Effect of Particle Size Distribution on the Deep-Bed Capture Efficiency of an Exhaust Particulate Filter

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Sandeep Viswanathan ◽  
David Rothamer ◽  
Stephen Sakai ◽  
Mitchell Hageman ◽  
David Foster ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Flow Area ◽  
Wall Area ◽  
Filter Loading ◽  
Particle Sizer ◽  
The Impact

The exhaust filtration analysis system (EFA) developed at the University of Wisconsin–Madison was used to perform microscale filtration experiments on cordierite filter samples using particulate matter (PM) generated by a spark ignition direct injection (SIDI) engine fueled with gasoline. A scanning mobility particle sizer (SMPS) was used to characterize running conditions with four distinct particle size distributions (PSDs). The distributions selected differed in the relative number of accumulation versus nucleation mode particles. The SMPS and an engine exhaust particle sizer (EEPS) were used to simultaneously measure the PSD downstream of the EFA and the real-time particulate emissions from the SIDI engine to determine the evolution of filtration efficiency (FE) during filter loading. Cordierite filter samples with properties representative of diesel particulate filters (DPFs) were loaded with PM from the different engine operating conditions. The results were compared to understand the impact of PSD on filtration performance as well as the role of accumulation mode particles on the diffusion capture of PM. The most penetrating particle size (MPPS) was observed to decrease as a result of particle deposition within the filter substrate. In the absence of a soot cake, the penetration of particles smaller than 70 nm was seen to gradually increase with time, potentially due to increased velocities in the filter as flow area reduces during filter loading, or due to decreasing wall area for capture of particles by diffusion. Particle re-entrainment was not observed for any of the operating conditions.

Effect of Particle Size Distribution on the Deep-Bed Capture Efficiency of an Exhaust Particulate Filter

2014 ◽  
Author(s):  
Sandeep Viswanathan ◽  
Stephen S. Sakai ◽  
Mitchell Hageman ◽  
David E. Foster ◽  
Todd Fansler ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Deposition ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Filter Loading ◽  
Particle Sizer ◽  
The Impact

The exhaust filtration analysis system (EFA) developed at the University of Wisconsin – Madison was used to perform micro-scale filtration experiments on cordierite filter samples using particulate matter (PM) generated by a spark-ignition direct injection (SIDI) engine fueled with gasoline. A scanning mobility particle sizer (SMPS) was used to characterize running conditions with four distinct particle size distributions (PSDs). The distributions selected differed in the relative number of accumulation versus nucleation mode particles. The SMPS and an engine exhaust particle sizer (EEPS) were used to simultaneously measure the PSD downstream of the EFA and the real-time particulate emissions from the SIDI engine to determine the evolution of filtration efficiency during filter loading. Cordierite filter samples with properties representative of diesel particulate filters (DPFs) were loaded with PM from the different engine operating conditions. The results were compared to understand the impact of particle size distribution on filtration performance as well as the role of accumulation mode particles on the diffusion capture of PM. The most penetrating particle size (MPPS) was observed to decrease as a result of particle deposition within the filter substrate. In the absence of a soot cake, the penetration of particles smaller than 70 nm was seen to gradually increase with time, potentially due to increased velocities in the filter as flow area reduces during filter loading, or due to decreasing wall area for capture of particles by diffusion. Particle re-entrainment was not observed for any of the operating conditions.

Uncertainty Analysis of Inflow Conditions on an HPT Gas Turbine Nozzle: Effect on Particle Deposition

2020 ◽  
Author(s):  
R. Friso ◽  
N. Casari ◽  
M. Pinelli ◽  
A. Suman ◽  
F. Montomoli
Keyword(s):  
Gas Turbine ◽  
Energy Efficient ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Operating Conditions ◽  
Wide Range ◽  
And Performance ◽  
Gas Turbine Nozzle ◽  
The Impact ◽  
Inflow Conditions

Abstract Gas turbines (GT) are often forced to operate in harsh environmental conditions. Therefore, the presence of particles in their flow-path is expected. With this regard, deposition is a problem that severely affects gas turbine operation. Components’ lifetime and performance can dramatically vary as a consequence of this phenomenon. Unfortunately, the operating conditions of the machine can vary in a wide range, and they cannot be treated as deterministic. Their stochastic variations greatly affect the forecasting of life and performance of the components. In this work, the main parameters considered affected by the uncertainty are the circumferential hot core location and the turbulence level at the inlet of the domain. A stochastic analysis is used to predict the degradation of a high-pressure-turbine (HPT) nozzle due to particulate ingestion. The GT’s component analyzed as a reference is the HPT nozzle of the Energy-Efficient Engine (E3). The uncertainty quantification technique used is the probabilistic collocation method (PCM). This work shows the impact of the operating conditions uncertainties on the performance and lifetime reduction due to deposition. Sobol indices are used to identify the most important parameter and its contribution to life. The present analysis enables to build confidence intervals on the deposit profile and on the residual creep-life of the vane.

scholarly journals A mechanistic framework for a priori pharmacokinetic predictions of orally inhaled drugs

2020 ◽  
Vol 16 (12) ◽  
pp. e1008466
Author(s):  
Niklas Hartung ◽  
Jens Markus Borghardt
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Mechanistic Model ◽  
A Priori ◽  
Systemic Exposure ◽  
Drug Dissolution ◽  
Mathematical Framework ◽  
Inhaled Drugs ◽  
Optimal Drug ◽  
The Impact

The fate of orally inhaled drugs is determined by pulmonary pharmacokinetic processes such as particle deposition, pulmonary drug dissolution, and mucociliary clearance. Even though each single process has been systematically investigated, a quantitative understanding on the interaction of processes remains limited and therefore identifying optimal drug and formulation characteristics for orally inhaled drugs is still challenging. To investigate this complex interplay, the pulmonary processes can be integrated into mathematical models. However, existing modeling attempts considerably simplify these processes or are not systematically evaluated against (clinical) data. In this work, we developed a mathematical framework based on physiologically-structured population equations to integrate all relevant pulmonary processes mechanistically. A tailored numerical resolution strategy was chosen and the mechanistic model was evaluated systematically against data from different clinical studies. Without adapting the mechanistic model or estimating kinetic parameters based on individual study data, the developed model was able to predict simultaneously (i) lung retention profiles of inhaled insoluble particles, (ii) particle size-dependent pharmacokinetics of inhaled monodisperse particles, (iii) pharmacokinetic differences between inhaled fluticasone propionate and budesonide, as well as (iv) pharmacokinetic differences between healthy volunteers and asthmatic patients. Finally, to identify the most impactful optimization criteria for orally inhaled drugs, the developed mechanistic model was applied to investigate the impact of input parameters on both the pulmonary and systemic exposure. Interestingly, the solubility of the inhaled drug did not have any relevant impact on the local and systemic pharmacokinetics. Instead, the pulmonary dissolution rate, the particle size, the tissue affinity, and the systemic clearance were the most impactful potential optimization parameters. In the future, the developed prediction framework should be considered a powerful tool for identifying optimal drug and formulation characteristics.

Tailor Made Biofuels: Effect of Fuel Properties on the Soot Microstructure and Consequences on Particle Filter Regeneration

2013 ◽  
Author(s):  
Om Parkash Bhardwaj ◽  
Bernhard Lüers ◽  
Andreas F. Kolbeck ◽  
Thomas Koerfer ◽  
Florian Kremer ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Soot Oxidation ◽  
Operating Conditions ◽  
Fuel Properties ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Soot Emission ◽  
Diesel Particulate ◽  
The Future ◽  
Dpf Regeneration

In recent years a lot of effort has been made to understand the phenomena of Diesel Particulate Filter (DPF) regeneration processes but less attention has been paid to understand the influence of fuel properties on soot reactivity and its consequence on the DPF regeneration behavior. Within the Cluster of Excellence “Tailor-Made Fuels from Biomass (TMFB)” at RWTH Aachen University, the Institute for Combustion Engines carried out a detailed investigation program to explore the potential of future biofuel candidates for optimized combustion systems. These new biofuels are being developed to realize partially homogeneous low-temperature combustion, in order to reduce the emission and fuel consumption to meet future requirements. The chemical structure of these new fuels may impact the thermal decomposition chemistry and hence the in-cylinder particulate formation conditions. This work fundamentally focusses the influence of fuel properties on particulate matter reactivity and, thereby, the regeneration behavior of the diesel particulate filters (DPF). The experiments for particulate measurements and analysis were conducted, under constant engine operating conditions, on a EURO 6 compliant High Efficiency Combustion System (HECS) fuelled with petroleum based diesel fuel as baseline and today’s biofuels like FAME and Fischer Tropsch fuels as well as potential biomass derived fuel candidates being researched in TMFB. Several different methods were used for analysis of mass, composition, structure and spectroscopic parameters of the soot. The graphitic microstructure visible with high resolution transmission electron microscopy (HRTEM) was compared to the results of X-Ray diffraction (XRD), optical light absorption measurement and elementary analysis of samples. The results indicate that combustion with increasing fuel oxygenation produces decreasing engine-out particulate emissions. The ranking of activation energies of soot oxidation analysis from LGB experiments correspond well with the ranking of the soot physico-chemical properties. In comparison to petroleum based diesel fuel, the reduction of engine out soot emission by a factor of five with the use of the future biomass derived fuel candidate was accompanied by ten times reduction of the soot volume based absorption coefficient and two times reduction of carbon to hydrogen ratio. As a result of it, the activation energy of soot oxidation in DPF reduced by ∼ 10 KJ/mol. The reduced engine out soot emission and increased reactivity of the soot from the future biomass derived fuel candidate could cause a significant reduction of thermal DPF regenerations.

Particulate Morphology Characterization of Butanol–Gasoline Blend Fueled Spark-Ignition Direct Injection Engine

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Nikhil Sharma ◽  
Avinash Kumar Agarwal
Keyword(s):  
Size Distribution ◽  
Primary Particle ◽  
Direct Injection ◽  
Operating Conditions ◽  
Physical Characterization ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Potential Candidate ◽  
Gdi Engine

Abstract Butanol is an oxygenated renewable fuel and therefore is a potential candidate to be blended with gasoline to reduce particulate emissions. In this experimental investigation, particle number-size (PN-size) distribution and morphology (physical characterization) of soot emitted by the butanol–gasoline blend in a gasoline direct injection (GDI) engine have been investigated. The effect of engine load and fuel injection pressure (FIP) on particulates was investigated for two test fuels: gasoline and Bu15 (85%, v/v, gasoline blended with 15%, v/v, butanol) in a 0.5 L single-cylinder GDI engine using an engine exhaust particulate sizer (EEPS) and a partial flow dilution tunnel for collecting particulate samples on a filter paper. The physical characterization of particulates included primary particle size (Dp) and particle agglomerate characterization parameters such as agglomerate length (L), agglomerate width (W), skeletal length (Lsk) and skeletal width (Wsk), which were determined using a transmission electron microscope (TEM) and corresponding image analyses. PN-size distribution was relatively lower for Bu15, which decreased with increasing FIP. Regardless of the GDI engine operating condition, classical sphere and chain-like agglomerates having nearly similar nano-scale morphology were detected. The primary particle diameter changed with varying engine operating conditions. A comparative analysis of soot originating from Bu15 and gasoline was presented, which may be useful for gasoline particulate filter (GPF) design and to understand the regeneration of GPFs in practical engine applications.

scholarly journals Development of a Novel Gasoline Particulate Filter Loading Method Using a Burner Bench

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4914
Author(s):  
Frank Dorscheidt ◽  
Stefan Pischinger ◽  
Johannes Claßen ◽  
Stefan Sterlepper ◽  
Sascha Krysmon ◽  
...  
Keyword(s):  
Test Bench ◽  
Gasoline Engine ◽  
Geometric Mean ◽  
Calibration Procedure ◽  
Pollutant Emissions ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Exhaust Gas ◽  
Gasoline Particulate Filter ◽  
Filter Loading

In view of the deliberations on new Euro 7 emission standards to be introduced by 2025, original equipment manufacturers (OEMs) are already hard at work to further minimise the pollutant emissions of their vehicles. A particular challenge in this context will be compliance with new particulate number (PN) limits. It is expected that these will be tightened significantly, especially by including particulates down to 10 nm. This will lead to a substantially increased effort in the calibration of gasoline particulate filter (GPF) control systems. Therefore, it is of great interest to implement advanced methods that enable shortened and at the same time more accurate GPF calibration techniques. In this context, this study presents an innovative GPF calibration procedure that can enable a uniquely efficient development process. In doing so, some calibration work packages involving GPF soot loading and regeneration are transferred to a modern burner test bench. This approach can minimise the costly and time-consuming use of engine test benches for GPF calibration tasks. Accurate characterisation of the particulate emissions produced after a cold start by the target engine in terms of size distribution, morphology, and the following exhaust gas backpressure and burn-off rates of the soot inside the GPF provides the basis for a precise reproduction and validation process on the burner test bench. The burner test bench presented enables the generation of particulates with a geometric mean diameter (GMD) of 35 nm, exactly as they were measured in the exhaust gas of the engine. The elemental composition of the burner particulates also shows strong similarities to the particulates produced by the gasoline engine, which is further confirmed by matching burn-off rates. Furthermore, the exhaust backpressure behaviour can accurately be reproduced over the entire loading range of the GPF. By shifting GPF-related calibration tasks to the burner test bench, total filter loading times can be reduced by up to 93%.

scholarly journals Particulates mass and number emission from hybrid vehicle in RDE test

2019 ◽  
Vol 24 (6) ◽  
pp. 286-290
Author(s):  
Natalia Szymlet ◽  
Barbara Sokolnicka ◽  
Maciej Sieldecki ◽  
Piotr Lijewski ◽  
Mateusz Nowak
Keyword(s):  
Hybrid Vehicle ◽  
Operating Conditions ◽  
Exhaust Emission ◽  
Particulate Emissions ◽  
Vehicle Exhaust ◽  
Engine Exhaust ◽  
Limit Values ◽  
Emission Limit ◽  
And Performance ◽  
Particle Sizer

The subject of this article is the analysis of the particle number and mass road emission from a hybrid vehicle in real operating conditions. Additionally, the operating conditions of the tested vehicle and engine were also analyzed. To this end, particulate emissions and performance tests were carried out from a light hybrid vehicle, equipped with a 77 kW engine with a displacement of 1.58 dm3. The tests were conducted in real traffic conditions, following the standard RDE (Real Driving Emission) procedure. The test was performed within the Poznań agglomeration, the route included roads with different maxi-mum speed limits. The research involved the use of mobile measuring equipment, belonging to the PEMS (Portable Emissions Measurement System) group, which included equipment such as: SEMTECH DS, AVL MSS (Micro Soot Sensor) and EEPS 3090 (Engine Exhaust Particle Sizer). The results obtained have been referred to the vehicle exhaust emission limit values in accordance with the Euro 6 norm.

scholarly journals Aerosol dynamics within and above forest in relation to turbulent transport and dry deposition

2015 ◽  
Vol 15 (14) ◽  
pp. 19367-19403 ◽  
Author(s):  
Ü. Rannik ◽  
L. Zhou ◽  
P. Zhou ◽  
R. Gierens ◽  
I. Mammarella ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Time Scales ◽  
Atmospheric Chemistry ◽  
Dry Deposition ◽  
Particle Deposition ◽  
Vertical Transport ◽  
Forest Site ◽  
Aerosol Dynamics ◽  
The Impact

Abstract. One dimensional atmospheric boundary layer (ABL) model coupled with detailed atmospheric chemistry and aerosol dynamical model, the model SOSAA, was used to predict the ABL and detailed aerosol population (characterized by the number size distribution) time evolution. The model was applied over a period of ten days in May 2013 for a pine forest site in southern Finland. The period was characterized by frequent new particle formation events and simultaneous intensive aerosol transformation. Throughout this study we refer to nucleation, condensational growth and coagulation as aerosol dynamical processes, i.e. the processes that govern the particle size distribution evolution. The aim of the study was to analyze and quantify the role of aerosol and ABL dynamics in vertical transport of aerosols. It was of particular interest to what extent the fluxes above canopy deviate due to above mentioned processes from the particle dry deposition on the canopy foliage. The model simulations revealed that the particle concentration change due to aerosol dynamics can frequently exceed the effect of particle deposition even an order of magnitude or more. The impact is however strongly dependent on particle size and time. In spite of the fact that the time scale of turbulent transfer inside canopy is much smaller than the time scales of aerosol dynamics and dry deposition, letting to assume well mixed properties of air, the fluxes at the canopy top frequently deviate from deposition inside forest. This is due to transformation of aerosol concentration throughout the ABL and resulting complicated pattern of vertical transport. Therefore we argue that the comparison of time scales of aerosol dynamics and deposition defined for the processes below the flux measurement level do not unambiguously describe the importance of aerosol dynamics for vertical transport within canopy. We conclude that under dynamical conditions the micrometeorological particle flux measurements such as performed by the eddy covariance technique do not generally represent the dry deposition. The deviation can be systematic for certain size ranges so that the conclusion applies also to time averaged particle fluxes.

scholarly journals Particle Entrainment and Deposition Scenario in Sublayer Region of Variable Area Conduit

2020 ◽  
Vol 162 ◽  
pp. 03006
Author(s):  
Esam Jassim
Keyword(s):  
Particle Size ◽  
Flow Velocity ◽  
Particle Deposition ◽  
Particle Energy ◽  
Adhesion Energy ◽  
Low Flow ◽  
Threshold Velocity ◽  
Fate Decision ◽  
The Impact ◽  
Aggregation Phenomena

The study presents the particle deposition and aggregation phenomena by introducing new parameter called Particle Deposition Number PDN, defined as the ratio of the particle instantaneous velocity to its capturing value. The particle capture or rebound fate will decide from knowing such number. The study employed new scheme of particle deposition in the sublayer region which includes balancing of four forces. Moreover, the bouncing model is also considered for particle fate decision. The study examines the variation of particle velocity at varying area tube and the critical velocity in which particle will tend to stick if its velocity is lower than the threshold limit. The results show that threshold velocity is exponentially decreased with the increment in the particle size. Capturing of particles is shown to be enhanced as the conduit converges due to increasing in the PDN. The analysis of the deposition also investigates the impact of the particle size on the PDN. At low flow velocity, the NDP has V-shaped trend as particle size increases. However, veering toward constant PDN value has occurred as the flow velocity augmented. Finally, small sized particles experience rebound due to the prevailing of the particle impact energy over the adhesion energy before impacting with the surface. The dissipation in the particle energy during impaction causes large sized particle to loose greater amount of energy compare to small sized one, resulting in domination of the adhesion part, which leads to deposition on the surface.

scholarly journals Estimation of aerosol particle number distribution with Kalman Filtering – Part 2: Simultaneous use of DMPS, APS and nephelometer measurements

2012 ◽  
Vol 12 (24) ◽  
pp. 11781-11793 ◽  
Author(s):  
T. Viskari ◽  
E. Asmi ◽  
A. Virkkula ◽  
P. Kolmonen ◽  
T. Petäjä ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Kalman Filtering ◽  
Particle Density ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
State Estimate ◽  
Different Types ◽  
Particle Sizer ◽  
The Impact

Abstract. Extended Kalman Filter (EKF) is used to estimate particle size distributions from observations. The focus here is on the practical application of EKF to simultaneously merge information from different types of experimental instruments. Every 10 min, the prior state estimate is updated with size-segregating measurements from Differential Mobility Particle Sizer (DMPS) and Aerodynamic Particle Sizer (APS) as well as integrating measurements from a nephelometer. Error covariances are approximate in our EKF implementation. The observation operator assumes a constant particle density and refractive index. The state estimates are compared to particle size distributions that are a composite of DMPS and APS measurements. The impact of each instrument on the size distribution estimate is studied. Kalman Filtering of DMPS and APS yielded a temporally consistent state estimate. This state estimate is continuous over the overlapping size range of DMPS and APS. Inclusion of the integrating measurements further reduces the effect of measurement noise. Even with the present approximations, EKF is shown to be a very promising method to estimate particle size distribution with observations from different types of instruments.

Sign in / Sign up

Export Citation Format

Share Document