFs) can effectively capture the exhaust particles, but they add to engine backpressure and accumulate particles during their operation, which results in the need to regenerate the DPFs by burning off the collected particles periodically. This regeneration results in aerosol emissions, especially in the 10–30 nanometer size range and contributes to ultrafine particle pollution. In this research, we designed and developed a prototype of a novel diesel exhaust control device: the Electrostatic Screen Battery for Emissions Control (ESBEC). The device features high particle collection efficiency without adding to the exhaust backpressure and without the need for thermal regeneration of the collected particles. The ESBEC consists of a series of metal mesh screens coated with a superhydrophobic substance and an integrated carbon fiber ionizer to charge the incoming particles. Multiple pairs of screens (e.g., 5 pairs) are arranged in a battery, in which one screen of each pair is supplied with high voltage, and the other is grounded, producing electrostatic field produced across the screens. The application of a superhydrophobic coating onto the screens allows easy removal of the collected particles using liquid without the need for thermal regeneration. The current prototypes of the device were tested with fluorescent polystyrene latex (PSL) particles of 0.2 and 1.2 μm in size and at 25 and 105 L/min sampling flow rates. The average collection efficiency was ~87% for 0.2 μm and ~95% for 1.2 μm PSL particles. In addition, the ESBEC was tested with actual diesel exhaust particles; here its performance was verified by visually inspecting deposition of particles on an after-filter with the device ON and OFF. In the next stages of this work, the ESBEC will be challenged with diesel exhaust at different mass concentrations and for different collection time periods.

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“…It has been widely reported that soot loading with a diesel engine has two distinct stages, the initial stage with a fast, non-linear increase in P and the subsequent stage with a linear, slow increase in P [6,16,17]. On a clean filter, soot particles are collected first within the filter walls, and this process is also call deep-bed filtration.…”

Section: No Oxidation On Csf For Passive Filter Regenerationmentioning

confidence: 98%

NO oxidation on catalyzed soot filters

Weinstein

Roth

2015

Catalysis Today

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Measurement and Prediction of Filtration Efficiency Evolution of Soot Loaded Diesel Particulate Filters

Cited by 27 publications

References 18 publications

Numerical investigation of the impact of thermophoresis on the capture efficiency of diesel particulate filters

Numerical investigation of the impact of thermophoresis on the capture efficiency of diesel particulate filters

Design and development of an Electrostatic Screen Battery for Emission Control (ESBEC)

NO oxidation on catalyzed soot filters

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