scholarly journals MODERNIZATION OF DEVICES FOR PURIFICATION OF AIR FROM SOLID HIGH-DISPERSED AEROSOLS

2020 ◽  
Vol 10 (2) ◽  
pp. 16-21
Author(s):  
Svetlana M. PURING ◽  
Denis N. VATUZOV
Keyword(s):  
Boundary Layer ◽  
Solid Particles ◽  
Mutual Arrangement ◽  
Particle Capture ◽  
Turbulence Scale ◽  
Particle Coarsening ◽  
Effi Ciency ◽  
Coagulation Of Particles

A device for cleaning solid particles with a dispersion of 0.1 μm is proposed. The principle of the apparatus is based on coagulation of particles on slots perforated in the form of slots, using irrigation of contaminated air with water through nozzles with a dispersed composition from 2.0 microns to 10 microns. When a threephase fl ow passes through the slots of the fi rst separator plate, turbulent coagulation occurs due to turbulence of the fl ow in streams with a small turbulence scale, which leads to particle coarsening. When the jet runs onto the second plate, a boundary layer is formed that has an increased viscosity to the components of the jet. Viscosity is formed due to the sedimentation and mixing of water particles and dust (including coarsened) on the surface of the second plate, where particles are mainly deposited. The dependences of the apparatus effi ciency on the width of the slots and their mutual arrangement on the fi rst and second plates, the combination of which provides a mode of increased coagulation and high effi - ciency of particle capture by the apparatus, are revealed.

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.

Two months of measurements with an autonomous thermodynamic Raman lidar in Lindenberg

2021 ◽  
Author(s):  
Diego Lange Vega ◽  
Andreas Behrendt ◽  
Volker Wulfmeyer
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Inversion Layer ◽  
Measurement Range ◽  
High Accuracy ◽  
Free Troposphere ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Geophysical Research ◽  
Turbulence Scale

<p>Between 15 July 2020 and 19 September 2021, the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS) collected data at the Lindenberg Observatory of the Deutscher Wetterdienst (DWD), including temperature and water vapor mixing ratio with a high temporal and range resolution.</p> <p>During the operation period, very stable 24/7 operation was achieved, and ARTHUS demonstrated that is capable to observe the atmospheric boundary layer and lower free troposphere during both daytime and nighttime up to the turbulence scale, with high accuracy and precision, and very short latency. During nighttime, the measurement range increases even up to the tropopause and lower stratosphere.</p> <p>ARTHUS measurements resolve the strength of the inversion layer at the planetary boundary layer top, elevated lids in the free troposphere, and turbulent fluctuations in water vapor and temperature, simultaneously (Lange et al., 2019, Wulfmeyer et al., 2015). In addition to thermodynamic variables, ARTHUS provides also independent profiles of the particle backscatter coefficient and the particle extinction coefficient from the rotational Raman signals at 355 nm with much better resolution than a conventional vibrational Raman lidar.</p> <p>At the conference, highlights of the measurements will be presented. Furthermore, the statistics of more than 150 comparisons with local radiosondes will be presented which confirm the high accuracy of the temperature and moisture measurements of ARTHUS.</p> <p><strong><em>Acknowledgements</em></strong></p> <p>The development of ARTHUS was supported by the Helmholtz Association of German Research Centers within the project Modular Observation Solutions for Earth Systems (MOSES). The measurements in Lindenberg were funded by DWD.</p> <p><strong><em>References </em></strong></p> <p>Lange, D., Behrendt, A., and Wulfmeyer, V. (2019). Compact operational tropospheric water vapor and temperature Raman lidar with turbulence resolution. <em>Geophysical Research Letters</em>, 46. https://doi.org/10.1029/2019GL085774</p> <p>Wulfmeyer, V., R. M. Hardesty, D. D. Turner, A. Behrendt, M. P. Cadeddu, P. Di Girolamo, P. Schlüssel, J. Van Baelen, and F. Zus (2015), A review of the remote sensing of lower tropospheric thermodynamic profiles and its indispensable role for the understanding and the simulation of water and energy cycles, <em>Rev. Geophys.</em>, 53,819–895, doi:10.1002/2014RG000476</p>

Large-eddy Simulation of the Dispersion of Solid Particles in a Turbulent Boundary Layer

2006 ◽  
Vol 121 (2) ◽  
pp. 283-311 ◽  
Author(s):  
Ivana Vinkovic ◽  
Cesar Aguirre ◽  
Michel Ayrault ◽  
Serge Simoëns
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Large Eddy Simulation ◽  
Solid Particles ◽  
Eddy Simulation ◽  
Large Eddy

Deposition of solid particles in laminar boundary layer on a flat plate

2009 ◽  
Vol 47 (6) ◽  
pp. 892-901 ◽  
Author(s):  
A. I. Kartushinsky ◽  
I. A. Krupensky ◽  
S. V. Tisler ◽  
M. T. Hussainov ◽  
I. N. Shcheglov
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Laminar Boundary Layer ◽  
Solid Particles

scholarly journals Analysis of the influence of temperature inversions on the ecological situation in Krasnoyarsk

2021 ◽  
Author(s):  
A.V. Dergunov ◽  
O.E. Yakubailik
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Surface Layer ◽  
Wind Speed ◽  
Lower Layer ◽  
Meteorological Data ◽  
Forecast Model ◽  
Solid Particles ◽  
Temperature Inversions ◽  
The Relationship

The paper analyzes the meteorological conditions in the city of Krasnoyarsk in the period from January 1, 2019, to December 31, 2020. The relationship between temperature inversions in the surface layer of the atmosphere and air pollution by suspended solid particles PM25 is investigated. The paper uses a set of meteorological data of the NCEP GFS weather forecast model on the air temperature on three isobaric surfaces of 1000, 925, and 850 Mb; on wind gusts and the height of the atmospheric boundary layer. Data on PM25 solid particle concentrations and wind speed are provided by the air monitoring system of the KSC SB RAS. The relationship between the presence of temperature inversions in the lower layer of the atmosphere and periods of significant air pollution is shown, as well as the dependence of changes in wind speed and the height of the boundary layer of the atmosphere with changes in the average daily PM25 concentration. The results of the data analysis allow us to conclude that there is a high degree of correlation between these parameters. The possibility of using the meteorological data of the NCEP GFS model to study the surface layer of the atmosphere and the periods of its pollution, predicting the deterioration of the environmental situation in Krasnoyarsk, is demonstrated.

scholarly journals Large-Eddy Simulations of Stability-Varying Atmospheric Boundary Layer Flow over Isolated Buildings

2021 ◽  
Author(s):  
Hyeyum Hailey Shin ◽  
Domingo Muñoz-Esparza ◽  
Jeremy A. Sauer ◽  
Matthias Steiner
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Atmospheric Stability ◽  
Lateral Side ◽  
Mean Flow ◽  
Turbulence Scale ◽  
Advection Scheme ◽  
Large Eddy ◽  
Flow Features ◽  
Induced Flow

AbstractThis study explores the response of flow around isolated cuboid buildings to variations in the incoming turbulence arising from changes in atmospheric boundary layer (ABL) stability using a building-resolving large-eddy simulation (LES) technique with explicit representation of building effects through an immersed body force method. An extensive suite of LES for a neutral ABL with different model resolution and advection scheme configurations reveals that at least 6, 12, and 24 grid points per building side are required in order to resolve building-induced vortex shedding, mean-flow features, and turbulence statistics, respectively, with an advection scheme of a minimum of third-order. Using model resolutions that meet this requirement, 21 building-resolving simulations are performed under varying atmospheric stability conditions, from weakly stable to convective ABLs, and for different building sizes (H), resulting in LABL/H ≈ 0.1 – 10, where LABL is the integral length scale of the incoming ABL turbulence. The building-induced flow features observed in the canonical neutral ABL simulation, e.g., the upstream horseshoe vortex and the downstream arch vortex, gradually weaken with increasing surface-driven convective instability due to the enhancement of background turbulent mixing. As a result, two local turbulence kinetic energy peaks on the lateral side of the building in non-convective cases are merged into a single peak in strong convective cases. By considering the ABL turbulence scale and building size altogether, it is shown that the building impact decreases with increasing LABL/H, as coherent turbulent structures in the ABL become more dominant over a building-induced flow response for LABL/H > 1.

Simulation the sedimentation of a finely dispersed medium under the impact of pressure waves

2012 ◽  
Vol 9 (2) ◽  
pp. 80-85
Author(s):  
C.I. Mikhaylenko ◽  
Yu.R. Valeeva
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Disperse System ◽  
Dispersion Medium ◽  
Solid Particles ◽  
Pressure Waves ◽  
Dispersed Particles ◽  
Coagulation Of Particles ◽  
Dispersed Medium ◽  
The Impact

A mathematical model for a disperse system of gas-solid particles when passing pressure waves is decribed. The following assumptions are made: dispersed particles are capable of coagulation with increasing concentration; the dispersed particles are acted upon by the Stokes forces on the side of the dispersion medium and by gravity. The results of numerical simulation of the processes of sedimentation of a dispersed medium are presented. It is shown that one of the mechanisms of precipitation of fine disperced medium can be coagulation of particles during the passage of pressure waves.

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