Academic literature on the topic 'Indoor air and particle flow'

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Journal articles on the topic "Indoor air and particle flow"

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Xu, Jiang Rong, Wen Min Tian, Fang Chen, and Yan Liu. "Inhalable Particles Transportation of the Kitchen in Different Ventilation Methods." Applied Mechanics and Materials 71-78 (July 2011): 2158–62. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.2158.

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In order to evaluate the particle exposure level of people indoor, and to improve indoor air quality, research for the particle distribution in residential kitchen is important. In this paper, a residential kitchen is investigated numerically, and the spread and distribution of particles are simulated detailed using the mixture two-phase model. We focused on the particles transportation in different ventilation methods. The four different conditions are designed for simulating the two-phase flow pattern, and the results of particle concentration of different ventilation methods and different particles diameters are obtained. The simulating results are beneficial for increasing the particle removal efficiency and the design of reasonable ventilation methods.
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Hoque, Shamia, and Firoza Omar. "Coupling Computational Fluid Dynamics Simulations and Statistical Moments for Designing Healthy Indoor Spaces." International Journal of Environmental Research and Public Health 16, no. 5 (March 5, 2019): 800. http://dx.doi.org/10.3390/ijerph16050800.

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Cross-contamination between occupants in an indoor space may occur due to transfer of infectious aerosols. Computational fluid dynamics (CFD) provides detailed insight into particle transport in indoor spaces. However, such simulations are site-specific. This study couples CFD with statistical moments and establishes a framework that transitions site-specific results to generating guidelines for designing “healthy” indoor spaces. Eighteen cases were simulated, and three parameters were assessed: inlet/outlet location, air changes per hour, and the presence/absence of desks. Aerosol release due to a simulated “sneeze” in a two-dimensional ventilated space was applied as a test case. Mean, standard deviation, and skewness of the velocity profiles and particle locations gave an overall picture of the spread and movement of the air flow in the domain. A parameter or configuration did not dominate the values, confirming the significance of considering the combined influence of multiple parameters for determining localized air-flow characteristics. Particle clustering occurred more when the inlet was positioned above the outlet. The particle dispersion pattern could be classified into two time zones: “near time”, <60 s, and “far time”, >120 s. Based on dosage, the 18 cases were classified into three groups ranging from worst case scenario to best case scenario.
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Li, Jing, Shao-Wu Yin, Guang-Si Shi, and Li Wang. "Optimization of Indoor Thermal Comfort Parameters with the Adaptive Network-Based Fuzzy Inference System and Particle Swarm Optimization Algorithm." Mathematical Problems in Engineering 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/3075432.

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The goal of this study is to improve thermal comfort and indoor air quality with the adaptive network-based fuzzy inference system (ANFIS) model and improved particle swarm optimization (PSO) algorithm. A method to optimize air conditioning parameters and installation distance is proposed. The methodology is demonstrated through a prototype case, which corresponds to a typical laboratory in colleges and universities. A laboratory model is established, and simulated flow field information is obtained with the CFD software. Subsequently, the ANFIS model is employed instead of the CFD model to predict indoor flow parameters, and the CFD database is utilized to train ANN input-output “metamodels” for the subsequent optimization. With the improved PSO algorithm and the stratified sequence method, the objective functions are optimized. The functions comprise PMV, PPD, and mean age of air. The optimal installation distance is determined with the hemisphere model. Results show that most of the staff obtain a satisfactory degree of thermal comfort and that the proposed method can significantly reduce the cost of building an experimental device. The proposed methodology can be used to determine appropriate air supply parameters and air conditioner installation position for a pleasant and healthy indoor environment.
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Drąg, Marlena. "Model-Based Fiber Diameter Determination Approach to Fine Particulate Matter Fraction (PM2.5) Removal in HVAC Systems." Applied Sciences 11, no. 3 (January 23, 2021): 1014. http://dx.doi.org/10.3390/app11031014.

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Particulate Matter (PM) is a general term to classify air pollutants consisting of airborne particles. The particles vary in composition and size, and the sizes of particles range from 2.5 µm (PM2.5) to 10 µm (PM10). Anthropogenic activity (e.g., industrial processes or fuel/waste combustion) stands as the main emission source of PM. Due to the fact that indoor PM penetrates from the outside to indoor air, Heating, Ventilation, and Air-Conditioning (HVAC) filtration systems may play a significant role in decreasing air pollution indoors. The section of the respiratory tract affected by particulate matter depends on the particle size. The smaller the fraction, the more deeply it can enter into lungs and bronchi, causing a series of health problems. Conventional electret air filters applied in HVAC systems are not able to efficiently remove PM2.5 (e.g., huge gaps between thick fibers and unintentional elimination of electrostatic effects). The electrospinning process allows for the production of fibers of diverse diameters, including ultrathin yarns. The following work presents the axial length scale χχ estimation method for the given conditions and experimental results. According to this approach, it is possible to find out what parameters should be used to produce materials at certain fiber diameters and to capture fine particulate matter fractions (PM2.5). This research refers to poly(acrylonitrile) (PAN) fibers. The most important advantages, limitations, and challenges of the presented methodology are detected and discussed in this work.
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Wang, Kaiyuan, Suyuan Yu, Yingge Wu, and Wei Peng. "Measurements and analysis of adhesive forces for micron particles on common indoor surfaces." Indoor and Built Environment 29, no. 7 (July 15, 2019): 931–41. http://dx.doi.org/10.1177/1420326x19863830.

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Dust particle resuspension from indoor surfaces is an important source of particulate matter in indoor environments. The adhesive force represents the resistance of the particle to resuspension in an air stream and is a key factor in the resuspension process. The present study used an atomic force microscope (AFM) to measure the adhesive forces between three particle samples and four common indoor surfaces including acrylic, marble, epoxy flooring and wood flooring. The effects of different indoor surfaces were investigated using 12 particle–surface combinations. The results show that the average adhesive forces range from 8.2 nN to 448.1 nN for different combinations with the surface roughness being the main factor. The average adhesive force increases with the contact radius and is larger on the wood flooring surface than on the other three surfaces. Then, the resuspension process was simulated using the moment balance method with the measured adhesive forces as the model inputs. The model predictions show that the wood flooring surface has the largest resistance to the air flow entrainment, followed by the epoxy flooring surface, then the marble surface and the least is the acrylic surface.
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Hashimoto, Akinori, and Toshiki Takahashi. "Simulation Study on Indoor Pollen Removal with Variable Exhaust Angle of an Air Purifier." Key Engineering Materials 643 (May 2015): 199–204. http://dx.doi.org/10.4028/www.scientific.net/kem.643.199.

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We calculate pollen grain trajectories in indoor airflow generated by an air purifier to investigate its pollen removal efficiency and effectiveness of the swinging louver at its air outlet. The air purifier has the directional airflow output vent on its top surface, and the elevation angle of the exhaust flow can be changed with time. The turbulent airflow field and particle motion are computed alternately. Since the turbulent calculation requires more computational time than the particle motion simulation, we need to accelerate the computation using graphics processing unit (GPU) to increase simulation research efficiency. As a consequence, the calculation of the indoor turbulent airflow and the particle trajectories on the GPU is 18 times faster than the same simulation on the CPU. It is found that variable exhaust angle enhances pollen removal efficiency by 6.9%. Moreover, it appears that we should swing louver from the upper corner of the ceiling to straight above the air purifier at higher angular velocity than 50 deg/s.
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HASHIMOTO, Akinori, Toshiki TAKAHASHI, Kensaku MATSUMOTO, and Ken-ichi UZAKI. "Simulation of indoor air flow created by an air purifier and particle tracking calculation for pollen grains." Indoor Environment 15, no. 2 (2012): 147–61. http://dx.doi.org/10.7879/siej.15.147.

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Pasquarella, Cesira, Carla Balocco, Maria Eugenia Colucci, Elisa Saccani, Samuel Paroni, Lara Albertini, Pietro Vitali, and Roberto Albertini. "The Influence of Surgical Staff Behavior on Air Quality in a Conventionally Ventilated Operating Theatre during a Simulated Arthroplasty: A Case Study at the University Hospital of Parma." International Journal of Environmental Research and Public Health 17, no. 2 (January 10, 2020): 452. http://dx.doi.org/10.3390/ijerph17020452.

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Surgical staff behavior in operating theatres is one of the factors associated with indoor air quality and surgical site infection risk. The aim of this study was to apply an approach including microbiological, particle, and microclimate parameters during two simulated surgical hip arthroplasties to evaluate the influence of staff behavior on indoor air quality. During the first hip arthroplasty, the surgical team behaved correctly, but in the second operation, behavioral recommendations were not respected. Microbiological contamination was evaluated by active and passive methods. The air velocity, humidity, temperature, and CO2 concentration were also monitored. The highest levels of microbial and particle contamination, as well as the highest variation in the microclimate parameter, were recorded during the surgical operation where the surgical team behaved “incorrectly”. Turbulent air flow ventilation systems appeared more efficient than in the past and very low air microbial contamination was reached when behavior was correct. Therefore, adherence to behavioral recommendations in operating theatres is essential to not undermine the effectiveness of the heating, ventilation, and air conditioning systems and employed resources.
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Xu, Yukun, Xin Wang, Chen Huang, Guangyao Du, and Yujie Zhang. "Assessing the interaction of air from a jet diffuser on a thermal plume in a room using two-dimensional particle image velocimetry." Building Services Engineering Research and Technology 40, no. 6 (January 12, 2019): 669–81. http://dx.doi.org/10.1177/0143624418824798.

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Traditional design of airflow distributions in large spaces does not consider the interference of thermal plumes on jets. In order to quantitatively describe the indoor environment, it is first necessary to quantify how the airflow gets distributed. In this study, a two-dimensional particle image velocimetry (PIV) system for measuring a wide indoor flow field was established. A total of 24 sub-regions (each with a size of 400 mm × 350 mm) were accurately measured in an unmanned room, and the overall cross-sectional flow field was obtained by splicing. Uncertainty analysis proved the rationality of this experimental method. According to the damage extent of the jet structure introduced by the thermal plume, two groups were divided, i.e. Groups A and B. The distribution of velocity fields, trajectories and velocity attenuation of jet centerlines, and velocity magnitude profiles at nozzle and head levels were compared and analyzed in detail. Through this investigation, detailed information of indoor air flow in large spaces can be effectively characterized, which can be useful to help understand the indoor physics and validate CFD models. Practical application: The key to creating a comfortable and healthy indoor thermal environment is the rational design of the airflow distribution. This paper proposes a method for quantitatively describing the airflow distribution in an enclosed space. The equation of the non-dimensional velocity attenuation of jet centerlines is obtained by using advanced technology (PIV), which provides theoretical basis and useful reference for the design of airflow distribution.
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Kim, Ji-Hye, Hee-Gang Kim, and Myoung-Souk Yeo. "Ventilation and Filtration Control Strategy Considering PM2.5, IAQ, and System Energy." Atmosphere 11, no. 11 (October 22, 2020): 1140. http://dx.doi.org/10.3390/atmos11111140.

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Ventilation or filtration control is widely applied to improve indoor particle matter (PM) concentration. Adjusting the ventilation rates to control indoor PM levels can affect the concentration of other indoor pollutants and energy costs, and increasing the filtration flow rate can lower the indoor PM concentration, but also increase the fan energy consumption. In this study, we developed a ventilation and filtration control strategy to determine the optimal control mode and flow rate of the system to meet indoor PM (especially PM2.5) concentration, ensure adequate indoor air quality (IAQ), and minimize fan energy consumption. First, a dynamic model to estimate the indoor PM2.5 generation rate was developed based on the mass balance model and then verified by experiments. Next, the control limit (CL) curve was developed on the basis of the indoor PM2.5 characteristics depending on ventilation and filtration control during various indoor and outdoor PM2.5 conditions (indoor PM2.5 generation rate and outdoor PM2.5 concentration). In addition, an algorithm was proposed to determine the optimal control mode and flow rate of the system. Condition zone control can keep indoor PM2.5 below or as close to the desired target concentration as possible, maintain IAQ within acceptable ranges, and save about 15~70% of fan energy compared with the conventional rule-based control under the case condition.
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Dissertations / Theses on the topic "Indoor air and particle flow"

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Tian, Zhaofeng, and rmit tian@gmail com. "Numerical Modelling of Turbulent Gas-Particle Flow and Its Applications." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080528.150211.

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The aim of this thesis is three-fold: i) to investigate the performance of both the Eulerian-Lagrangian model and the Eulerian-Eulerian model to simulate the turbulent gas-particle flow; ii) to investigate the indoor airflows and contaminant particle flows using the Eulerian-Lagrangian model; iii) to develop and validate particle-wall collision models and a wall roughness model for the Eulerian-Lagrangian model and to utilize these models to investigate the effects of wall roughness on the particle flows. Firstly, the Eulerian-Lagrangian model in the software package FLUENT (FLUENT Inc.) and the Eulerian-Eulerian model in an in-house research code were employed to simulate the gas-particle flows. The validation against the measurement for two-phase flow over backward facing step and in a 90-degree bend revealed that both CFD approaches provide reasonably good prediction for both the gas and particle phases. Then, the Eulerian-Lagrangian model was employed to investigate the indoor airflows and contaminant particle concentration in two geometrically different rooms. For the first room configuration, the performances of three turbulence models for simulating indoor airflow were evaluated and validated against the measured air phase velocity data. All the three turbulence models provided good prediction of the air phase velocity, while the Large Eddy Simulation (LES) model base on the Renormalization Group theory (RNG) provided the best agreement with the measurements. As well, the RNG LES model is able to provide the instantaneous air velocity and turbulence that are required for the evaluation and design of the ventilation system. In the other two-zone ventilated room configuration, contaminant particle concentration decay within the room was simulated and validated against the experimental data using the RNG LES model together with the Lagrangian model. The numerical results revealed that the particle-wall coll ision model has a considerable effect on the particle concentration prediction in the room. This research culminates with the development and implementation of particle-wall collision models and a stochastic wall roughness model in the Eulerian-Lagrangian model. This Eulerian-Lagrangian model was therefore used to simulate the gas-particle flow over an in-line tube bank. The numerical predictions showed that the wall roughness has a considerable effect by altering the rebounding behaviours of the large particles and consequently affecting the particles motion downstream along the in-line tube bank and particle impact frequency on the tubes. Also, the results demonstrated that for the large particles the particle phase velocity fluctuations are not influenced by the gas-phase fluctuations, but are predominantly determined by the particle-wall collision. For small particles, the influence of particle-wall collisions on the particle fluctuations can be neglected. Then, the effects of wall roughness on the gas-particle flow in a two-dimensional 90-degree bend were investigated. It was found that the wa ll roughness considerably altered the rebounding behaviours of particles by significantly reducing the 'particle free zone' and smoothing the particle number density profiles. The particle mean velocities were reduced and the particle fluctuating velocities were increased when taking into consideration the wall roughness, since the wall roughness produced greater randomness in the particle rebound velocities and trajectories.
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Kanaani, Hussein. "Real time detectionof airborne fungal spores and investigations into their dynamics in indoor air." Queensland University of Technology, 2009. http://eprints.qut.edu.au/30350/.

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Concern regarding the health effects of indoor air quality has grown in recent years, due to the increased prevalence of many diseases, as well as the fact that many people now spend most of their time indoors. While numerous studies have reported on the dynamics of aerosols indoors, the dynamics of bioaerosols in indoor environments are still poorly understood and very few studies have focused on fungal spore dynamics in indoor environments. Consequently, this work investigated the dynamics of fungal spores in indoor air, including fungal spore release and deposition, as well as investigating the mechanisms involved in the fungal spore fragmentation process. In relation to the investigation of fungal spore dynamics, it was found that the deposition rates of the bioaerosols (fungal propagules) were in the same range as the deposition rates of nonbiological particles and that they were a function of their aerodynamic diameters. It was also found that fungal particle deposition rates increased with increasing ventilation rates. These results (which are reported for the first time) are important for developing an understanding of the dynamics of fungal spores in the air. In relation to the process of fungal spore fragmentation, important information was generated concerning the airborne dynamics of the spores, as well as the part/s of the fungi which undergo fragmentation. The results obtained from these investigations into the dynamics of fungal propagules in indoor air significantly advance knowledge about the fate of fungal propagules in indoor air, as well as their deposition in the respiratory tract. The need to develop an advanced, real-time method for monitoring bioaerosols has become increasingly important in recent years, particularly as a result of the increased threat from biological weapons and bioterrorism. However, to date, the Ultraviolet Aerodynamic Particle Sizer (UVAPS, Model 3312, TSI, St Paul, MN) is the only commercially available instrument capable of monitoring and measuring viable airborne micro-organisms in real-time. Therefore (for the first time), this work also investigated the ability of the UVAPS to measure and characterise fungal spores in indoor air. The UVAPS was found to be sufficiently sensitive for detecting and measuring fungal propagules. Based on fungal spore size distributions, together with fluorescent percentages and intensities, it was also found to be capable of discriminating between two fungal spore species, under controlled laboratory conditions. In the field, however, it would not be possible to use the UVAPS to differentiate between different fungal spore species because the different micro-organisms present in the air may not only vary in age, but may have also been subjected to different environmental conditions. In addition, while the real-time UVAPS was found to be a good tool for the investigation of fungal particles under controlled conditions, it was not found to be selective for bioaerosols only (as per design specifications). In conclusion, the UVAPS is not recommended for use in the direct measurement of airborne viable bioaerosols in the field, including fungal particles, and further investigations into the nature of the micro-organisms, the UVAPS itself and/or its use in conjunction with other conventional biosamplers, are necessary in order to obtain more realistic results. Overall, the results obtained from this work on airborne fungal particle dynamics will contribute towards improving the detection capabilities of the UVAPS, so that it is capable of selectively monitoring and measuring bioaerosols, for which it was originally designed. This work will assist in finding and/or improving other technologies capable of the real-time monitoring of bioaerosols. The knowledge obtained from this work will also be of benefit in various other bioaerosol applications, such as understanding the transport of bioaerosols indoors.
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Funes-Gallanzi, Marcelo. "Unsteady flow measurements in air using particle image velocimetry." Thesis, University of Warwick, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307299.

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Saxena, Gaurav. "Air flow separation over wind generated waves." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 235 p, 2007. http://proquest.umi.com/pqdweb?did=1251900711&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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He, Congrong. "Airborne Particles in Indoor Residential Environment: Source Contribution, Characteristics, Concentration, and Time Variability." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16017/.

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The understanding of human exposure to indoor particles of all sizes is important to enable exposure control and reduction, but especially for smaller particles since the smaller particles have a higher probability of penetration into the deeper parts of the respiratory tract and also contain higher levels of trace elements and toxins. Due to the limited understanding of the relationship between particle size and the health effects they cause, as well as instrument limitations, the available information on submicrometer (d < 1.0 µm) particles indoors, both in terms of mass and number concentrations, is still relatively limited. This PhD project was conducted as part of the South-East Queensland Air Quality program and Queensland Housing Study aimed at providing a better understanding of ambient particle concentrations within the indoor environment with a focus on exposure assessment and control. This PhD project was designed to investigate comprehensively the sources and sinks of indoor aerosol particles and the relationship between indoor and outdoor aerosol particles, particle and gaseous pollutant, as well as the association between indoor air pollutants and house characteristics by using, analysing and interpreting existing experimental data which were collected before this project commenced, as well as data from additional experiments which were designed and conducted for the purpose of this project. The focus of this research was on submicrometer particles with a diameter between 0.007 - 0.808 µm. The main outcome of this project may be summarised as following: * A comprehensive review of particle concentration levels and size distributions characteristics in the residential and non-industrial workplace environments was conducted. This review included only those studies in which more general trends were investigated, or could be concluded based on information provided in the papers. This review included four parts: 1) outdoor particles and their effect on indoor environments; 2) the relationship between indoor and outdoor concentration levels in the absence of indoor sources for naturally ventilated buildings; 3) indoor sources of particles: contribution to indoor concentration levels and the effect on I/O ratios for naturally ventilated buildings; and 4) indoor/outdoor relationship in mechanically ventilated buildings. * The relationship between indoor and outdoor airborne particles was investigated for sixteen residential houses in Brisbane, Australia, in the absence of operating indoor sources. Comparison of the ratios of indoor to outdoor particle concentrations revealed that while temporary values of the ratio vary in a broad range from 0.2 to 2.5 for both lower and higher ventilation conditions, average values of the ratios were very close to one regardless of ventilation conditions and of particle size range. The ratios were in the range from 0.78 to 1.07 for submicrometer particles, from 0.95 to 1.0 for supermicrometer particles and from 1.01 to 1.08 for PM2.5 fraction. Comparison of the time series of indoor to outdoor particle concentrations showed a clear positive relationship existing for many houses under normal ventilation conditions (estimated to be about and above 2 h-1), but not under minimum ventilation conditions (estimated to be about and below 1 h-1). These results suggest that for normal ventilation conditions and in the absence of operating indoor sources, outdoor particle concentrations could be used to predict instantaneous indoor particle concentrations but not for minium ventilation, unless air exchange rate is known, thus allowing for estimation of the "delay constant". * Diurnal variation of indoor submicrometer particle number and particle mass (approximation of PM2.5) concentrations was investigated in fifteen of the houses. The results show that there were clear diurnal variations in both particle number and approximation of PM2.5 concentrations, for all the investigated houses. The pattern of diurnal variations varied from house to house, however, there was always a close relationship between the concentration and human indoor activities. The average number and mass concentrations during indoor activities were (18.2±3.9)×10³ particles cm-³ and (15.5±7.9) µg m-³ respectively, and under non-activity conditions, (12.4±2.7)x10³ particles cm-³ (11.1±2.6) µg m-³, respectively. In general, there was a poor correlation between mass and number concentrations and the correlation coefficients were highly variable from day to day and from house to house. This implies that conclusions cannot be drawn about either one of the number or mass concentration characteristics of indoor particles, based on measurement of the other. The study also showed that it is unlikely that particle concentrations indoors could be represented by measurements conducted at a fixed monitoring station due to the large impact of indoor and local sources. * Emission characteristics of indoor particle sources in fourteen residential houses were quantified. In addition, characterizations of particles resulting from cooking conducted in an identical way in all the houses were measured. All the events of elevated particle concentrations were linked to indoor activities using house occupants diary entries, and catalogued into 21 different types of indoor activities. This enabled quantification of the effect of indoor sources on indoor particle concentrations as well as quantification of emission rates from the sources. For example, the study found that frying, grilling, stove use, toasting, cooking pizza, smoking, candle vaporizing eucalyptus oil and fan heater use, could elevate the indoor submicrometer particle number concentration levels by more than 5 times, while PM2.5 concentrations could be up to 3, 30 and 90 times higher than the background levels during smoking, frying and grilling, respectively. * Indoor particle deposition rates of size classified particles in the size range from 0.015 to 6 µm were quantified. Particle size distribution resulting from cooking, repeated under two different ventilation conditions in 14 houses, as well as changes to particle size distribution as a function of time, were measured using a scanning mobility particle sizer (SMPS), an aerodynamic particle sizer (APS), and a DustTrak. Deposition rates were determined by regression fitting of the measured size-resolved particle number and PM2.5 concentration decay curves, and accounting for air exchange rate. The measured deposition rates were shown to be particle size dependent and they varied from house to house. The lowest deposition rates were found for particles in the size range from 0.2 to 0.3 µm for both minimum (air exchange rate: 0.61±0.45 h-1) and normal (air exchange rate: 3.00±1.23 h-1) ventilation conditions. The results of statistical analysis indicated that ventilation condition (measured in terms of air exchange rate) was an important factor affecting deposition rates for particles in the size range from 0.08 to 1.0 µm, but not for particles smaller than 0.08 µm or larger than 1.0 µm. Particle coagulation was assessed to be negligible compared to the two other processes of removal: ventilation and deposition. This study of particle deposition rates, the largest conducted so far in terms of the number of residential houses investigated, demonstrated trends in deposition rates comparable with studies previously reported, usually for significantly smaller samples of houses (often only one). However, the results compare better with studies which, similarly to this study, investigated cooking as a source of particles (particle sources investigated in other studies included general activity, cleaning, artificial particles, etc). * Residential indoor and outdoor 48 h average levels of nitrogen dioxide (NO2), 48h indoor submicrometer particle number concentration and the approximation of PM2.5 concentrations were measured simultaneously for fourteen houses. Statistical analyses of the correlation between indoor and outdoor pollutants (NO2 and particles) and the association between house characteristics and indoor pollutants were conducted. The average indoor and outdoor NO2 levels were 13.8 ± 6.3 ppb and 16.7 ± 4.2 ppb, respectively. The indoor/outdoor NO2 concentration ratio ranged from 0.4 to 2.3, with a median value of 0.82. Despite statistically significant correlations between outdoor and fixed site NO2 monitoring station concentrations (p = 0.014, p = 0.008), there was no significant correlation between either indoor and outdoor NO2 concentrations (p = 0.428), or between indoor and fixed site NO2 monitoring station concentrations (p = 0.252, p = 0.465,). However, there was a significant correlation between indoor NO2 concentration and indoor submicrometer aerosol particle number concentrations (p = 0.001), as well as between indoor PM2.5 and outdoor NO2 (p = 0.004). These results imply that the outdoor or fixed site monitoring concentration alone is a poor predictor of indoor NO2 concentration. * Analysis of variance indicated that there was no significant association between indoor PM2.5 and any of the house characteristics investigated (p > 0.05). However, associations between indoor submicrometer particle number concentration and some house characteristics (stove type, water heater type, number of cars and condition of paintwork) were significant at the 5% level. Associations between indoor NO2 and some house characteristics (house age, stove type, heating system, water heater type and floor type) were also significant (p < 0.05). The results of these analyses thus strongly suggest that the gas stove, gas heating system and gas water heater system are main indoor sources of indoor submicrometer particle and NO2 concentrations in the studied residential houses. The significant contributions of this PhD project to the knowledge of indoor particle included: 1) improving an understanding of indoor particles behaviour in residential houses, especially for submicrometer particle; 2) improving an understanding of indoor particle source and indoor particle sink characteristics, as well as their effects on indoor particle concentration levels in residential houses; 3) improving an understanding of the relationship between indoor and outdoor particles, the relationship between particle mass and particle number, correlation between indoor NO2 and indoor particles, as well as association between indoor particle, NO2 and house characteristics.
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Beausoleil-Morrison, Ian David. "The adaptive coupling of heat and air flow modelling within dynamic whole-building simulation." Thesis, University of Strathclyde, 2000. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21137.

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This thesis is concerned with advancing the modelling of indoor air flow and internal surface convection within dynamic whole-building simulation. The path taken is the conflation of computational fluid dynamics (CFD) techniques with dynamic whole-building simulation, with an accurate treatment of the co-dependencies between these modelling domains. Two flow responsive modelling techniques were devised and implemented within the ESP-r simulation program to achieve the research objectives. The adaptive convection algorithm enhances ESP-r's thermal simulation domain by dynamically controlling the simulation of internal surface convection. Empirical methods were extracted from the literature and a new method for characterizing mixed flow convective regimes was created to provide the algorithm with a basis of 28 convection coefficient correlations. Collectively these methods can calculate convection coefficients for most flows of practical interest. Working with this suite of correlations, the algorithm assigns appropriate equations to each internal surface and adapts the selection in response to the room's evolving flow regime. The adaptive conflation controller manages all interactions between the thermal and CFD modelling domains. The controller incorporates the latest turbulence modelling advancements applicable for room air flow simulation and possesses a suite of handshaking and thermal boundary condition treatments. The job of this adaptive conflation controller is to monitor the evolving thermal and air flow conditions in the room and dynamically select an appropriate combination of modelling approaches for the prevailing conditions. The two control schemes implemented to demonstrate the controller make use of a double-pass modelling approach. Each time-step that the thermal domain handshakes with CFD, the adaptive conflation controller performs an investigative simulation to approximate the room's flow and temperature field. Using these estimates, the controller calculates dimensionless groupings to determine the nature of the flow (forced, buoyant, mixed, fully turbulent, weakly turbulent) adjacent to each internal surface. This information is used to select suitable boundary condition treatments for each surface. A second CFD simulation is then performed using the refined modelling approach to more accurately resolve the room's air flow and temperature distribution, and to predict surface convection. In order to protect the thermal domain, a two-stage screening process is used to assess (and where necessary reject) the CFD-predicted surface convection estimates. These adaptive modelling techniques advance the modelling of indoor air flow and internal surface convection within whole-building simulation.
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Doucet, Daniel Joseph. "Measurements of Air Flow Velocities in Microchannels Using Particle Image Velocimetry." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1333675768.

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Segal, Rebecca Anne. "Patterns of air flow and particle deposition in the diseased human lung." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010702-165013.

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SEGAL, REBECCA ANNE. Patterns of air flow and particle depositionin the diseased human lung. (Under the direction of Michael Shearer.)In this work, we investigate particle deposition and air flow in thehuman lung. In particular we are interested in how the motion ofparticulate matter and air is affected by the presence of lungdisease. Patients with compromised lung function are more sensitiveto air pollution; understanding the extent of that sensitivity canlead to more effective air quality standards. Also, understanding ofair flow andparticle trajectories could lead to the development of better aerosoldrugs to treat the lung diseases.We focus our efforts on twodiseases: chronic obstructive pulmonary disease (COPD) and bronchialtumors. Because COPD affects the majority of airways in a patientwith the disease, we are able to take a more global approach toanalyzing the effects of the disease. Using a FORTRAN codewhich computes total deposition in the lung over the course of onebreath, we modified the pre-existing code to account forthe difference between healthy subjects and patients with COPD. Usingthe model, itwas possible to isolate the different disease components of COPD andsimulate their effects separately. It was determined thatthe chronic bronchitis component of COPD was responsible for the increaseddeposition seen in COPD patients.While COPD affects the whole lung, tumors tend to belocalized to one or several airways. This led us to investigate theeffects of bronchial tumors in detail within these individualairways. Using a computational fluid dynamics package, FIDAP, wedefined a Weibel type branching network of airways.In particular, we modeled theairways of a four-year-old child.In the work with the tumors, we ran numerous simulations with variousinitial velocities and tumor locations. It was determined that tumorslocated on the carinal ridge had the dominant effect on the flow. Athigher initial velocities, areas of circulation developed downstreamfrom the tumors. Extensive simulations were run with a 2-D model. Theresults from the 2-D model were then compared with some initial 3-Dsimulations.In the development of the FIDAP model, we avoided thecomplications of flow past the larynx, by limiting the model togenerations 2-5 of the Weibel lung. We developed a realistic inletvelocity profile to be used as the input into the model. The skewednature ofthis inlet profile led to thequestion of boundary layer development and the determination of theentrance length needed to achieve fully developed parabolicflow. Simple scale analysis of the Navier-Stokes equations did notcapture the results we were seeing with the CFD simulations.We turned to a more quantitative, energy correctionanalysis to determine the theoretical entrance length.In conclusion, the presence of disease in the lunghas a large effect both on global deposition patterns and on localizedairflow patterns. This indicates the need for different protocolsregarding susceptibility of people to airborne pollutants that take intoaccount lung disease. It also suggests that treatment should accountfor changes in airflow in the diseased lung.

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Henning, James C. "MEASUREMENT OF AIR FLOW VELOCITIES IN MICROSIZED IONIC WIND PUMPS USING PARTICLE IMAGE VELOCEMITRY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1365424846.

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Johnson, Neil G. "Vision-Assisted Control of a Hovering Air Vehicle in an Indoor Setting." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2430.pdf.

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Books on the topic "Indoor air and particle flow"

1

The measurement and simulation of indoor air flow. Eindhoven: University of Eindhoven, 1998.

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Funes-Gallanzi, Marcelo. Unsteady flow measurements in air using particle image velocimetry. [s.l.]: typescript, 1994.

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Dandan, Zhu, and American Society of Heating, Refrigerating and Air-Conditioning Engineers., eds. Designer's guide to ceiling-based air diffusion. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2002.

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Walton, George N. Estimating interroom contaminant movements. Gaithersburg, MD: U.S. Dept. of Commerce, National Bureau of Standards, 1985.

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Cunningham, William L. Evaluation of ground-water flow by particle tracking, Wright-Patterson Air Force Base, Ohio. Columbus, Ohio: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.

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L, Cunningham William. Evaluation of ground-water flow by particle tracking, Wright-Patterson Air Force Base, Ohio. Columbus, Ohio: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.

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L, Cunningham William. Evaluation of ground-water flow by particle tracking, Wright-Patterson Air Force Base, Ohio. Columbus, Ohio: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.

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Cunningham, William L. Evaluation of ground-water flow by particle tracking, Wright-Patterson Air Force Base, Ohio. Columbus, Ohio: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.

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United States. National Aeronautics and Space Administration., ed. Particle displacement tracking applied to air flows. [Washington, DC]: National Aeronautics and Space Administration, 1991.

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J, Nabinger Steven, and National Institute of Standards and Technology (U.S.), eds. Measurement and simulation of the IAQ impact of particle air cleaners in a single-zone building. Gaithersburg, Md: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 2000.

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Book chapters on the topic "Indoor air and particle flow"

1

Kentner, M., and D. Weltle. "Are There Any Impairments of Maximal Expiratory Flow-Volume Curves by Passive Smoking?" In Indoor Air Quality, 153–66. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-83904-7_18.

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Xu, Zhonglin. "Movement of Indoor Fine Particle." In Fundamentals of Air Cleaning Technology and Its Application in Cleanrooms, 289–338. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-39374-7_6.

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Wallace, Lance, and Philip Hopke. "Measuring Particle Concentration and Compositions in Indoor Air." In Handbook of Indoor Air Quality, 1–55. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-10-5155-5_19-1.

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Torii, Shuichi, and Wen-Jei Yang. "Rising Bubble Behavior in Air-Particle Injection by Means of Image Processing." In Flow Visualization VI, 399–403. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-84824-7_70.

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Kähler, C. J., B. Sammler, and J. Kompenhans. "Generation and Control of Tracer Particles for Optical Flow Investigations in Air." In Particle Image Velocimetry: Recent Improvements, 417–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-642-18795-7_30.

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Pratap, Rajiv, Ramesh Rayudu, and Manfred Plagmann. "Modelling of Air Flow Analysis for Residential Homes Using Particle Image Velocimetry." In IFIP Advances in Information and Communication Technology, 293–302. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15994-2_29.

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Ferrero, E., F. Desiato, G. Brusasca, D. Anfossi, G. Tinarelli, M. G. Morselli, S. Finardi, and D. Sacchetti. "Intercomparison of 3-D Flow and Particle Models with TRANSALP 1989 Meteorological and Tracer Data." In Air Pollution Modeling and Its Application XI, 559–67. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-5841-5_58.

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Settles, G. S., and G. G. Via. "Measurement and Control of Particle-Bearing Air Currents in a Vertical Laminar Flow Clean Room." In Particles in Gases and Liquids 1, 185–94. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4613-0793-8_12.

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Dragojlovic, Dusica, Nathan Ricks, Sylvia Verbanck, Chris Lacor, and Ghader Ghorbaniasl. "Numerical Study of the Air Flow and Aerosol Particle Transport in a Model of the Human Respiratory Tract." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 123–29. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-60387-2_12.

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"Ideal Flow." In Indoor Air Quality Engineering, 517–80. CRC Press, 2003. http://dx.doi.org/10.1201/9780203911693.ch7.

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Conference papers on the topic "Indoor air and particle flow"

1

Goldasteh, Iman, Goodarz Ahmadi, and Andrea Ferro. "Effect of Air Flow on Dust Particles Resuspension From Common Flooring." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30596.

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Particle resuspension from flooring in connection with increased indoor air pollution was studied. Earlier efforts hypothesized that during the gait cycle, high speed airflow is generated at the floor level that would lead to particle resuspension. The details of the mechanism of the particle resuspension, however, are not well understood. Earlier models were mainly developed for spherical particle detachment from smooth surfaces, but in reality, dust particles are irregular in shape and have a wide size distribution. The resuspension of dust particles thus depends on their shape and size and the nature of their contact with the surface. In this work, a wind tunnel study of dust particle resuspension from common flooring was performed and the critical air velocities for particle detachment were measured. The main goal of the present experimental work is to understand the main mechanism of dust particle resuspension under real conditions by systematically investigating a range of airflow speeds. The other goal of the study is to provide information on the role of the airflow on dust particle detachment from common floorings.
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Javadpour, Sina, Fereidoon Delfanian, and Khaled Saadeddin. "Numerical Simulations of Airborne Particle Removal Rates for Air-Ventilated Spaces of Different Obstacle Setups." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67004.

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As a result of industrialization, human activities and consequently the time spent in indoor spaces has significantly increased. As airborne particles, especially those of relatively small sizes (less than 2 μm), can easily enter human respiratory tract and cross the thin air-blood barrier inside the lungs, necessary measures need to be taken to minimize exposure to these particles. In this study numerical simulations were done by coupling the “Laminar” and “Turbulent Flow” and the “Particle Tracing for Fluid Flow” interfaces in COMSOL Multiphysics to investigate the effects of obstacle setup on air flow profile and particle removal rate in a confined space of an air-ventilated office using 3D models. Particle tracing for fluid flow was used with a Newtonian formulation to simulate and trace particles with diameter of 0.5 μm and density of 1086 kg/m3. A total of 100,000 particles were simulated to reduce the uncertainty in particle concentration calculations and also to yield statistically more accurate results. Simulations were done for a control model with no obstacles, and 3 other models of different obstacle setups in a cubic room of 2.5 m * 4 m * 1 m with the same inlet and outlet configurations and a maximum interval of 180 minutes (3 hours). All cases had a monodisperse particle distribution, where particles were released transiently and evenly distributed through the entire space at the initial time step (t = 0 min). All models reached a steady-state stage after 180 minutes, with the remaining particles circulating and trapped. Analyzing the results revealed that a positive correlation exists between path-length and particle removal rate. Thus, it was concluded that an obstacle orientation and setup leading to increased flow path-length would greatly enhance the particle removal rate and pollutant dilution. Also, regions of recirculation and stagnation proved to have a negative impact on particle removal by trapping the particles and hence should be avoided in obstacle configuration.
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Ahmadi, Goodarz. "Overview of Particle Transport and Deposition in Environmental and Industrial Applications." In ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72144.

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Overview of particle transport and deposition in flows in environmental and industrial applications was presented. Aerosol transport including particle deposition, removal and re-entrainment in turbulent flows were discussed. The numerical simulation airflow through the Reynolds averaged Navier-Stokes equation was described. The approximate stochastic models for simulation of instantaneous flow were discussed. The Lagrangian particle equation of motion was presented. It was shown that the particle deposition and removal processes in turbulent flows are strongly affected by the near wall flow structures. Wind tunnel studies of particle transport and deposition were also discussed. Examples of computational modeling of gas-solid flows in indoor and out door air were described. It was shown that computational modeling was an efficient tool for studying alternative scenarios. A simulation procedure for pollutant transport through human upper airways was discussed and sample results were presented.
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Goldasteh, Iman, Goodarz Ahmadi, and Andrea Ferro. "Monte Carlo Simulations of Micro-Particle Detachment and Resuspension From Surfaces in Turbulent Flows." In ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72148.

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Micro-particle adhesion, detachment and resuspension from surfaces have attracted considerable attention due to their numerous applications in semiconductor, xerographic, and pharmaceutical industries, and, more recently, in understanding indoor air quality. However, most earlier studies have focused on idealized spherical particles and smooth surfaces, and the effects of particle irregularities and surface roughness on the rate of particle removal and resuspension are not well understood. In this work, a Monte Carlo simulation of particle resuspension from a surface under turbulent flow conditions was developed and resuspension of nearly spherical and irregular shaped particles with rough surfaces from substrates under turbulent flow condition was studied. Following our earlier approach, compact irregular shaped particles were modeled as spherical particles with a number of hemispherical bumps. It was assumed that the bump surfaces also have fine roughness. The extended Johnson-Kendall-Roberts (JKR) adhesion theory for rough surfaces was used to model the particle adhesion and detachment. A number of assumptions were made to apply the model. It was assumed that the particles have a Gaussian size distribution. The number of bumps of the irregular particles and surface roughness values of particle are assumed to be random, respectively, with Poisson and log-normal distributions. For particle detachment from the surface, the theory of critical moment was used. The effects of particle size, turbulent flow, particle irregularity and surface roughness on particle detachment and resuspension were studied for different cases. The Monte Carlo model predictions show probabilistic distributions of the particle resuspension. The simulation results are compared with the available experimental data and good agreement was found. The study provided information on the random nature of particle resuspension due to the randomness in the airflow, particle size distribution and surface roughness.
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Zheng, Z. C., Z. Wei, and J. S. Bennett. "Investigation of Exhaust Conditions on Influencing Contaminant Transport for Indoor Environments." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-22089.

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Indoor air quality is an important issue involved in a wide variety of industrial applications. In an indoor environment, different types of contaminants exist and have an inevitable potential to cause health problems for human beings and animals. In this study, the focus is on the contaminant contained in painting materials. While painting materials being sprayed to solid surfaces, pollutant plumes are formed near the painting area, which may enclose the body parts of the sprayers. Severe health problems are possible to occur if a significant amount of painting materials settles on the face of workers. By applying exhaust conditions (i.e. exhaust fan with outlet velocity), the flow convection in the room can be enhanced, which may alleviate the contaminant level on the human body. In such a case, the choice of exhaust condition becomes crucial. With the aid of computational fluid dynamics, an optimal exhaust condition can be determined. To simulate this kind of fluid/solid-particle multiphase flow, the current study employs a pure Eulerian or Euler-Euler type model. In the Euler-Euler approach, the properties of the contaminant particles are assumed to be continuous as those of fluids and all phases are computed in the Eulerian framework. Since the exhaust speed is moderately low and fully turbulent flow is not guaranteed in the room, the RNG k-e model is used as a low Reynolds number turbulent model. The current paper firstly investigated the scenario of sprayer self-contamination. Then, inter-contaminations among different workers will be studied.
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Janajreh, Isam, Muhammad Sajjad, MD Islam, and Lina Janajreh. "Numerical Simulation of Indoor Human Sneezing." In ASME 2021 Heat Transfer Summer Conference collocated with the ASME 2021 15th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/ht2021-64043.

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Abstract Transient numerical simulations have been carried out to mimic and analyse the transmission of various species resulting from human sneezing. The extent of the spread of sneezed air and associated droplets is also investigated based on various parameters. A 2D geometry of the human face is considered that captures the true topology and the outlet characteristics of the exhaled air mixture. Numerous parameters are required to be considered to capture the out-coming mixture trajectory and to track its concentration evolution as it enters and entrains with the surrounding air. These parameters include the velocity of the exhaled air mixture, the extent of mouth opening, the distribution of the mixture fraction, and its mist content. A multi-species Eulerian flow with discrete phase Lagrangian particles is considered. The results include the spatial and temporal distributions of the species and their velocity contour plots. Specifically, the concentration of the exhaled species is captured both spatially and temporally at several hypothetical stations within the computational domain, and away from the source to substantiate/refute the current recommended social distance parameter.
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Zhuang, Xinwei, and Xiuling Wang. "Environment Analysis Near a Highway Using Computational Fluid Dynamics." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38717.

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Air pollution has been proven as a significant risk factor for multiple health conditions. A major portion of urban air pollution is attributed to vehicle emissions. In this study, a high school which is close to an interstate highway is numerical simulated to estimate the impact of traffic emissions on air quality. Two probability density functions, Weibull distribution and Rayleigh distribution, were used in wind data statistical analysis. A numerical method was used to estimate the wind speed at study site based on the wind data in meteorology stations. Both indoor and outdoor environment were simulated using computational fluid dynamics (CFD). The airflow and the dispersion of particulate air pollutants emitted from the highways surrounding the high school building were analyzed. The wind flow was simulated using Reynolds-Averaged Navier Stokes (RANS) model. The particulate matters are tracked using Lagrangian model. For the indoor simulation, the standard k-ε model is employed to model the air-phase turbulence. Discrete phase model (DPM) and Eulerian multiphase model were utilized for the particle phase, respectively. The comparison shows that the Lagrangian approach has better agreement since the dispersed-phase volume fractions are less than 10%.
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Octau, Charlene, Marc Lippert, Anthony Graziani, Michel Watremez, Laurent Keirsbulck, Laurent Dubar, and Talib Dbouk. "Particles Transport in Railway Braking Systems: An Experimental and Numerical Investigation." In ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69126.

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There has been a growing public health issue concerning the regulation of indoor air quality (IAQ) and the human exposure to particulate matter (PM). Today, this exposure is a major worldwide concern because ambient PM concentrations in many cities exceeded the limits set by the European air quality directive. Underground airborne particles are mainly generated by the mechanical abrasion of rail tracks, wheels and brake pads produced by urban railways transportation. For that reason, understanding the transport mechanism of particles with various size distribution is essential and crucial for understanding and accurately predicting the behavior of the main high particle concentration areas. In this framework, a simple case of particles emission inside a viscous flow in a channel has been investigated both experimentally and numerically. The suspended particles used experimentally are molybdenum solid particles with a broad size distribution (in diameter) from 1 to 80 μm (size similar to cases such as in braking systems). The experimental tests are conducted for a flow in a channel at a horizontal steady inflow velocity of uf = 0.15m/s. The solid particles are injected transversely to the horizontal bottom wall with an injection steady velocity of ui = 0.95m/s. Measurements and analysis are carried out using shadowscopy technique to determine the particles concentration fields. Finally, experimental results are compared to numerical ones predicted by a continuum computational fluid dynamics (CFD) approach using the SBM (Suspension Balance Model) implemented in “OPENFOAM” (via the Finite Volume Method).
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Ebrahimi, Khosrow, Zhongquan C. Zheng, and Mohammad H. Hosni. "Simulation of the Turbulent Dispersion of 10 Micron Particles in a Generic Half-Cabin Model." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64183.

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Study of particle dispersion in ventilated indoor environments is a very useful and effective way to understand the mechanism for disease transmission in an enclosed environment. In this investigation, a computational approach is adopted in order to gain more knowledge about the transport of particulate materials in a simplified half cabin model of a Boeing 767. The simulations are performed using a commercial Computational Fluid Dynamics (CFD) software and are validated through comparing the predictions with the corresponding experimental measurements. The Lagrange-Euler approach is invoked in the simulations. In this approach, while the air is considered as the continuous first phase, the particles are treated as the discrete second phase. By solving the particles equation of motion, the trajectory of particles is computed. The discrete phase equation of motion is coupled with the continuous phase governing equations through the calculation of drag and buoyancy forces acting on particles. The continuous phase flow is turbulent and Reynolds Averaged Navier Stokes (RANS) is employed in the calculation of velocity field. A complete study on grid dependence of RANS simulation is performed through a controllable local mesh refinement scheme. The grid dependence study shows that using unstructured grid with tetrahedral and hybrid elements in the refinement region are more efficient than using structured grid with hexahedral elements. The effect of turbulence on particle dispersion is taken into account by using a stochastic tracking method (random walk model). Through the comparison of computational predictions with corresponding experimental measurements the capability of Discrete Phase Model (DPM) in predicting the behavior of particles is studied.
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Tavakoli, Behtash, and Goodarz Ahmadi. "Modeling Wind Flow and Particulate Pollutant Dispersion Around a Realistic Model of a Building Using Large-Eddy Simulation." In ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72362.

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Urban air pollution has been of concern due to its adverse effect on human health. A major portion of urban air pollution is attributed to vehicle emissions. Center of Excellence (CoE) Building was built in Syracuse NY at the intersection of two major highways. The building is fully instrumented for assessing outdoor and indoor air pollutions. In this study the airflow and the dispersion of particulate air pollutants emitted from the highways surrounding the CoE building were analyzed. The wind flow around the model of the CoE building was first simulated using the RANS model. Comparison of the numerical simulations with the available PIV experimental data showed that the RANS turbulence model was not able to capture all features of the flow field due to the complexity of the building’s geometry. While the pressure field on the walls of the building model matched with those measured by the pressure taps, some aspects of the airflow velocity profile were not in agreement with the PIV data. The computational modeling of the wind flow around the building was then performed using the Large-Eddy Simulation (LES) approach. The mean velocity magnitude predicted by the LES showed good agreement with the experimental PIV measurements. The simulated flow field was used to predict the dispersion of the particulate pollutant around the building and the deposition fraction of particles on the walls of the building is studied.
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Reports on the topic "Indoor air and particle flow"

1

Hugh I. Henderson, Jensen Zhang, James B. Cummings, and Terry Brennan. Mitigating the Impacts of Uncontrolled Air Flow on Indoor Environmental Quality and Energy Demand in Non-Residential Buildings. Office of Scientific and Technical Information (OSTI), July 2006. http://dx.doi.org/10.2172/924486.

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Kwon, Jaymin, Yushin Ahn, and Steve Chung. Spatio-Temporal Analysis of the Roadside Transportation Related Air Quality (STARTRAQ) and Neighborhood Characterization. Mineta Transportation Institute, August 2021. http://dx.doi.org/10.31979/mti.2021.2010.

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To promote active transportation modes (such as bike ride and walking), and to create safer communities for easier access to transit, it is essential to provide consolidated data-driven transportation information to the public. The relevant and timely information from data facilitates the improvement of decision-making processes for the establishment of public policy and urban planning for sustainable growth, and for promoting public health in the region. For the characterization of the spatial variation of transportation-emitted air pollution in the Fresno/Clovis neighborhood in California, various species of particulate matters emitted from traffic sources were measured using real-time monitors and GPS loggers at over 100 neighborhood walking routes within 58 census tracts from the previous research, Children’s Health to Air Pollution Study - San Joaquin Valley (CHAPS-SJV). Roadside air pollution data show that PM2.5, black carbon, and PAHs were significantly elevated in the neighborhood walking air samples compared to indoor air or the ambient monitoring station in the Central Fresno area due to the immediate source proximity. The simultaneous parallel measurements in two neighborhoods which are distinctively different areas (High diesel High poverty vs. Low diesel Low poverty) showed that the higher pollution levels were observed when more frequent vehicular activities were occurring around the neighborhoods. Elevated PM2.5 concentrations near the roadways were evident with a high volume of traffic and in regions with more unpaved areas. Neighborhood walking air samples were influenced by immediate roadway traffic conditions, such as encounters with diesel trucks, approaching in close proximity to freeways and/or busy roadways, passing cigarette smokers, and gardening activity. The elevated black carbon concentrations occur near the highway corridors and regions with high diesel traffic and high industry. This project provides consolidated data-driven transportation information to the public including: 1. Transportation-related particle pollution data 2. Spatial analyses of geocoded vehicle emissions 3. Neighborhood characterization for the built environment such as cities, buildings, roads, parks, walkways, etc.
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Evaluation of ground-water flow by particle tracking, Wright-Patterson Air Force Base, Ohio. US Geological Survey, 1994. http://dx.doi.org/10.3133/wri944243.

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