scholarly journals Experimental Study on the Influence of DPF Micropore Structure and Particle Property on Its Filtration Process

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Zhongwei Meng ◽  
Jia Fang ◽  
Yunfei Pu ◽  
Yan Yan ◽  
Yi Wu ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Pore Structure ◽  
Layer Thickness ◽  
Filtration Velocity ◽  
Cake Filtration ◽  
Diesel Particle Filter ◽  
Deep Bed Filtration ◽  
Particle Layer ◽  
Particle Property ◽  
Filtration Stage

A single layer filtration system was developed to investigate the filtration and regeneration performance of diesel particle filter (DPF). The particle layer thickness was directly measured online to analyze the different filtration stages. The influence of particle property on particle layer stage performance was also investigated. The results indicate that the filtration velocity can greatly affect the deep bed filtration stage, and the deposited particle layer can be compressed even in very low filtration velocity and higher filtration velocity trends to form denser particle layer. Optimizing the pore structure can effectively shorten the deep bed filtration stage and reduce the pressure drop eventually. An empirical function was proposed to relate the pore structure and the initial increment rate of pressure drop, which presented that reducing the pore size distribution range (3σ) can result in low DPF filtration pressure drop. The filtration stage could be further divided into four stages, and the value of particle layer thickness ranging within 15~20 μm has been found to be critical number for the shift from the transient stage to the cake filtration stage. Particle with large primary diameter and BET surface was beneficial to form loose particle layer.

Bingham Fluid Flow in the Entrance Region of a Pipe

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Basma Baioumy ◽  
Rachid Chebbi ◽  
Nabil Abdel Jabbar
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Bingham Fluid ◽  
Entrance Region ◽  
Integral Model ◽  
Fully Developed Flow

Abstract Laminar Bingham fluid flow in the entrance region of a circular pipe is investigated using a momentum integral model. The fully developed flow is uniform in the core region, while the velocity changes in the annular part of the cross section of the pipe. The inlet-filled region concept is adopted. In the inlet region, the boundary layer thickness increases until the size of the plug flow area reaches the fully developed flow size. The model converges to the fully developed solution in the filled region. The model provides the velocity, pressure drop, and skin friction coefficient profiles. The pressure drop results are in good agreement with published experimental data. The flow results asymptotically converge to the fully developed values. In addition, the results are consistent with published Newtonian fluid flow experimental data and theoretical results for the boundary layer thickness, pressure drop, and centerline velocity for small values of the Bingham number.

scholarly journals Experimental and numerical study of wall layer development in a tribocharged fluidized bed

2018 ◽  
Vol 849 ◽  
pp. 860-884 ◽  
Author(s):  
Petteri Sippola ◽  
Jari Kolehmainen ◽  
Ali Ozel ◽  
Xiaoyu Liu ◽  
Pentti Saarenrinne ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Numerical Study ◽  
Single Layer ◽  
Wall Layer ◽  
Small Scale ◽  
Average Charge ◽  
Particle Layer ◽  
Column Wall ◽  
Triboelectric Charging

The effects of triboelectricity in a small-scale fluidized bed of polyethylene particles were investigated by imaging the particle layer in the vicinity of the column wall and by measuring the pressure drop across the bed. The average charge on the particles was altered by changing the relative humidity of the gas. A triboelectric charging model coupled with a computational fluid dynamics–discrete element method (CFD-DEM) model was utilized to simulate gas–particle flow in the bed. The electrostatic forces were evaluated based on a particle–particle particle–mesh method, accounting for the surface charge on the insulating walls. It was found that simulations with fixed and uniform charge distribution among the particles capture remarkably well both the agglomeration of the particles on the wall and the associated decrease in the pressure drop across the bed. With a dynamic tribocharging model, the charging rate had to be accelerated to render the computations affordable. Such simulations with an artificial acceleration significantly over-predict charge segregation and the wall becomes rapidly sheeted with a single layer of strongly charged particles.

Numerical Modeling of Multidirectional Flow and Heat Transfer in Graphitic Foams

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
S. A. Mohsen Karimian ◽  
Anthony G. Straatman
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Pore Structure ◽  
Linear Models ◽  
A Priori ◽  
Experimental Results ◽  
Transfer Model ◽  
Thermal Dispersion ◽  
Wide Range ◽  
Graphitic Foam

To investigate the feasibility of the use of foams with an interconnected spherical pore structure in heat transfer applications, models for heat transfer and pressure drop for this type of porous materials are developed. Numerical simulations are carried out for laminar multidirectional thermofluid flow in an idealized pore geometry of foams with a wide range of geometry parameters. Semiheuristic models for pressure drop and heat transfer are developed from the results of simulations. A simplified solid-body drag equation with an extended high inertia term is used to develop the hydraulic model. A heat transfer model with a nonzero asymptotic term for very low Reynolds numbers is also developed. To provide hydraulic and heat transfer models suitable for a wide range of porosity, only a general form of the length-scale as a function of pore structure is defined a priori, where the parameters of the function were determined as part of the modeling process. The proposed ideal models are compared to the available experimental results, and the source of differences between experimental results and the ideal models is recognized and then calibrated for real graphitic foam. The thermal model is used together with volume-averaged energy equations to calculate the thermal dispersion in graphitic foam. The results of the calculations show that the linear models for thermal dispersion available in literature are oversimplified for predicting thermal dispersion in this type of porous material.

scholarly journals Peristaltic transport of a two-layered fluid in a catheterized tube

2012 ◽  
Vol 39 (4) ◽  
pp. 291-311
Author(s):  
Amit Medhavi ◽  
U.K. Singh
Keyword(s):  
Pressure Drop ◽  
Linear Relationship ◽  
Layer Thickness ◽  
Friction Force ◽  
Flow Rate ◽  
Tube Wall ◽  
Flow Characteristics ◽  
Tube Size ◽  
Friction Forces ◽  
Catheter Size

The flow of a two-layered Newtonian fluid induced by peristaltic waves in a catheterized tube has been investigated. The expressions for the flow characteristics- the flow rate, the pressure drop and the friction forces at the tube and catheter wall are derived. It is found that the pressure drop increases with the flow rate but decreases with the increasing peripheral layer thickness and a linear relationship between pressure and flow exists. The pressure drop increases with the catheter size (radius) and assumes a high asymptotic magnitude at the catheter size more that the fifty percent of the tube size. The friction forces at the tube and catheter wall posses characteristics similar to that of the pressure drop with respect to any parameter. However, friction force at catheter wall assumes much smaller magnitude than the corresponding value at the tube wall.

scholarly journals Preliminary study on the performance of biomorphic silicon carbide as substrate for diesel particulate filters

2018 ◽  
Vol 22 (5) ◽  
pp. 2053-2064
Author(s):  
Maria Orihuela ◽  
Aurora Gomez-Martin ◽  
Jose Becerra-Villanueva ◽  
Javier Serrano-Reyes ◽  
Francisco Jimenez-Espadafor ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Pressure Drop ◽  
Space Velocity ◽  
Diesel Particle Filter ◽  
Diesel Particulate ◽  
Pressure Drops ◽  
Diesel Particulate Filters ◽  
Particulate Filters ◽  
Hierarchical Porous ◽  
Porous Microstructure

This paper presents the results of a preliminary experimental study to assess the performance of biomorphic silicon carbide when used for the abatement of soot particles in the exhaust of Diesel engines. Given its optimal thermal and mechanical properties, silicon carbide is one of the most popular substrates in commercial diesel particulate filters. Biomorphic silicon carbide is known for having, be-sides, a hierarchical porous microstructure and the possibility of tailoring that microstructure through the selection of a suitable wood precursor. An experimental rig was designed and built to be integrated within an engine test bench that allowed to characterizing small lab-scale biomorphic silicon carbide filter samples. A particle counter was used to measure the particles distribution before and after the samples, while a differential pressure sensor was used to measure their pressure drop during the soot loading process. The experimental campaign yielded promising results: for the flow rate conditions that the measuring devices imposed (1 litre per minute; space velocity = 42,000 L/h), the samples showed initial efficiencies above 80%, pressure drops below 20 mbar, and a low increase in the pressure drop with the soot load which allows to reach almost 100% efficiency with an increase in pressure drop lower than 15%, when the soot load is still less than 0.01 g/L. It shows the potential of this material and the interest for advancing in more complex diesel particle filter designs based on the results of this work.

Thermo-Fluid Optimization of a Solar Porous Absorber With a Variable Pore Structure

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
P. Wang ◽  
J. B. Li ◽  
K. Vafai ◽  
L. Zhao ◽  
L. Zhou
Keyword(s):  
Pressure Drop ◽  
Pore Structure ◽  
Pore Diameter ◽  
Evaluation Criteria ◽  
Poor Performance ◽  
Diameter Distribution ◽  
Maximum Deviation ◽  
Radiation Fields ◽  
Wide Range ◽  
Fluid Optimization

Optimization based on reconstruction of the velocity, temperature, and radiation fields in a porous absorber with continuous linear porosity or pore diameter distribution is carried out in this work. This study analyzes three typical linear pore structure distributions: increasing (“I”), decreasing (“D”), and constant (“C”) types, respectively. In general, the D type porosity (ϕ) layout combined with the I type pore diameter (dp) distribution would be an excellent pore structure layout for a porous absorber. The poor performance range, which should be avoided in the absorber design, is found to be within a wide range of porosity layouts (ϕi = ∼0.7 and ϕo > 0.6) and pore diameter layouts (di = 1.5–2.5 mm), respectively. With a large inlet porosity (ϕi > 0.8), the D type layout with larger porosity gradient (Gp) has a better thermal performance; however, the I type dp layout with a smaller inlet pore diameter (di < 1.5 mm) and a larger pore diameter gradient (Gdp) is recommended when considering the lower pressure drop. Different pore structure layouts (D type or I type) have a significant effect on the pressure drop, even with the same average ϕa and da, the maximum deviation can be up to 70.1%. The comprehensive performance evaluation criteria (PEC) value shows that the D type ϕ layout with a larger ϕa has an excellent thermopressure drop performance, and a part of PEC values for the I type dp layout are greater than unity.

Better understanding of the filtration characteristics in the flexible fibre filter module (3FM)

2007 ◽  
Vol 55 (1-2) ◽  
pp. 77-83 ◽  
Author(s):  
J.J. Lee ◽  
J.H. Im ◽  
R. BenAim ◽  
J.R. Kim ◽  
Y.J. Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Pressure Drop ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Laboratory Scale ◽  
Filtration Velocity ◽  
Operating Parameters ◽  
Particle Retention ◽  
Packing Densities

This study is about the particle retention and filtration characteristics of fibre filter. Four laboratory scale fibre filters with different heights were used in parallel at various packing densities and filtration velocities. Of all of the operating parameters studied, filtration velocity had the most influence. Contrary to general theories, pressure drop increases slightly during the filtration in spite of the continuous retention of particles. This may have occurred because of large porosity of the packing (about 93%). This might be considered an advantage of the filter and something that makes it economic. The higher the filtration velocity, the larger the mass of particles retained in the filter. For filtration velocities of 20 and 40 m/h, particles smaller than 5 μm are retained as proven by the particle size distribution at the inlet and outlet.

Sign in / Sign up

Export Citation Format

Share Document