scholarly journals RESEARCH INTO THE CLEANING EFFICIENCY OF 300 M3/H MAINTAINED BY THE SPIRAL MULTI-CHANNEL CYCLONE IN THE PROCESS OF REMOVING SOLID PARTICLES OF <20 ΜM / 300 M3/H NAŠUMO SPIRALINIO DAUGIAKANALIO CIKLONO VALYMO EFEKTYVUMO TYRIMAS, ŠALINANT < 20 ΜM KIETĄSIAS

2014 ◽  
Vol 6 (4) ◽  
pp. 373-378
Author(s):  
Pranas Baltrėnas ◽  
Diana Platova
Keyword(s):  
Particulate Matter ◽  
Gas Flow ◽  
Experimental Studies ◽  
Flow Distribution ◽  
Experimental Tests ◽  
Solid Particles ◽  
Treatment Efficiency ◽  
Cleaning Efficiency ◽  
Ultrafine Particulate Matter ◽  
Spiral Casing

Tests on the cleaning efficiency of an experimental spiral cyclone have been conducted to determine the removal efficiency of the solid particles the dispersion of which makes &lt;20 µm in the streamlined multi-channel cyclone. The introduced device is adapted to removing ultrafine particulate matter from contaminated air (gas) flow. A multi-channel cyclone with spiral casing has been designed at the Department of Environmental Protection (DEP) of Vilnius Gediminas Technical University. Experimental studies have disclosed that air (gas) flow cleaning efficiency of the spiral multi-cyclone (capacity 300 m3) depend on the internal structure of the device, i.e. on the number of channels and air (gas) flow distribution ratio of transit and peripheral channels. Also, the treatment efficiency of the applied equipment has been evaluated removing solid particles of different nature. AFA-VP-20 filters have been employed for conducting experimental tests. The obtained results have disclosed that solid granite particles – 95.1%, glass – 91.4% and wood – 92.2% are removed most effectively. Eksperimentiniai spiralinio ciklono valymo efektyvumo tyrimai atliekami siekiant nustatyti kietųjų dalelių, kurių dispersija x &lt; 20 μm, pašalinimo efektyvumą patobulintame daugiakanaliame ciklone. Minėtas įrenginys pritaikytas itin smulkioms kietosioms dalelėms iš užteršto oro (dujų) srauto pašalinti. Daugiakanalis ciklonas, turintis spiralinį korpusą, sukurtas Vilniaus Gedimino technikos universiteto (VGTU) Aplinkos apsaugos katedroje (AAK). Eksperimentinių tyrimų metu nustatytas spiralinio daugiakanalio ciklono (našumas 300 m3/h) oro (dujų) srauto valymo efektyvumas priklausomai nuo vidinės įrenginio konstrukcijos, t. y. nuo kanalų skaičiaus ir oro (dujų) srauto pasiskirstymo į tranzitinį ir periferinį kanalus santykio. Taip pat įvertintas įrenginio valymo efektyvumas, šalinant skirtingos prigimties kietąsias daleles. Eksperimentiniams bandymams atlikti naudoti AFA-VP-20 filtrai. Remiantis bandymų rezultatais, nustatyta, kad efektyviausiai šalinamos granito kietosios dalelės – 95,1 %, stiklas – 91,4 %, mediena – 92,2 %.

scholarly journals Experimental and Numerical Studies of Hydrodynamics of Gas Flow through Orthogonal Networks

2018 ◽  
Author(s):  
Grzegorz Wałowski
Keyword(s):  
Kinetic Energy ◽  
Dissipation Rate ◽  
Gas Flow ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Cfd Modeling ◽  
Numerical Studies ◽  
Isotropic Porous Material ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through

Simulation programs contain Computational Fluid Dynamics - CFD codes and are a useful tool used for gas flow through porous materials. Conducting numerical simulations allows for detailed analysis of hydrodynamic phenomena. The results of numerical modeling should always be verifiable based on experimental data. Only their compliance with the results of experimental tests is a determinant of the correctness of the applied method. As part of the work, experimental studies of hydrodynamics of gas flow through an isotropic porous material were carried out and numerical simulation for material of the same shape was used. In the CFD modeling Kolmogorov's hypothesis for the transport of kinetic energy of turbulence k and transport of dissipation rate of kinetic energy of turbulence &epsilon; was used.

Influence of suspended solid particles on gas-liquid mass transfer coefficient in a system stirred by double impellers

2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Anna Kiełbus-Rąpała ◽  
Joanna Karcz
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
High Speed ◽  
Gas Flow ◽  
Research Work ◽  
Experimental Studies ◽  
Solid Particles ◽  
Solid Concentration ◽  
Volumetric Mass Transfer Coefficient

AbstractThe aim of the research work was to investigate the effect of the presence and concentration of solid particles on the gas-liquid volumetric mass transfer coefficient in a mechanically stirred gas-solid-liquid system. Experimental studies were conducted in a tall vessel of the diameter of 0.288 m, equipped with two designs of double stirrers. Three high-speed stirrers were used: A 315, Smith turbine, and Rushton turbine. The following operating parameters were changed: gas flow rate, stirrer speed, and solid concentration. The volumetric mass transfer coefficient was determined using the dynamic gassing-out method. In the range of the measurements conducted, this coefficient was strongly affected by both the presence and the concentration of particles in the system. Generally, a low concentration of particles in the system, equal to 0.5 mass %, caused an increase of the volumetric mass transfer coefficient values for both stirrer configurations compared to a system without solids whilst more particles (2.5 mass %) caused a decrease of this coefficient. It could be supposed that an increase of slurry viscosity affected the decrease of the volumetric mass transfer coefficient at higher solid concentration. An empirical correlation was proposed for volumetric mass transfer coefficient prediction. Its parameters were fitted using experimental data.

scholarly journals Environmental Particulate Air Pollution Exposure and the Oxidative Stress Responses: A Brief Review of the Impact on the Organism and Animal Models of Research

2021 ◽  
Author(s):  
Pauline Brendler Goettems Fiorin ◽  
Mirna Stela Ludwig ◽  
Matias Nunes Frizzo ◽  
Thiago Gomes Heck
Keyword(s):  
Oxidative Stress ◽  
Particulate Matter ◽  
Stress Responses ◽  
Cellular Stress ◽  
Size Composition ◽  
Solid Particles ◽  
Cellular Stress Response ◽  
Liquid Droplets ◽  
Shock Proteins ◽  
Ultrafine Particulate Matter

Particulate matter (PM) is a mixture of solid particles and liquid droplets found in the air, and it is one of the most harmful air pollutants. When inhaled, it affects the pulmonary system, cardiovascular systems, and other tissues. The size, composition, and deposition of PM, mainly related to fine and ultrafine particulate matter, are factors that determine the harmful effects of exposure to particles. Among the main effects is the inducer of ROS production, and consequently oxidative tissue damage in target organs and other responses, mediated by inflammatory cytokines and cellular stress response. The main pathway through which particles are potent mediators of oxidative stress is the damage caused to DNA and lipid molecules, whereas the pro-inflammatory response involves an immune response against PM, which in turn, it is related to cell stress responses observed by heat shock proteins (HSPs) expression and release. Thus, the ability of an organism to respond to PM inhalation requires anti-oxidative, anti-inflammatory, and cellular stress defenses that can be impaired in susceptible subjects as people with chronic diseases as diabetes and obesity. In this chapter, we discuss the mechanistic aspects of PM effects on health and present some animal research models in particle inhalation studies.

scholarly journals The Numerical Modeling of Gas Movement in a Single Inlet New Generation Multi-Channel Cyclone Separator

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8092
Author(s):  
Aleksandras Chlebnikovas ◽  
Artūras Kilikevičius ◽  
Jaroslaw Selech ◽  
Jonas Matijošius ◽  
Kristina Kilikevičienė ◽  
...  
Keyword(s):  
Gas Flow ◽  
Numerical Models ◽  
Research Process ◽  
Solid Particles ◽  
Gas Flows ◽  
Cyclone Separator ◽  
Cleaning Efficiency ◽  
Gas Cleaning ◽  
Viscosity Models ◽  
New Generation

The work of traditional cyclones is based on the separation of solid particles using only the centrifugal forces. Therefore, they do not demonstrate high gas-cleaning efficiency, particularly in the cases where gas flows are polluted with fine solid particles (about 20 µm in diameter). The key feature of a new-generation multi-channel cyclone separator’s structure is that its symmetrical upgraded curved elements, with openings cut with their plates bent outwards, make channels for the continuous movement of the gas flows from the inflow opening to the central axis. The smoke flue of the vertical gas outflow is located near the cover of the separating chamber. The present work is aimed at studying the applicability of two various viscosity models and their modified versions to simulate aerodynamic processes in an innovative design for a multi-channel cyclone separator with a single inflow, using the computational fluid dynamics. The research results obtained in the numerical simulation are compared to the experimental results obtained using a physical model. The main purpose of this study is to provide information on how the new design for the multi-channel cyclone affects the distribution of gas flow in the cyclone’s channels. The modified viscosity models, k-ε and k-ω, and computational meshes with various levels of detailed elaboration were analyzed. The developed numerical models of a single-inlet multi-channel cyclone separator allow the researchers to describe its advantages and possible methods of improving its new structure. The developed models can be used for simulating the fluid cleaning phenomenon in the improved fourth-channel cyclone separator and to optimize the whole research process.

Researches of Aggressive Gas Flow Cleaning from Wood Ash Particu-late Matter in the Multi-Channel Cyclone

2017 ◽  
Author(s):  
Aleksandras Chlebnikovas ◽  
Pranas Baltrėnas
Keyword(s):  
Flow Velocity ◽  
Gas Flow ◽  
Aerodynamic Resistance ◽  
Experimental Tests ◽  
Wood Ash ◽  
Cleaning Efficiency ◽  
Gas Cleaning ◽  
Place Studies ◽  
Aerodynamic Parameters ◽  
Gas Flow Velocity

The studies examined the gas flow aerodynamic parameters and treatment efficiency from the wood ash particulate matter, also an adhesion dependencies in multi-channel cyclone using aggressive gas flow – temperature up to 75 °C and relative humidity more than 95%. Researches of gas flow velocity and cyclone aerodynamic resistance in case of different average gas flow velocity in the cyclone and particle adhesion analysis inside the cyclone. Cyclones work is based on centrifugal forces and additionally resulting filtration process operation. Due to the interaction between inlet flow from the (peripheral) channel coming next and the flow following the direction towards the axis of the cyclone along the channel (transit), additional filtration takes place. Studies was carried out the prototype of multi-channel cy-clone, which is used with curvilinear quarter-rings with opening slot folded at an angle, so that the peripheral and transit flows are equal to each other. The aim – to determine the multi-channel cyclone aerodynamic parameters, and their dependencies, to make aggressive gas flow and to analyse the wood ash particles adhesion and its impact to multi-channel cyclone operation by occluding device's internal design. The average velocity of gas flow was equal to 8, 12 and 16 m/s, the highest aerodynamic resistance was equal to 410 Pa, which was determined in the case at 16 m/s. Based on experimental tests, PM which the diameter up to 20 microns, the gas cleaning efficiency is above 85% when inlet concentration was 5 g/m3.

scholarly journals Investigation on particulate matter and gas motion processes in the advanced multi-channel cyclone-separator with secondary gas inlets

2021 ◽  
Vol 27 (1) ◽  
pp. 200550-0
Author(s):  
Pranas Baltrėnas ◽  
Andrea Crivellini ◽  
Terese Leonavičienė ◽  
Aleksandras Chlebnikovas
Keyword(s):  
Particulate Matter ◽  
Gas Flow ◽  
Experimental Studies ◽  
Flow Conditions ◽  
Computational Accuracy ◽  
Flow Motion ◽  
The Impact ◽  
Omega Model ◽  
Principal Elements

Research into gas flow motion as a transported phase and pollutant – particulate matter (PM) is of crucial importance, their changes in particular areas of the object require knowledge of improving the apparatus. A cyclone is considered one of the most popular devices due to the new modified multi-channel design that involves combined separation and filtration phenomena. The findings of an accurate numerical model provide an opportunity to verify long-term experimental studies. In addition, it is possible to determine the impact of the designed principal elements of the structure comprising secondary gas inlets, inner slits and the convex bottom on gas and PM motion through verification conducting experimental research. The study focuses on simulating the upgraded cyclone using the SST k-omega model. The research has been conducted under the specified gas flow conditions such as high temperature and relative humidity (aggressive) gas and presents the results of the physical model to compare with. To achieve greater computational accuracy, a digital model of the cyclone made of specific volumetric elements has been developed thus expanding the grid and stepping to form the boundary zone. As a result, numerical simulation results differ by no more than 12.8% compared to the experimental studies results.

Numerical simulation and experimental tests of the filter with a rotating cylindrical perforated filter element

2020 ◽  
pp. 095440622095034
Author(s):  
Volodymyr Brazhenko ◽  
Ievgen Mochalin
Keyword(s):  
Numerical Simulation ◽  
Filter Design ◽  
Technical Problem ◽  
Fluid Motion ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Filter Element ◽  
Cleaning Efficiency ◽  
Simulation Results ◽  
Almost All

There is a need to clean various liquids of solid impurities in almost all areas of human activity. The filter design with a rotating cylindrical perforated filter element was proposed to address this topical technical problem. Its work based on the principle of rotational filtration. The experimental studies demonstrated that with a rotating cylindrical perforated filter element could remove more than 90% of the admixture particles. This took place in defined fluid motion modes, which characterized by the dimensionless Reynolds numbers. In the present study, numerical simulation was carried out for an investigation of the hydraulic oil motion and solid admixture particles' motion in the filter. The simulation results showed a local increase velocity in the holes of the perforated filter element. It entails the passage of a very small particle number into the filtrate. A comparison of the numerical simulation results of filter cleaning efficiency with the data of physical experiments showed a rather good agreement, the discrepancy between which is less than 9%.

scholarly journals Research of the Aerodynamic Parameters in a Special Cyclone with Secondary Inlets

2017 ◽  
Vol 9 (4) ◽  
pp. 400-405
Author(s):  
Aleksandras Chlebnikovas ◽  
Pranas Baltrėnas
Keyword(s):  
Particulate Matter ◽  
Gas Flow ◽  
Fine Particulate Matter ◽  
Centrifugal Forces ◽  
Cleaning Efficiency ◽  
Gas Treatment ◽  
Fine Particulate ◽  
Process Operation ◽  
Aerodynamic Parameters ◽  
Gas Flow Velocity

Special cyclone – gas treatment device which can be applied to remove the fine particulate matter bigger than 2 micrometres from aggressive gas flow at a temperature of 50–145 °C and a relative humidity of more than 95% and can be achieved the cleaning efficiency over 90%. Cyclone work is based on centrifugal forces and the resulting additional filtration process operation. Cyclone structure equipped with primary and secondary gas flow inflows through which gas dispersed flow is supplied parallel to all channels of the cyclone. Analysed modified multi-channel cyclone can be effectively treated from fine particulate matter, during the cleaning of aggressive gas flow an adhesion/cohesion phenomena could be reduced. Research of aerodynamic parameters it’s the first step of studies to determine the optimal case, at the average gas flow velocity in cyclone channels were 8, 12 and 16 m/s, the gas flow dynamics dependencies into cyclone were determined.

Experimental Studies Concerning the Semipermeable Membrane Separation Efficiency for 134Cs, 137Cs, 57Co, 58Co, 60Co, 54Mn in Liquid Radioactive Waste I. Treatment of secondary waste from POD decontamination procedure

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Mirela Dulama ◽  
Nicoleta Deneanu ◽  
Cristian Dulama ◽  
Margarit Pavelescu
Keyword(s):  
Membrane Separation ◽  
Separation Efficiency ◽  
Liquid Radioactive Waste ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Suspended Solid ◽  
Process Efficiency ◽  
Active Charcoal ◽  
Precipitation Process ◽  
Pre Treatment

The paper presents the experimental tests concerning the treatment by membrane techniques of radioactive aqueous waste. Solutions, which have been treated by using the bench-scale installation, were radioactive simulated secondary wastes from the decontamination process with modified POD. Generally, an increasing of the retention is observed for most of the contaminants in the reverse osmosis experiments with pre-treatment steps. The main reason for taking a chemical treatment approach was to selectively remove soluble contaminants from the waste. In the optimization part of the precipitation step, several precipitation processes were compared. Based on this comparison, mixed [Fe(CN)6]4-/Al3+/Fe2+ was selected as a precipitation process applicable for precipitation of radionuclides and flocculation of suspended solid. Increased efficiencies for cesium radionuclides removal were obtained in natural zeolite adsorption pre-treatment stages and this was due to the fact that volcanic tuff used has a special affinity for this element. Usually, the addition of powdered active charcoal serves as an advanced purifying method used to remove organic compounds and residual radionuclides; thus by analyzing the experimental data (for POD wastes) one can observe a decreasing of about 50% for cobalt isotopes subsequently to the active charcoal adsorption.. The semipermeable membranes were used, which were prepared by the researchers from the Research Center for Macromolecular Materials and Membranes, Bucharest. The process efficiency was monitored by gamma spectrometry.

Potential Role of Inflammation in Associations between Particulate Matter and Heart Failure

2018 ◽  
Vol 24 (3) ◽  
pp. 341-358 ◽  
Author(s):  
Xiaotong Ji ◽  
Yingying Zhang ◽  
Guangke Li ◽  
Nan Sang
Keyword(s):  
Heart Failure ◽  
Particulate Matter ◽  
Inflammatory Response ◽  
Heart Diseases ◽  
Experimental Studies ◽  
Epidemiological Studies ◽  
Inflammatory Mechanism ◽  
High Concentrations ◽  
Future Work ◽  
The Relationship

Recently, numerous studies have found that particulate matter (PM) exposure is correlated with increased hospitalization and mortality from heart failure (HF). In addition to problems with circulation, HF patients often display high expression of cytokines in the failing heart. Thus, as a recurring heart problem, HF is thought to be a disorder characterized in part by the inflammatory response. In this review, we intend to discuss the relationship between PM exposure and HF that is based on inflammatory mechanism and to provide a comprehensive, updated evaluation of the related studies. Epidemiological studies on PM-induced heart diseases are focused on high concentrations of PM, high pollutant load exposure in winter, or susceptible groups with heart diseases, etc. Furthermore, it appears that the relationship between fine or ultrafine PM and HF is stronger than that between HF and coarse PM. However, fewer studies paid attention to PM components. As for experimental studies, it is worth noting that coarse PM may indirectly promote the inflammatory response in the heart through systematic circulation of cytokines produced primarily in the lungs, while ultrafine PM and its components can enter circulation and further induce inflammation directly in the heart. In terms of PM exposure and enhanced inflammation during the pathogenesis of HF, this article reviews the following mechanisms: hemodynamics, oxidative stress, Toll-like receptors (TLRs) and epigenetic regulation. However, many problems are still unsolved, and future work will be needed to clarify the complex biologic mechanisms and to identify the specific components of PM responsible for adverse effects on heart health.

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