Study on Soot Mass Fraction and Size Distribution in a Direct Injection Diesel Engine Using Particulate Size Mimic Soot Model

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Fadzli Ibrahim ◽  
Wan Mohd Faizal Wan Mahmood ◽  
Shahrir Abdullah ◽  
Mohd Radzi Abu Mansor
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Mass Fraction ◽  
Size Range ◽  
Particle Size Range ◽  
Soot Particles ◽  
Soot Mass ◽  
Particulate Size ◽  
The Relationship ◽  
Soot Model

Abstract With today's computing technology, research on soot particles using simulation works has become more preferable as a supplementary to the existing experimental methods. The objective of this study is to investigate the effect of different engine load conditions to in-cylinder soot particles formation. This is to clarify the relationship between soot mass fraction (SMF) and size distribution. The first section of the study is conducted by computational analysis using a detailed kinetics soot model, particulate size mimic (PSM), which is based on the concept of the discrete sectional method. The analysis is carried out within closed-cycle combustion environment which is from the inlet valve closing (IVC) to the exhaust valve opening (EVO). The next section is conducted by experimental work deliberately for validation purpose. The total soot mass obtained from the computational work during EVO is comparable to the calculated value by less than 13% error for all of the experimental cases. The soot size distribution measurement indicates that exhaust out particles are dominantly in the dual-mode size range, <10 nm and 11–30 nm. The relationship between the soot mass and size distribution demonstrates that soot mass fraction does not completely rely on soot size distribution as well as particle size range. In most of the cases, particles with the moderate size range (11–60 nm) hold the highest mass fraction during EVO. On the whole, this paper provides significant information that contributes key knowledge to indicate that soot mass fraction is not entirely dependent on soot size distribution as well as particle size range.

scholarly journals Particulate Size of Microalgal Biomass Affects Hydrolysate Properties and Bioethanol Concentration

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Razif Harun ◽  
Michael K. Danquah ◽  
Selvakumar Thiruvenkadam
Keyword(s):  
Particle Size ◽  
Enzymatic Hydrolysis ◽  
Size Range ◽  
Enzyme Hydrolysis ◽  
Particle Size Range ◽  
Microalgal Biomass ◽  
Process Systems ◽  
Particulate Size ◽  
Biomass Particle Size ◽  
Bioethanol Yield

Effective optimization of microalgae-to-bioethanol process systems hinges on an in-depth characterization of key process parameters relevant to the overall bioprocess engineering. One of the such important variables is the biomass particle size distribution and the effects on saccharification levels and bioethanol titres. This study examined the effects of three different microalgal biomass particle size ranges, 35 μm ≤x≤ 90 μm, 125 μm ≤x≤ 180 μm, and 295 μm ≤x≤ 425 μm, on the degree of enzymatic hydrolysis and bioethanol production. Two scenarios were investigated: single enzyme hydrolysis (cellulase) and double enzyme hydrolysis (cellulase and cellobiase). The glucose yield from biomass in the smallest particle size range (35 μm ≤x≤ 90 μm) was the highest, 134.73 mg glucose/g algae, while the yield from biomass in the larger particle size range (295 μm ≤x≤ 425 μm) was 75.45 mg glucose/g algae. A similar trend was observed for bioethanol yield, with the highest yield of 0.47 g EtOH/g glucose obtained from biomass in the smallest particle size range. The results have shown that the microalgal biomass particle size has a significant effect on enzymatic hydrolysis and bioethanol yield.

Reconstructed expression for aerosol extinction coefficient by considering mass extinction efficiency and hygroscopic growth for polydipersed aerosol

2020 ◽  
Author(s):  
Chang Hoon Jung ◽  
JiYi Lee ◽  
Junshik Um ◽  
Yong Pyo Kim
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Growth Factor ◽  
Size Distribution ◽  
Enhancement Factor ◽  
Size Range ◽  
Geometric Mean ◽  
Mie Theory ◽  
Hygroscopic Growth ◽  
Particle Size Range

<p>In this study, simplified analytic type of expression for size dependent MEs (Mass efficiencies) are developed. The entire size was considered assuming lognormal size distribution for sulfate, nitrate and NaCl aerosol species and the MEE of each aerosol chemical composition was estimated by fitting Mie’s calculation. The obtained results are compared with the results from the Mie-theory-based calculations and showed comparable results.</p><p>The mass efficiencies of all aerosol components for each size range are compared with Mie’s results and approximated as a function of geometric mean diameter in the form of a power law formula. Finally, harmonic mean type approximation was used to cover entire particle size range.</p><p>Also, analytic expression of approximated scattering enhancement factor which stands for the effect of hygroscopic growth factor for polydispersed aerosol on aerosol optical properties are obtained.</p><p>Based on aerosol thermodynamic models, mass growth factor can be obtained and their optical properties can be obtained by using Mie theory with different aerosol properties and size distribution. Finally, scattering enhancement factor was approximated fRH for polydispersed aerosol as a function of RH.</p><p>Finally, we also compared the simple forcing efficiency (SFE, W/g) of polydisperse aerosols between the developed simple approach and by the method using the Mie theory. The results show that current obtained approximated methods are comparable with existing numercal calculation based results for polydipersed particle size.</p>

scholarly journals Effect of electronic cigarette (EC) aerosols on particle size distribution in indoor air and in a radon chamber

Nukleonika ◽  
2019 ◽  
Vol 64 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Hyam Nazmy Khalaf ◽  
Mostafa Y. A. Mostafa ◽  
Michael Zhukovsky
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Indoor Air ◽  
Size Range ◽  
Aerosol Particles ◽  
Ultrafine Particle ◽  
Decay Product ◽  
Electronic Cigarette ◽  
Particle Size Range

Abstract Particle size distribution is an important factor governing whether aerosols can be deposited in various respiratory tract regions in humans. Recently, electronic cigarette (EC), as the alternative of tobacco cigarette, has become increasingly popular all over the world. However, emissions from ECs may contribute to both indoor and outdoor air pollution; moreover, comments about their safety remain controversial, and the number of users is increasing rapidly. In this investigation, aerosols were generated from ECs and studied in the indoor air and in a chamber under controlled conditions of radon concentration. The generated aerosols were characterized in terms of particle number concentrations, size, and activity distributions by using aerosol diffusion spectrometer (ADS), diffusion battery, and cascade impactor. The range of ADS assessment was from 10−3 μm to 10 μm. The number concentration of the injected aerosol particles was between 40 000 and 100 000 particles/cm3. The distribution of these particles was the most within the ultrafine particle size range (0–0.2 μm), and the other particle were in the size range from 0.3 μm to 1 μm. The surface area distribution and the mass size distribution are presented and compared with bimodal distribution. In the radon chamber, all distributions were clearly bimodal, as the free radon decay product was approximately 1 nm in diameter, with a fraction of ~0.7 for a clean chamber (without any additional source of aerosols). The attached fraction with the aerosol particles from the ECs had a size not exceeding 1.0 μm.

scholarly journals Size distributions of polycyclic aromatic hydrocarbons in urban atmosphere: sorption mechanism and source contributions to respiratory deposition

2016 ◽  
Vol 16 (5) ◽  
pp. 2971-2983 ◽  
Author(s):  
Yan Lv ◽  
Xiang Li ◽  
Ting Ting Xu ◽  
Tian Tao Cheng ◽  
Xin Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Respiratory System ◽  
Aromatic Hydrocarbons ◽  
Size Range ◽  
Particle Size Range ◽  
Polycyclic Aromatic ◽  
Human Respiratory System

Abstract. In order to better understand the particle size distribution of polycyclic aromatic hydrocarbons (PAHs) and their source contribution to human respiratory system, size-resolved PAHs have been studied in ambient aerosols at a megacity Shanghai site during a 1-year period (2012–2013). The results showed the PAHs had a bimodal distribution with one mode peak in the fine-particle size range (0.4–2.1 µm) and another mode peak in the coarse-particle size range (3.3–9.0 µm). Along with the increase in ring number of PAHs, the intensity of the fine-mode peak increased, while the coarse-mode peak decreased. Plotting of log(PAH / PM) against log(Dp) showed that all slope values were above −1, suggesting that multiple mechanisms (adsorption and absorption) controlled the particle size distribution of PAHs. The total deposition flux of PAHs in the respiratory tract was calculated as being 8.8 ± 2.0 ng h−1. The highest lifetime cancer risk (LCR) was estimated at 1.5  ×  10−6, which exceeded the unit risk of 10−6. The LCR values presented here were mainly influenced by accumulation mode PAHs which came from biomass burning (24 %), coal combustion (25 %), and vehicular emission (27 %). The present study provides us with a mechanistic understanding of the particle size distribution of PAHs and their transport in the human respiratory system, which can help develop better source control strategies.

381. Sampling Efficiencies of Three Personal Aerosol Samplers within and Beyond the Inhalable Particle Size Range

2001 ◽  
Author(s):  
V. Aizenberg ◽  
P. Baron ◽  
K. Choe ◽  
S. Grinshpun ◽  
K. Willeke
Keyword(s):  
Particle Size ◽  
Size Range ◽  
Particle Size Range

scholarly journals Particle Size Distribution Based Occurrence Features of Organic Components in Printing and Dyeing Wastewater Under a Treatment Process

2019 ◽  
Vol 118 ◽  
pp. 04009
Author(s):  
Yuan Li ◽  
Jie Liu ◽  
Yibiao Yu ◽  
Hao Zhu ◽  
Zheng Shen ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Reverse Osmosis ◽  
Treatment Process ◽  
Dyeing Wastewater ◽  
Wastewater Treatment Process ◽  
Printing And Dyeing Wastewater ◽  
Sedimentation Tank ◽  
The Relationship

A more detailed occurrence features of organic matters in the printing and dyeing wastewater, based on its particle size distribution (PSD) and along with a wastewater treatment process, was conducted to provide a support for advanced treatment. Results suggested that, (1) In the dyeing wastewater, the occurrence characteristic of COD was: soluble>supra colloidal>colloidal>settleable; However, for protein, the supra colloidal was dominant, followed by the soluble. The feature of the polysaccharide was consistent with COD’s. In the wastewater, 29.66% of COD could be attributed to proteins and 3.45% of the COD could be attributed to polysaccharides. (2) The relationship among the forms of COD in the primary sedimentation tank, aerobic tank, secondary sedimentation tank, and reverse osmosis-treated concentrated effluent was consistent, that was: soluble>colloidal>supra colloidal>settleable. (3) In the primary sedimentation tank, the settleable COD was almost completely removed; In the aerobic tank, the residual super colloidal COD was not much; After MBR-RO treatment, the COD in the reverse osmosis concentrated water was almost dissolved and only a little presented in other forms.

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