Approximate pressure drop and filtration efficiency expressions for semi‐open wall‐flow channels

Haralampous, O. A.; Kontzias, Theodore

doi:10.1002/cjce.21982

Cited by 16 publications

(12 citation statements)

References 14 publications

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“…Figure 12b indicates that less fluid crosses the permeable walls relative to the intact filter, which explains the lower flow rates achieved along the outlet channels, as well as the weaker fluid jets coming out from the unplugged inlet channels. Similar Q w profiles have been obtained previously by utilizing 1D models [24][25][26], while there are no results from 3D CFD studies. The present work provides further insight into the 3D features of the fluid flow in defective filter channels without rear plugs, which can potentially lead to non-uniform particle deposition.…”

Section: Flow Ratessupporting

confidence: 83%

“…For example, Samaras [21] and Finch et al [22] showed that monitoring of the back-pressure in failed PFs, in which the rear plugs were removed artificially, is not adequate for on-board diagnostic purpose. There are also some numerical works utilizing 1D models for flawed PFs without rear plugs [23][24][25][26]. The above-mentioned studies rely on the initial work of Bisset [1] and incorporate proper model adjustments to account for the missing plugs.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study of Flow and Particle Deposition in Wall-Flow Filters with Intact or Damaged Exit

Tzorbatzoglou

Μαστρόκαλος

Haralampous

2019

Fluids

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We examine the time-dependent three-dimensional gas-particle flow in an intact wall-flow filter consisting of channels alternatively plugged at each end and a partially damaged filter in which the rear plugs are removed. Our focus is placed on highlighting the differences in the flow pattern and the deposition process between the two geometries. The Navier–Stokes equations are solved for the fluid flow coupled with a Brinkman/Forchheimmer model in order to simulate the flow in the porous walls and plugs. Discrete particle simulation is utilized to determine the nanoparticle trajectories. Using this scheme, we are able to characterize the main features of the flow fields developing in the intact and damaged filters with respect to the Reynolds number and identify those affecting the transport and deposition of particles that have three representative response times. We present fluid velocity iso-contours, which describe the flow regimes inside the channels, as well as in regions upstream and downstream of them. We provide evidence of local recirculating bubbles at the entrance of the channels and after their exit, whereas back-flow occurs in front of the rear plugs of the intact channels. We show that the flow leaves the channels as strong jets that may break up for certain flow parameters, leading to turbulence with features that depend on the presence of the rear plugs. The removal of the rear plugs affects the flow distribution, which, in turn influences the flow rates along the channels and through the walls. We describe the particle trajectories and the topology of deposited particles and show that particles follow closely the streamlines, which may cross the surface of permeable walls for both flow configurations. The distribution of deposited particles resembles the spatial variation of the through-wall flow rate, exhibiting two peak values at both ends of the intact filter channel, and one local maximum near the entrance of the damaged filter channel that is diminished at the exit. We also investigate in detail the particle deposition on the frontal face and indicate that particle accumulation at the edges of the entrance is favored for particles with low response times in flows with high fluid mass rates for both intact and damaged filters. Finally, we examine the filtration efficiency for the defective channels without rear plugs and show that fewer particles are captured as the Reynolds number is increased. A smaller reduction of the filtration efficiency is also predicted with increasing particle size.

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Section: Flow Ratessupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Numerical Study of Flow and Particle Deposition in Wall-Flow Filters with Intact or Damaged Exit

Tzorbatzoglou

Μαστρόκαλος

Haralampous

2019

Fluids

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“…The reason for this behavior is that the model accounts for the soot loading of the DPF and the effect of exhaust flow. A few publications are focusing on the filtration efficiency of unplugged DPFs [40,41], but there is no available data for transient operation. Therefore, it is not possible to compare or validate the results of this study.…”

Section: Resultsmentioning

confidence: 99%

Uncertainties in Model-Based Diesel Particulate Filter Diagnostics Using a Soot Sensor

Kontses

Geivanidis

Fragkiadoulakis

et al. 2019

Sensors

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Monitoring the filtration efficiency of the diesel particulate filter (DPF), is a legislative requirement for minimizing particulate matter (PM) emissions from diesel engines of passenger cars and heavy-duty vehicles. To reach this target, on-board diagnostics (OBD) in real-time operation are required. Such systems in passenger cars are often utilizing a soot sensor, models for PM emissions simulation and algorithms for diagnosis. Their performance is associated with a series of challenges related to the accuracy and effectiveness of involved models, algorithms and hardware. This paper analyzes the main influencing factors and their impact on the effectiveness of the OBD system. The followed method comprised an error propagation analysis to quantify the error of detection during a New European Driving Cycle (NEDC). The results of the study regarding the performance of the OBD model showed that the total error of diagnosis is ±28%. This performance can be improved by increasing the sensor accuracy and the soot model, which can make the model appropriate for even tighter legislation limits and other approaches such as on-board monitoring (OBM).

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“…To investigate the characteristics of pressure drop and heat regeneration, researchers established a mathematical model of ash deposition in the wall‐flow diesel particulate filter, which was validated by an accelerated aging bench test . In addition, the wall‐flow filter of DPF can suffer damage due to regeneration, so Haralampous and Kontzias proposed approximate expressions for estimating pressure drop and filtration efficiency of semi‐open wall‐flow channels, and estimated the effects of failure on filtration and pressure drop performance by establishing a simulation model for a partially‐failed DPF . From these studies, no research has been conducted on the failure recognition of DPFs, though ash deposition has been preliminarily investigated.…”

Section: Introductionmentioning

confidence: 99%

“…[9][10][11][12] In addition, the wall-flow filter of DPF can suffer damage due to regeneration, so Haralampous and Kontzias proposed approximate expressions for estimating pressure drop and filtration efficiency of semi-open wall-flow channels, and estimated the effects of failure on filtration and pressure drop performance by establishing a simulation model for a partially-failed DPF. [13] From these studies, no research has been conducted on the failure recognition of DPFs, though ash deposition has been preliminarily investigated.…”

Section: Introductionmentioning

confidence: 99%

Failure recognition of the diesel particulate filter based on catastrophe theory

et al. 2016

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In order to effectively recognize the failure behaviour of the diesel particulate filter (DPF), a failure cusp catastrophe model of a porous medium filter in DPF was established using catastrophe theory and diffeomorphism transformation based on the flow resistance model of a porous medium filter with ash deposition. Then, critical points and singular points of the failure cusp catastrophe model were solved and the discriminant of the DPF failure cusp catastrophic model was obtained, which was used to recognize the failure behaviour of the DPF. Finally, failure or critical state details of DPF were acquired via calculation examples, and recognition results of the DPF failure behaviour were verified on the engine bench test. Recognition results of the failure state are consistent with the experimental ones, which confirms the validity of failure recognition based on the failure cusp catastrophe model of DPF, and provides a theoretical basis and reference for research on the failure prediction and diagnosis, as well as the anti-failure, of DPF.Keywords: catastrophe theory, diesel particulate filter, ash deposition, failure, recognition INTRODUCTION D iesel particulate filters (DPF) whose core component is a porous medium filter have been shown to significantly reduce particulate matter (PM) emissions from diesel engines. Further application of diesel particulate filters in automobiles is restricted due to the short life of the porous medium filter. Therefore, how to improve its durability and service life has become an urgent problem. To address this, the failure mechanism of the porous medium filter of DPF requires in-depth study.A key factor responsible for the failure of porous medium filters is pore blockage, which directly results from ash deposition in the channels of the filter. In the past 30 years, most studies have concentrated on the filter structure, capture performance, flow field characteristics, motion and deposition laws of particles and ashes, regeneration characteristics, and blockage of filter channels, [1,2] but research on diesel particulate filter failure is rare. Researchers have carried out theoretical and experimental studies on the ash deposition and pore clogging of porous medium filters, and have optimized their structure in order to extend their service life. Among experimental studies, a vehicle experimental study on the road loading a DPF found that ash comprises > 80 % of the sediment inside the filter.[3] The ash deposition process of DPF on heavy-duty diesel vehicles, physical and chemical properties of ash particles in channels of the porous medium filter, properties of the ash layer, and its effects on the capture performance and the regeneration characteristics of DPF were experimentally studied. [4][5][6] A rapid assessment method of DPF aging based on ash deposition was established. [7] For theoretical studies, a prediction model of exhaust back pressure in the DPF was established by Heibel and Bhargava based on the ash deposition and the regeneration characteristics.[8] To in...

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Approximate pressure drop and filtration efficiency expressions for semi‐open wall‐flow channels

Cited by 16 publications

References 14 publications

Numerical Study of Flow and Particle Deposition in Wall-Flow Filters with Intact or Damaged Exit

Numerical Study of Flow and Particle Deposition in Wall-Flow Filters with Intact or Damaged Exit

Uncertainties in Model-Based Diesel Particulate Filter Diagnostics Using a Soot Sensor

Failure recognition of the diesel particulate filter based on catastrophe theory

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