To Increase the Degree of Capture of Fine-Grained Dust Particles, the Development of a Mathematical Model of the Motion and Separation of Solid Particles during Dynamic Regeneration

2020 ◽  
Vol 24 (5) ◽  
pp. 2112-2118
Author(s):  
Malika Akhmedova
Keyword(s):  
Mathematical Model ◽  
Solid Particles ◽  
Dust Particles ◽  
Fine Grained

scholarly journals Mathematical Model of Airflow and Solid Particles Transport in The Human Nasal Cavity

2021 ◽  
Vol 16 (2) ◽  
pp. 349-366
Author(s):  
P.V. Trusov ◽  
N.V. Zaitseva ◽  
M.Yu. Tsinker ◽  
A.V. Nekrasova
Keyword(s):  
Mathematical Model ◽  
Nasal Cavity ◽  
Particle Diameter ◽  
Suspended Particles ◽  
Machine Building ◽  
Solid Particles ◽  
Dust Particles ◽  
Multiphase Mixture ◽  
Different Temperatures ◽  
The Right

As part of the mathematical model of the human respiratory system, a submodel is considered for the study of the non-steady airflow with solid particles (suspended particulate matter (PM) / dust particles) and the deposition of particles of various sizes in the human nasal cavity. It is assumed that the nasal cavity is divided by the bone-cartilaginous septum into two symmetrical (relative to the nasal septum) parts; the average geometry of the right part of the human nasal cavity is considered. The inhaled air is considered as a multiphase mixture of homogeneous single-component gas and solid dust particles. The Eulerian-Lagrangian approach to modeling the motion of a multiphase mixture is used: a viscous liquid model is used to describe the motion of the carrier gas phase; the carried phase (dust particles) is modeled as separate inclusions of various sizes. The process of heating the inhaled air due to its contact with the walls is also taken into account. The features of the unsteady flow of a multiphase air mixture with dust particles were obtained using Ansys CFX for several scenarios. It has been noted that when studying the airflow in the nasal cavity, it is necessary to take into account the presence of turbulence, for which it is proposed to use the k-ω model. The velocity fields of inhaled air in the nasal cavity have been obtained; presented temperature distributions in the nasal cavity at different time points; made estimates of air heating at different temperatures of inhaled air; gave estimates of the proportion of deposited particles in the nasal cavity depending on the particle size for real machine-building production; presented trajectories of movement of suspended particles. Thus, it is shown that more than 99.7 % of particles with a diameter of more than 10 microns deposit in the human nasal cavity; as the particle diameter and mass decrease, the proportion of deposited particles decreases. Suspended particles with a size of less than 2.5 microns almost do not deposit in the nasal cavity. They can penetrate deeper into the lower airways and lungs of a person with the inhaled air and, having fibrogenic and toxic effect, can cause diseases. The results obtained are in good agreement with the results of individual studies performed by other scientists. Further development of the model involves studying airflow in the human lungs and modeling the formation of diseases caused by the harmful effects of environmental factors (including dust particles) entering the human body by inhalation.

Investigation of the different particle size dust releases from rigid filter candles during pulse-jet cleaning

2021 ◽  
pp. 095440622110179
Author(s):  
Xin Luan ◽  
Zhongli Ji ◽  
Longfei Liu ◽  
Ruifeng Wang
Keyword(s):  
Particle Size ◽  
Critical Role ◽  
Operating Conditions ◽  
Solid Particles ◽  
Dust Particles ◽  
Cleaning Efficiency ◽  
Term Operation ◽  
Cleaning Performance ◽  
Experimental Apparatus ◽  
Pulse Jet

Rigid filters made of ceramic or metal are widely used to remove solid particles from hot gases at temperature above 260 °C in the petrochemical and coal industries. Pulse-jet cleaning of fine dust from rigid filter candles plays a critical role in the long-term operation of these filters. In this study, an experimental apparatus was fabricated to investigate the behavior of a 2050 mm filter candle, which included monitoring the variation of pressure dynamic characteristics over time and observing the release of dust layers that allowed an analysis of the cleaning performance of ISO 12103-1 test dusts with different particle size distributions. These results showed the release behavior of these dusts could be divided into five stages: radial expansion, axial crack, flaky release, irregular disruption and secondary deposition. The cleaning performance of smaller sized dust particles was less efficient as compared with larger sized dust particles under the same operating conditions primarily because large, flaky-shaped dust aggregates formed during the first three stages were easily broken into smaller, dispersed fragments during irregular disruption that forced more particles back to the filter surface during secondary deposition. Also, a “low-pressure and long-pulse width” cleaning method improved the cleaning efficiency of the A1 ultrafine test dust from 81.4% to 95.9%.

scholarly journals Two-Phase Dusty Fluid Flow Along a Rotating Axisymmetric Round-Nosed Body

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Sadia Siddiqa ◽  
Naheed Begum ◽  
M. A. Hossain ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Boundary Layer ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Solid Particles ◽  
Dust Particles ◽  
Computational Domain ◽  
Two Phase ◽  
Carrier Fluid ◽  
Boundary Layer Equations ◽  
Implicit Finite Difference

This article is concerned with the class of solutions of gas boundary layer containing uniform, spherical solid particles over the surface of rotating axisymmetric round-nosed body. By using the method of transformed coordinates, the boundary layer equations for two-phase flow are mapped into a regular and stationary computational domain and then solved numerically by using implicit finite difference method. In this study, a rotating hemisphere is used as a particular example to elucidate the heat transfer mechanism near the surface of round-nosed bodies. We will investigate whether the presence of dust particles in carrier fluid disturbs the flow characteristics associated with rotating hemisphere or not. A comprehensive parametric analysis is presented to show the influence of the particle loading, the buoyancy ratio parameter, and the surface of rotating hemisphere on the numerical findings. In the absence of dust particles, the results are graphically compared with existing data in the open literature, and an excellent agreement has been found. It is noted that the concentration of dust particles’ parameter, Dρ, strongly influences the heat transport rate near the leading edge.

scholarly journals Elastic Properties of Natural Sea Surface Films Incorporated with Solid Dust Particles: Model Baltic Sea Studies

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Adriana Z. Mazurek ◽  
Stanisław J. Pogorzelski
Keyword(s):  
Baltic Sea ◽  
Surface Film ◽  
Contact Angles ◽  
Solid Particles ◽  
Sea Surface ◽  
Dust Particles ◽  
Surface Films ◽  
Particle Removal ◽  
Water Contact ◽  
Composite Surface

Floating dust-originated solid particles at air-water interfaces will interact with one another and disturb the smoothness of such a composite surface affecting its dilational elasticity. To quantify the effect, surface pressure (Π) versus film area (A) isotherm, and stress-relaxation (Π-time) measurements were performed for monoparticulate layers of the model hydrophobic material (of μm-diameter and differentiated hydrophobicity corresponding to the water contact angles (CA) ranging from 60 to 140°) deposited at surfaces of surfactant-containing original seawater and were studied with a Langmuir trough system. The composite surface dilational modulus predicted from the theoretical approach, in which natural dust load signatures (particle number flux, daily deposition rate, and diameter spectra) originated from in situ field studies performed along Baltic Sea near-shore line stations, agreed well with the direct experimentally derived data. The presence of seawater surfactants affected wettability of the solid material which was evaluated with different CA techniques applicable to powdered samples. Surface energetics of the particle-subphase interactions was expressed in terms of the particle removal energy, contact cross-sectional areas, collapse energies, and so forth. The hydrophobic particles incorporation at a sea surface film structure increased the elasticity modulus by a factor K (1.29–1.58). The particle-covered seawater revealed a viscoelastic behavior with the characteristic relaxation times ranging from 2.6 to 68.5 sec.

Influence of Alteration of Variance of Normal Distribution of Microsphere Cavity Radius on the Proccess of Helium Sorption by Microspheres

2011 ◽  
Vol 6 (2) ◽  
pp. 24-27
Author(s):  
Anton S. Vereshchagin
Keyword(s):  
Mathematical Model ◽  
Initial Data ◽  
Normal Distribution ◽  
Theoretical Investigation ◽  
Solid Particles ◽  
Uneven Distribution ◽  
Cavity Radius

Theoretical investigation of the proccess of helium sorption by hollow permeable solid particles (microspheres) is done. Mathematical model of the proccess is derived under the assumption of uneven distribution of radius of microsphere cavity. It's shown that the rate of sorption changes insignificantly for investigated ranges of initial data within normal distribution of microsphere cavity radius

scholarly journals Interstellar and Solar System organic matter preserved in interplanetary dust

2015 ◽  
Vol 11 (A29B) ◽  
pp. 426-426
Author(s):  
Scott Messenger ◽  
K. Nakamura-Messenger
Keyword(s):  
Organic Matter ◽  
Solar System ◽  
Carbonaceous Material ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Fine Grained ◽  
Mass Fractionation ◽  
Current State ◽  
Short Period

AbstractInterplanetary dust particles (IDPs) collected in the Earths stratosphere derive from collisions among asteroids and by the disruption and outgassing of short-period comets. Chondritic porous (CP) IDPs are among the most primitive Solar System materials. CP-IDPs have been linked to cometary parent bodies by their mineralogy, textures, C-content, and dynamical histories. CP-IDPs are fragile, fine-grained (< um) assemblages of anhydrous amorphous and crystalline silicates, oxides and sulfides bound together by abundant carbonaceous material. Ancient silicate, oxide, and SiC stardust grains exhibiting highly anomalous isotopic compositions are abundant in CP-IDPs, constituting 0.01-1% of the mass of the particles. The organic matter in CP-IDPs is isotopically anomalous, with enrichments in D/H reaching 50x the terrestrial SMOW value and 15N/14N ratios up to 3x terrestrial standard compositions. These anomalies are indicative of low T (10-100 K) mass fractionation in cold molecular cloud or the outermost reaches of the protosolar disk. The organic matter shows distinct morphologies, including sub-um globules, bubbly textures, featureless, and with mineral inclusions. Infrared spectroscopy and mass spectrometry studies of organic matter in IDPs reveals diverse species including aliphatic and aromatic compounds. The organic matter with the highest isotopic anomalies appears to be richer in aliphatic compounds. These materials also bear similarities and differences with primitive, isotopically anomalous organic matter in carbonaceous chondrite meteorites. The diversity of the organic chemistry, morphology, and isotopic properties in IDPs and meteorites reflects variable preservation of interstellar/primordial components and Solar System processing. One unifying feature is the presence of sub-um isotopically anomalous organic globules among all primitive materials, including IDPs, meteorites, and comet Wild-2 samples returned by the Stardust mission. We will present an overview of the current state of understanding of the properties and origins of organic matter in primitive IDPs.

Laser Measurements of Fly Ash Rebound Parameters for Use in Trajectory Calculations

1987 ◽  
Vol 109 (4) ◽  
pp. 535-540 ◽  
Author(s):  
W. Tabakoff ◽  
M. F. Malak
Keyword(s):  
Gas Flow ◽  
Initial Conditions ◽  
Incidence Angle ◽  
Equations Of Motion ◽  
Solid Particles ◽  
Dust Particles ◽  
Laser Doppler Velocimeter ◽  
Laser Measurements ◽  
Flow Through ◽  
Small Dust

This paper describes an experimental method used to find particle restitution coefficients. The equations that govern the motion of solid particles suspended by a compressible gas flow through a turbomachine depend on the restitution coefficients. Analysis of the data obtained by a laser-Doppler velocimeter (LDV) system of the collision phenomenon gives the restitution ratios as a function of the incidence angle. From these ratios, the particle velocity components after collision are computed and used as the initial conditions to the solution of the governing equations of motion for particle trajectories. The erosion of metals impacted by small dust particles can be calculated by knowing the restitution coefficients. The alloy used in this investigation was 410 stainless steel.

Experimental and Theoretical Study on Melting Kinetics of Spherical Aluminum Particles in Liquid Aluminum

2015 ◽  
Vol 1765 ◽  
pp. 139-144
Author(s):  
Marco Ramírez-Argáez ◽  
Enrique Jardón ◽  
Carlos González-Rivera
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Transfer Coefficient ◽  
Process Analysis ◽  
Convective Heat Transfer Coefficient ◽  
Melting Process ◽  
Solid Particles ◽  
Melting Time ◽  
Melting Kinetics ◽  
Kinetics Of

ABSTRACTIn this study a process analysis of the melting process of solid particles in a bath of same composition is performed using both experimental information and theoretical computations. An experimental setup was used to measure the thermal histories and to follow the evolution with time of the size of solid metallic spherical particles being melted in a metallic bath of same composition. For such a purpose, pure aluminum was used during the experiments for both solid particles and liquid bath. A mathematical model was also developed based on first principles of heat transfer to simulate the melting kinetics of a cold metallic spherical particle immersed in a hot liquid bath of same composition. The mathematical model was reasonably validated when compared against the experimental results obtained in this work. A process analysis of the melting process was performed to determine the effect of the initial temperature and size of the solid particle, the bath temperature and the convective heat transfer coefficient on the melting time and on the energy consumption.The analysis showed that the variable presenting the most significant effect on both the melting time and the energy consumption is the convective heat transfer coefficient between the particle and the bath, since an increment in such a parameter accelerates the melting process and saves energy. Therefore, proper stirring of the bath is highly recommended to enhance the melting of metallic alloying additions in the metallic baths.

Mathematical model of energy conversion mechanism in screw centrifugal pump based on load criteria of blade airfoil

2017 ◽  
Vol 34 (7) ◽  
pp. 2168-2188 ◽  
Author(s):  
Hui Quan ◽  
Baiheng Fu ◽  
Rennian Li ◽  
Guangxian Li ◽  
Zhengjie Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Energy Transfer ◽  
Energy Conversion ◽  
Centrifugal Pump ◽  
Lift Coefficient ◽  
Energy Conversion Efficiency ◽  
Solid Particles ◽  
Content Type ◽  
Wrap Angle

Purpose To analyze the work principle and capacity of energy conversion in each segment of profile lines, the energy transfer from impeller to transmission medium is separated into head coefficient and load coefficient to analyze the energy transfer process. The concepts of airfoil lift coefficient and drag coefficient are used; the third manifestation of the Euler equations is used as well. Design/methodology/approach The numerical simulation of energy conversion mechanism based on load criteria of vane airfoil has been established in screw centrifugal pump to explain its energy conversion mechanism in an impeller. Upon this basis, the velocity and pressure along the entire blade are investigated through the numerical simulation of internal solid–liquid flow in the pump. The energy conversion process under load criteria in the blade airfoil has also been obtained. Findings The research suggests that the mathematical model of energy conversion mechanism based on the load criteria of the vane airfoil is reliable in the screw centrifugal pump. The screw centrifugal blade has twice or even several times the wrap angle than the ordinary centrifugal blade. It is a large wrap angle that forms the unique flow channel which lays the foundation for solid particles to pass smoothly and for soft energy conversion. At the same time, load distribution along the profile line on the long-screw centrifugal blade is an important factor affecting the energy conversion efficiency of the impeller. Originality/value The quantitative analysis method of energy in the screw centrifugal pump can help the pump designer improve certain features of the pump and shorten the research cycle.

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