Дисертації з теми "Gas solid interaction"
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Tian, Jian Atwood J. L. "Molecular organic solids for gas adsorption and solid-gas interaction." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6882.
Повний текст джерелаKHAN, BILAL ALAM. "Measurement methods of Gas-Solid Interactions." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2942142.
Повний текст джерелаAkizuki, Makoto. "Gas Cluster Ion-Solid Surface Interaction and Thin Film Formation." Kyoto University, 1999. http://hdl.handle.net/2433/181783.
Повний текст джерелаBrancher, Ricardo. "Experimental and numerical analysis of interaction between gas and solid surface." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0677.
Повний текст джерелаThis thesis is devoted to the experimental and numerical study of the interaction between gas and solid surface. Rarefied gas flows through a rectangular microchannel under both isothermal and non-isothermal conditions were experimentally evaluated. The tangential momentum accommodation coefficient for PEEK (Poly Ether Ether Ketone) material associated to five gases (helium, neon, nitrogen, argon, krypton) was extracted from both pressure and temperature gradient driven flows. Additionally, steady one-dimensional flows of a polyatomic gas in the presence of an adsorbing-desorbing surface kept at constant and uniform temperature are simulated by solving numerically the Boltzmann kinetic equation by the Direct Simulation Monte Carlo (DSMC) method. It is considered the flow of gas between two planar and infinite surfaces,where only one surface is able to adsorb and desorb molecules, while the other one is impermeable. Finally, experimental and numerical investigation were performed to analyze the BTEX (benzene, toluene,ethylbenzene and xylenes) species separation inside a chromatographic column. From calibrating the constants of adsorption and desorption, the retention time of each species can be predicted for different operating conditions using the numerical code developed
Qin, Tong. "Numerical Simulations of Interactions of Solid Particles and Deformable Gas Bubbles in Viscous Liquids." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/19225.
Повний текст джерелаbubbles in viscous liquids is very important in many applications,
especially in mining and chemical industries. These interactions
involve liquid-solid-air multiphase flows and an
arbitrary-Lagrangian-Eulerican (ALE) approach is used for the direct
numerical simulations. In the system of rigid particles and
deformable gas bubbles suspended in viscous liquids, the
Navier-Stokes equations coupled with the equations of motion of the
particles and deformable bubbles are solved in a finite-element
framework. A moving, unstructured, triangular mesh tracks the
deformation of the bubble and free surface with adaptive refinement.
In this dissertation, we study four problems. In the first three
problems the flow is assumed to be axisymmetric and two dimensional
(2D) in the fourth problem.
Firstly, we study the interaction between a rising deformable bubble
and a solid wall in highly viscous liquids. The mechanism of the
bubble deformation as it interacts with the wall is described in
terms of two nondimensional groups, namely the Morton number (Mo)
and Bond number (Bo). The film drainage process is also
considered. It is found that three modes of bubble-rigid wall
interaction exist as Bo changes at a moderate Mo.
The first mode prevails at small Bo where the bubble deformation
is small. For this mode, the bubble is
hard to break up and will bounce back and eventually attach
to the rigid wall. In the second mode, the bubble may break up after
it collides with the rigid wall, which is determined by the film
drainage. In the third mode, which prevails at high Bo, the bubble
breaks up due to the bottom surface catches up the top surface
during the interaction.
Secondly, we simulate the interaction between a rigid particle and a
free surface. In order to isolate the effects of viscous drag and
particle inertia, the gravitational force is neglected and the
particle gains its impact velocity by an external accelerating
force. The process of a rigid particle impacting a free surface and
then rebounding is simulated. Simplified theoretical models are
provided to illustrate the relationship between the particle
velocity and the time variation of film thickness between the
particle and free surface. Two film thicknesses are defined. The
first is the thickness achieved when the particle reaches its
highest position. The second is the thickness when the particle
falls to its lowest position. The smaller of these two thicknesses
is termed the minimum film thickness and its variation with the
impact velocity has been determined. We find that the interactions
between the free surface and rigid particle can be divided into
three regimes according to the trend of the first film thickness.
The three regimes are viscous regime, inertial regime and jetting
regime. In viscous regime, the first film thickness decreases as the
impact velocity increases. Then it rises slightly in the inertial
regime because the effect of liquid inertia becomes larger as the
impact velocity increases. Finally, the film thickness decreases
again due to Plateau-Rayleigh instability in the jetting regime.
We also find that the minimum film thickness corresponds to an
impact velocity on the demarcation point between the viscous and
inertial regimes. This fact is caused by the balance of viscous
drag, surface deformation and liquid inertia.
Thirdly, we consider the interaction between a rigid particle and a
deformable bubble. Two typical cases are simulated: (1) Collision of
a rigid particle with a gas bubble in water in the absence of
gravity, and (2) Collision of a buoyancy-driven rising bubble with a
falling particle in highly viscous liquids. We also compare our
simulation results with available experimental data. Good agreement
is obtained for the force on the particle and the shape of the
bubble.
Finally, we investigated the collisions of groups of bubbles and
particles in two dimensions. A preliminary example of the oblique
collision between a single particle and a single bubble is conducted
by giving the particle a constant acceleration. Then, to investigate
the possibility of particles attaching to bubbles, the interactions
between a group of 22 particles and rising bubbles are studied. Due
to the fluid motion, the particles involved in central collisions
with bubbles have higher possibilities to attach to the bubble.
Ph. D.
Hackett, Gregory A. "Interaction of nickel-based SOFC anodes with trace contaminants from coal-derived synthesis gas." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10728.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains xii, 122 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 115-122).
Mohammad, Hasan Abid Urf Turabe Ali. "Ammonia gas adsorption on metal oxide nanoparticles." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13094.
Повний текст джерелаDepartment of Mechanical and Nuclear Engineering
Steven J. Eckels
NanoActiveTM metal oxide particles have the ability to destructively adsorb organophosphorus compounds and chlorocarbons. These nanomaterials with unique surface morphologies are subjected to separate, low concentrations of gaseous ammonia in air. NanoActiveTM materials based on magnesium oxide have large specific surface areas and defective sites that enhance surface reactivity and consequently improved adsorptivity. In gas contaminant removal by adsorption, presence of vast specific surface area is essential for effective gas-solid interaction to take place. This is also the case in many industrial and chemical applications such as purification of gases, separation and recovery of gases, catalysis etc,. Typically carbonaceous compounds are utilized and engineered in toxic gas control systems. The purpose of this study was to compare NanoActiveTM materials with carbon based compounds in the effectivity of toxic gas adsorption at low concentrations. A test facility was designed to investigate the adsorption properties of novel materials such as adorption capacity and adsorption rate. Adsorption capacity along with adsorption kinetics is a function of properties of the adsorbent and the adsorbate as well as experimental conditions. Nanomaterials were placed on a silica matrix and tested with increasing flow rates. Electrochemical sensing devices were placed at inlet and outlet of the facility to monitor real time continuous concentration profiles. Breakthrough curves were obtained from the packed bed column experiments and saturation limits of adsorbents were measured. Adsorption rates were obtained from the breakthrough curves using modified Wheeler-Jonas equation. The NanoActiveTM materials adsorbed ammonia though to a lesser extent than the Norit® compounds. This study also included measurement of pressure drop in packed beds. This information is useful in estimating energy losses in packed bed reactors. Brauner Emmet Teller tests were carried out for the calculation of surface area, pore volume and pore size of materials. These calculations suggest surface area alone had no notable influence on adsorption capacity and adsorption rates. This lead to the conclusion that adsorption was insignificant cause of absence of functional groups with affinity towards ammonia. In brief, adsorption of ammonia is possible on NanoActiveTM materials. However functional groups such as oxy-flouro compounds should be doped with novel materials to enhance the surface interactions.
Niaki, Seyed Reza Amini. "Effects of inter particle friction on the meso-scale hydrodynamics of dense gas-solid fluidized flows." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18147/tde-10122018-165927/.
Повний текст джерелаReatores de leito fluidizado de escoamento gás-sólido são largamente utilizados nas indústrias química e de energia, e o seu projeto e escalonamento são virtualmente empíricos, extremamente caros e demorados. Este cenário tem motivado o desenvolvimento de ferramentas teóricas alternativas, e a modelagem de dois fluidos, onde gás e particulado são ambos tratados com fases contínuas interpenetrantes, tem surgido como uma aproximação muito promissora. Devido aos grandes domínios a serem resolvidos em reatores de leito fluidizado de escala real, apenas aproximações de modelagem filtradas são viáveis, e modelos de fechamento tornam-se necessários para recuperar efeitos sub-malha que são filtrados pelas malhas numéricas grosseiras que são impostas devido as limitações computacionais. Estes modelos de fechamento, que em formulações hidrodinâmicas respondem principalmente por trocas de momentum filtradas entre fases e tensões filtradas e residuais nas fases, podem ser obtidos de resultados de simulações altamente resolvidas (SAR) realizadas em domínios de dimensões reduzidas sob malhas numéricas refinadas. Uma aproximação largamente praticada consiste na aplicação de modelagem de dois fluidos sob fechamentos definidos na micro-escala, genericamente conhecida como modelagem microscópica de dois fluidos. Esta aproximação inclui fechamentos microscópicos para tensões da fase sólida obtidos da teoria cinética dos escoamentos granulares (TCEG), que considera apenas efeitos cinéticos-colisionais, e é adequada para escoamentos diluídos. Por outro lado, a TCEG convencional não leva em conta efeitos de fricção interpartículas, e sua aplicação para condições densas de escoamento é bastante questionável. Neste trabalho aplica-se uma versão modificada da TCEG disponível na literatura que também leva em conta fricção interpartículas, e simulações altamente resolvidas são realizadas para condições de escoamentos densos visando avaliar os efeitos da fricção sobre os parâmetros filtrados relevantes (coeficiente de arrasto efetivo, tensões filtradas e residuais). Considera-se faixas de frações volumétricas de sólido e números de Reynolds do gás médios no domínio (condições de macro-escala) abrangendo escoamentos gás-sólido fluidizados densos desde suspensões até transporte pneumático. O código aberto MFIX é utilizado em todas as simulações, que foram executadas sobre domínios periódicos 2D para um único particulado monodisperso. Os resultados das SAR (i.e., campos de escoamento de meso-escala) foram filtrados sobre regiões compatíveis com tamanhos de malha praticados em simulações de grandes escalas, e os parâmetros filtrados relevantes de interesse são calculados e classificados por faixas de outros parâmetros filtrados tomados como variáveis independentes (fração volumétrica de sólido filtrada, velocidade de deslizamento filtrada, e energia cinética das flutuações de velocidade da fase sólida filtrada, que são referidos como marcadores). Os resultados mostram que os parâmetros filtrados relevantes de interesse são bem correlacionados com todos os marcadores, e também com todas as condições de macro-escala impostas. Por outro lado, a fricção interpartículas não mostrou efeitos significativos sobre qualquer parâmetro filtrado. Reconhece-se que este aspecto claramente requer investigações adicionais, notadamente com respeito à adequação dos marcadores que foram considerados para classificação dos resultados filtrados. O trabalho corrente é posto como uma contribuição para o desenvolvimento futuro de modelos de fechamento mais acurados para simulações de grandes escalas de escoamentos gás-sólido fluidizados.
Lazarevic, David Andrew. "In-situ Removal of Hydrogen Sulphide from Landfill Gas : Arising from the Interaction between Municipal Solid Waste and Sulphide Mine Environments within Bioreactor Conditions." Thesis, KTH, Industriell ekologi, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32770.
Повний текст джерелаwww.ima.kth.se
Tóth, Balázs. "Two-phase flow investigation in a cold-gas solid rocket motor model through the study of the slag accumulation process." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210575.
Повний текст джерелаThe first stage of spacecrafts (e.g. Ariane 5, Vega, Shuttle) generally consists of large solid propellant rocket motors (SRM), which often consist of segmented structure and incorporate a submerged nozzle. During the combustion, the regression of the solid propellant surrounding the nozzle integration part leads to the formation of a cavity around the nozzle lip. The propellant combustion generates liquefied alumina droplets coming from chemical reaction of the aluminum composing the propellant grain. The alumina droplets being carried away by the hot burnt gases are flowing towards the nozzle. Meanwhile the droplets may interact with the internal flow. As a consequence, some of the droplets are entrapped in the cavity forming an alumina puddle (slag) instead of being exhausted through the throat. This slag reduces the performances.
The aim of the present study is to characterize the slag accumulation process in a simplified model of the MPS P230 motor using primarily optical experimental techniques. Therefore, a 2D-like cold-gas model is designed, which represents the main geometrical features of the real motor (presence of an inhibitor, nozzle and cavity) and allows to approximate non-dimensional parameters of the internal two-phase flow (e.g. Stokes number, volume fraction). The model is attached to a wind-tunnel that provides quasi-axial flow (air) injection. A water spray device in the stagnation chamber realizes the models of the alumina droplets, which are accumulating in the aft-end cavity of the motor.
To be able to carry out experimental investigation, at first the the VKI Level Detection and Recording(LeDaR) and Particle Image Velocimetry (PIV) measurement techniques had to be adapted to the two-phase flow condition of the facility.
A parametric liquid accumulation assessment is performed experimentally using the LeDaR technique to identify the influence of various parameters on the liquid deposition rate. The obstacle tip to nozzle tip distance (OT2NT) is identified to be the most relevant, which indicates how much a droplet passing just at the inhibitor tip should deviate transversally to leave through the nozzle and not to be entrapped in the cavity.
As LeDaR gives no indication of the driving mechanisms, the flow field is analysed experimentally, which is supported by numerical simulations to understand the main driving forces of the accumulation process. A single-phase PIV measurement campaign provides detailed information about the statistical and instantaneous flow structures. The flow quantities are successfully compared to an equivalent 3D unsteady LES numerical model.
Two-phase flow CFD simulations suggest the importance of the droplet diameter on the accumulation rate. This observation is confirmed by two-phase flow PIV experiments as well. Accordingly, the droplet entrapment process is described by two mechanisms. The smaller droplets (representing a short characteristic time) appear to follow closely the air-phase. Thus, they may mix with the air-phase of the recirculation region downstream the inhibitor and can be carried into the cavity. On the other hand, the large droplets (representing a long characteristic time) are not able to follow the air-phase motion. Consequently, a large mean velocity difference is found between the droplets and the air-phase using the two-phase flow measurement data. Therefore, due to the inertia of the large droplets, they may fall into the cavity in function of the OT2NT and their velocity vector at the level of the inhibitor tip.
Finally, a third mechanism, dripping is identified as a contributor to the accumulation process. In the current quasi axial 2D-like set-up large drops are dripping from the inhibitor. In this configuration they are the main source of the accumulation process. Therefore, additional numerical simulations are performed to estimate the importance of dripping in more realistic configurations. The preliminary results suggest that dripping is not the main mechanism in the real slag accumulation process. However, it may still lead to a considerable contribution to the final amount of slag.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Zidan, M. D. "Gas-liquid surface interactions." Thesis, University of Sussex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333478.
Повний текст джерелаVitorica, Inigo. "Solid state supramolecular chemistry : gas-solid reactions and intermolecular interactions." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3926/.
Повний текст джерелаZhang, Yonghao. "Particle-gas interactions in two-fluid models of gas-solid flows." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367375.
Повний текст джерелаKarimi, Mohsen. "CFD analysis of solid-liquid-gas interactions in flotation vessels." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86281.
Повний текст джерелаENGLISH ABSTRACT: A Computational Fluid Dynamics (CFD) model was developed for the prediction of flotation rate constants in a stirred flotation tank and validated against experimental data. The model incorporated local, time-varying values of the turbulent flow field into an existing kinetic flotation model based on the Generalised Sutherland Equation to predict the overall flotation rate constant. Simulations were performed for the flotation of various minerals at different operational conditions and the predictions were compared with experimental data. It was found that the CFD-based model yielded improvements in the prediction of flotation rate constant for a range of hydrophobicities, agitation speeds and gas flow rates compared with existing methodologies, which use volume-averaged empirical expressions for flow variables. Moreover, comparing to the available CFD alternatives for the flotation modelling this approach eliminates the need for solving an extra partial differential equation resulting in a more computationally economic model. The model was developed in three stages. In the first, a single-phase model was used to establish the requirements for successful modelling of the velocity components and turbulent properties of water inside flotation tanks. Also, a novel use of the Grid Convergence Index for this application was carried out, which allowed determination of the maximum achievable reduction in numerical uncertainties through systematic grid refinement and adaptation. All subsequent simulations were performed at the optimal discretization level determined in this manner. It was found that the Moving Reference Frames (MRF) method was adequate for representation of the impeller movement when the rotational zone was located close to the impeller, using a time step advance of between 10◦ and 15◦ of impeller rotation. Comparison of the different turbulence models for the single-phase modelling revealed that the standard k-e and Large Eddy Simulation turbulence models both performed equally well and that the computational requirement was lower for the standard k-e model, making it the method of choice. Validation of the methodology was done by comparison with experimental data for two different stirred tanks including an unbaffled mixer and a fully baffled standard Rushton turbine tank. The validation against experimental data showed that the model was capable of predicting the flow pattern, turbulent properties and the generation of trailing vortices. The second stage of modelling used an Eulerian-Eulerian formulation for gasliquid modelling of gas-sparged fully baffled vessels (2.25 l, 10 l and 50 l) using a Rushton turbine. It was determined that the minimum model uncertainty resulting from simulation of the sparger was achieved using a disk sparger with a diameter equal to 40% of the impeller diameter. The only significant interfacial force was found to be the drag force, and this was included in the multiphase methodology. A parametric study on the available formulations for the drag coefficient was performed which showed that the effect of turbulence on the air bubbles can accurately be represented using the proposed model of Lane (Lane, 2006). Validation of the methodology was conducted by comparison of the available experimental gas holdup measurements with the numerical predictions for three different scales of Rushton turbine tanks. The results verified that the application of the designed sparger in conjunction with Lane drag coefficient can yield accurate predictions of the gas-liquid flow inside the flotation tank with the error percentage less than 6%, 13%, and 23% for laboratory, pilot and industrial scale Rushton turbine tanks, respectively. The last stage of this study broadened the Eulerian-Eulerian framework to predict the flotation rate constant. The spatially and temporally varying flow variables were incorporated into an established fundamental flotation model due to Pyke (Pyke, 2004) based on the Generalized Sutherland equation for the flotation rate constant. The computation of the efficiency of the flotation sub-processes also incorporated the turbulent fluctuating flow characteristics. Values of the flotation rate constants were computed and volume-weight averaged for validation against available experimental data. The numerical predictions of the flotation rate constants for quartz particles for a range of particle diameters showed improvements in the predictions when compared with values determined from existing methodologies which use spatially uniform values for the important hydrodynamic variables as obtained from empirical correlations. Further validations of the developed CFD-kinetic model were carried out for the prediction of the flotation rate constants of quartz and galena floating under different hydrophobicities, agitation speeds and gas flow rates. The good agreement between the numerical predictions and experimental data (less than 12% error) confirmed that the new model can be used for the flotation modelling, design and optimization. Considering the limited number of CFD studies for flotation modelling, the main contribution of this work is that it provides a validated and optimised numerical methodology that predicts the flotation macro response (i.e., flotation rate constant) by integrating the significance of the hydrodynamic flow features into the flotation micro-processes. This approach also provides a more economical model when it is compared to the available CFD models for the flotation process. Such an approach opens the possibility of extracting maximum advantage from the computed parameters of the flow field in developing more effective flotation devices.
AFRIKAANSE OPSOMMING: 'n Wye verskeidenheid van industriële toepassings gebruik meganies geroerde tenks vir doeleindes soos die meng van verskillende vloeistowwe, verspreiding van 'n afsonderlike fase in 'n deurlopende vloeistoffase en die skeiding van verskillende komponente in ‘n tenk. Die hoofdoel van die tesis is om ‘n numeriese model te ontwikkel vir ʼn flotteringstenk. Die kompleksiteit van die vloei (drie-dimensioneel, veelvuldige fases en volledig turbulent) maak die voorspelling van die werksverrigting van die flottasieproses moeilik. Konvensioneel word empiriese korrelasies gebruik vir modellering, ontwerp en die optimalisering van die flotteringstenks. In die huidige studie word ‘Computational Fluid Dynamics’ (CFD) egter gebruik vir die modellerings doel, aangesien dit ‘n alternatief bied vir empiriese vergelykings deurdat dit volledig inligting verskaf aangaande die gedrag van vloei in die tenk. Die model is ontwikkel in drie agtereenvolgende stadiums. Dit begin met ‘n strategie vir enkelfase modellering in die tenk, vorder dan na ‘n gas-vloeistof CFD model en brei dan die tweede stap uit om ‘n CFD model te skep vir die skeidingsproses deur flottering. ‘n Enkelfase model, gebaseer op die kontinuïteits- en momentumvergelykings, dien as basis vir die flottasie model. Die ‘Multiple Reference Frames’ (MRF) metode word gebruik om die rotasie van die stuwer na te boots, terwyl die dimensies van die rotasie-sone gekies is om die gepaardgaande onsekerhede, insluitend die model- en numeriese foute veroorsaak deur die dimensies van die roterende sones, te verminder. Die turbulensie model studie het getoon dat die standaard k-e turbulensie model redelike akkuraatheid kon lewer in die numeriese voorspellings en die resultate verskil in gemiddeld net minder as 15% van die eksperimentele lesings, terwyl die rekenaartyd min genoeg was om die simulasies op 'n persoonlike rekenaar uit te voer. Verder het die ‘Grid Convergence Index’ (GCI) metode die inherente onsekerhede in die numeriese voorspellings gerapporteer en gewys dat die onderskatting van die turbulensie wat algemeen plaasvind reggestel kan word deur van ‘Large Eddie’ (LES) of ‘Direct Numerical Simulations’ (DNS) gebruik te maak. Die metode wat ontwikkel is, is op twee tipes geroerde tenks getoets, naamlik 'n onafgeskorte menger en 'n standaard Rushton turbine tenk. Die numeriese resultate is teen eksperimentele data gevalideer en het gewys dat die model in staat is om die vloeipatrone, turbulensie einskappe en die vorming van agterblywende vortekse te voorspel. Die CFD resultate het getoon dat die vloeipatroon twee simmetriese rotasies siklusse bo en onder die roterende sone vorm, terwyl die vlak van die ooreenkoms tussen die numeriese voorspellings van die turbulente eienskappe en die eksperimentele lesings met minder as 25% verskil. As die tweede stap van hierdie navorsing is 'n Eulerian-Eulerian struktuur ontwikkel vir die gas-vloeistof modellering binne 'n standaard Rushton turbine flotteringstenk. Soos vir die enkelfase modellering is die Reynolds spanningstensor opgelos deur die standaard k-e turbulensie model, terwyl die lugborrels ingevoer/versamel is in/van die tenk deurmiddel van bron/sink terme. Verskeie ‘sparger’ rangskikkings is in die tenk geïmplementeer om die onsekerheid in die model weens die metode van luginspuiting te verminder. Verder is verskillende korrelasies vir die sleursyfer vergelyk vir laminêre en turbulente vloei in die tenk. Daar is gevind dat die skyf ‘sparger’, met 'n deursnee gelykstaande aan 40% van die stuwer deursnee, in samewerking met die voorgestelde model van Lane (Lane, 2006) vir die bepaalde sleursyfer die naaste ooreenkoms met die eksperimentele metings lewer (met 'n gemiddelde verskil van minder as 25%). 'n Vergelykende studie is ook uitgevoer om die gevolge van die gas vloeitempo en roerspoed vir drie verskillende geroerde tenks met volumes van 2.5 l, 10 l en 50 l te ondersoek. Die resultate van hierdie afdeling bevestig dat die CFD metode in staat was om die gas-vloeistof vloei in die flotteringstenk korrek te voorspel. Die veelvuldigefase model wat ontwikkel is, is uitgebrei vir flottasie modellering. Dit behels die integrasie van die CFD resultate met die fundamentele flottasie model van Pyke (Pyke, 2004) vir die flotteringstempo konstant. Die CFD model is toegerus met Pyke se model deur aanvullende gebruiker gedefinieerde funksies. Die CFD-kinetiese model is geëvalueer vir die flottering van kwartsdeeltjies en die resultate het die geloofwaardigheid van die model bevestig, aangesien die gemiddelde verskil tussen die numeriese voorspellings vir die flotteringstempo konstante en die eksperimentele data minder as 5% was. Die resultate is ook vergelyk met die analitiese berekeninge van Newell en daar is bevind dat die model vergelykbare voorspellings van die flotteringtempo konstantes lewer, met die ‘root mean square deviations’ (RMSD) gelyk of minder as die RMSD waardes vir die analitiese berekeninge. Verdere ondersoeke van die CFD-kinetiese model bestaan uit 'n parametriese studie wat die gevolge van die roertempo, gas vloeitempo en die oppervlak hidrofobisiteit op die flottering van kwarts- en galenietdeeltjies bestudeer. Die aanvaarbare ooreenkoms tussen die numeriese voorspellings en eksperimentele data (oor die algemeen minder as 12% fout) bewys dat die nuwe model gebruik kan word vir flotterings modellering en optimalisering.
Abernathy, Harry Wilson III. "Investigations of gas/electrode interactions in solid oxide fuel cells using vibrational spectroscopy." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22638.
Повний текст джерелаAbernathy, III Harry Wilson. "Investigations of gas/electrode interactions in solid oxide fuel cells using vibrational spectroscopy." Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22638.
Повний текст джерелаCommittee Chair: Liu, Meilin; Committee Member: El-Sayed, Mostafa; Committee Member: Sanders, Thomas; Committee Member: Speyer, Robert; Committee Member: Wilson, Lane.
Shantharama, L. G. "The k-p interaction and carrier transport in GaAs, InP and related semiconductor alloys." Thesis, University of Surrey, 1986. http://epubs.surrey.ac.uk/848011/.
Повний текст джерелаGhasemian, Langeroudi Elahe. "Quantitative aspects of Co2-grafted amine interactions in gas-liquid-solid solubility equilibrium: Applications to Co2 capture." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27879/27879.pdf.
Повний текст джерелаGhasemian, Langeroudi Elahe. "Quantitative aspects of CO₂-grafted amine interactions in gas-liquid-solid solubility equilibrium : applications to CO₂ capture." Master's thesis, Université Laval, 2010. http://hdl.handle.net/20.500.11794/21467.
Повний текст джерелаBastos, Jaci Carlo Schramm Camara. "Analise experimental e numerica de um jato de dispersão gas-solido." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267143.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Apresenta-se nesta pesquisa uma análise experimental e numérica do comportamento da fase dispersa em um jato circular bifásico confinado e uma comparação com jato circular bifásico livre. Nas análises experimentais, uma câmara pentagonal em acrílico foi utilizada como sistema de confinamento para a obtenção de perfis axiais e radiais de velocidade média, flutuação de velocidade (RMS) e intensidade de turbulência. Estes dados foram analisados a fim de desenvolver uma análise completa da região desenvolvida do jato. Três diferentes jatos foram utilizados para a alimentação da fase gás no topo da câmara, mas apenas o jato central foi carregado com partículas entre 60 e 90µm de diâmetro. Os outros dois foram utilizados para proporcionar uma maior interação entre as fases no interior da câmara. A técnica óptica Phase Doppler Anemometry (PDA), foi empregada na medição da velocidade instantânea da fase sólida e do diâmetro das partículas nas diferentes posições axiais a partir do bico do jato. Nove casos de estudo distintos são investigados individualmente e, em seguida, comparados entre si. Estes casos fornecem informações importantes sobre o comportamento e o efeito do confinamento dos jatos sobre o transporte macrocóspico e turbulento das partículas entre o centro e as regiões de contorno do jato. As análises numéricas tratam da modelagem matemática tridimensional, turbulenta e transiente do escoamento no jato bifásico confinado. O modelo trata as fases gás e sólida a partir de uma abordagem Euleriana. O fechamento das equações de transporte foi realizado utilizando o modelo de turbulência de duas equações k-e para a fase gás e modelos de turbulência de zero-equação para a fase sólida, e ainda em alguns casos esta última apenas sofreu efeitos turbulentos advindos da fase contínua. A acurácia das previsões do modelo em um jato de partículas confinadas com as características médias no tempo, assim como os coeficientes da correlação de turbulência foram avaliados. Perfis radiais de velocidade média e fração volumétrica das partículas foram capturados em quarenta e dois níveis, subdivididos em nove casos e comparados aos dados experimentais adquiridos. O diâmetro médio das partículas utilizado nas simulações foi de 75µm e as velocidades iniciais utilizadas variam entre 3 e 11m/s no jato central. O modelo matemático previu um escoamento desenvolvido semelhante ao que foi encontrado experimentalmente.
Abstract: It is presented in this research an experimental and numerical analisys of the dispersed phase behavior in a circular confined two-phase jet and a comparison with circular free two-phase jet. In the experimental analysis, a pentagonal plexiglass chamber was used as confined system for the axial and radial profiles investigation of mean velocity, fluctuation velocity known as RMS velocity and turbulence intensity. These data were analyzed in order to develop a complete analysis in the developed region of the jet. Three different nozzles were used to feed the gas phase at the top of the chamber, but just the central nozzle was loaded with particles between 60 and 90µm of diameter. The other two were used to increase the interaction between the phases in the chamber. An optical technique known as Phase Doppler Anemometry was used to measure the instantaneous velocity of the solid phase and particle diameter in different axial positions of the jet nozzle. Nine different cases of study are investigated individually and then compared among each other. These cases provide important information about the jets behavior and the confinement effect on the macrocospic and turbulent transport of particles between the jet center and the jet contour regions. The numerical analysis deals with three-dimensional, turbulent and transient mathematical modeling of a confined two-phase jet flow. The model treats the gas and the solid phases from an Eulerian approach. The closure of the transport equations have been accomplished by using the k-e turbulence model for the gas phase and the zero-equation turbulence model for the solid phase, and in some cases the latter suffered turbulent effects occuring only from the continuos phase. The accuracy of the model predictions in a particle-laden confined jet with the characteristics as well as turbulence correlation coefficients have been evaluated. Radial mean velocity profiles for the solid phase were computed on forty two axial levels, subdivided in nine cases and compared to the obtained experimental data. The mean particle diameter used in the simulations was 75µm and the initial velocities used vary between 3 and 11m/s. The mathematical model predicted a flow development similar to that found experimentally.
Doutorado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
Groenewald, Ferdinand George. "Computational study of anion-anion intermolecular interactions between I3-ions in the gas phase, solution and solid state." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71786.
Повний текст джерелаXu, Yeping. "Synthesises of mesoporous materials and studies of host-guest interaction in mesoporous carbon by solid state NMR." Berlin mbv, Mensch-und-Buch-Verl, 2009. http://d-nb.info/995894957/04.
Повний текст джерелаGohlke, David Christopher. "Tuning the Properties and Interactions of Manganese Acceptors in Gallium Arsenide with STM." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354669837.
Повний текст джерелаVolk, Annette. "Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543139366302536.
Повний текст джерелаAlzahrani, Faris. "3D modelling by computational fluid dynamics of local interactions of momentum, mass and heat transfers with catalyst deactivation in gas-solid catalytic reactors of low aspect ratios." Thesis, Lancaster University, 2016. http://eprints.lancs.ac.uk/82666/.
Повний текст джерелаBréant, Christian. "Développement de lasers infrarouges accordables de haute pureté spectrale : application à la spectroscopie hyperfine des molécules HF et SF(6)." Paris 13, 1985. http://www.theses.fr/1985PA132010.
Повний текст джерелаSaad, Ali Sahal. "Synthèse de capteurs sélectifs destinés à la détection de NH³ et H²S pour le contrôle et la gestion de matières organiques en production de bio-énergies." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC096.
Повний текст джерелаThe thesis aims to develop microsystems gas sensors for selective detection of ammonia (NH3) and hydrogen sulfide (H2S). These sensors are dedicated to the control and production as well as security in the management of anaerobic digestion plants dedicated to bio-energy production. To do this,two types of chemical sensors were used for gas sensing. The first objective is the development of sensitive materials able to react with gaseous molecules and the physico-chemical characterization of matérials. Thus our choice focused on a polyaniline-based polymer composite (PANI-MWCNT/PS/PMMA) for the detection of NH3 and metal oxide (V2O5) nanoparticles for the detection of H2S. These materials were synthesized and exposed to gases to evaluate their sensors performances. Such an evaluation has given a proof that these materials were the best choice to respond positively to the target gases since they have shown higher sensitivity and stable responses even in a humid environment. In addition, these materials also showed a partial selectivity towards target gas
Grenier, Romain. "Etude multi-échelle des phénomènes physico-chimiques aux interfaces gaz – surfaces métalliques." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1113/document.
Повний текст джерелаIn the context of micro- and nano-flows, this work concentrates on the study of interactions at the interface of noble gas and metal surfaces by a multi-physics and multiscale model. Particularly, the interaction of an argon atom with a gold surface is the focus of the study. The work has been made in two steps: the first one occurred at the atomic scale in which Quantum Mechanics is employed and the second one at the nanoscale with the use of Molecular Dynamics.The first part of the work was devoted to the determination of interaction potentials between an argon atom and gold atoms from the surface by DFT calculation methods comporting long range effects. Two approaches, leading similar results, have been used: the first one is linked to a periodic description of the gold surface where electrons are defined by plane waves, the second one gives independently repulsive and attractive parts of the interaction of an argon atom with a small gold cluster. Those interaction potentials are then decomposed in pair potentials suitable for Molecular Dynamics simulations. These last ones consisted in multiple times projecting argon atoms on smooth or rough gold surfaces (which are more representative of the roughness of actual technologies). The statistical analysis of the reflected velocities yielded the tangential momentum accommodation (TMAC) coefficient of argon on gold surfaces. This coefficient is the transcription of slip phenomena which occur at the interface, and it can then be used in nano-flow simulations. The multi-physics approach of the thesis gives accurate TMAC values which are comparable to experiments. The accounted method could then be applied to other noble gas metal surface couples
Goble, Nicholas James. "ELECTRONIC TRANSPORT AT SEMICONDUCTOR AND PEROVSKITE OXIDE INTERFACES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1454002713.
Повний текст джерелаWang, TingTing. "Acoustic / elastic wave propagation in coupled-resonator waveguides." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCD061.
Повний текст джерелаWhen a defect is introduced into a phononic crystal, states localized at the defect appear in the band gaps. They decay rapidly far away from the defect. Therefore, it is possible to localize and guide wave propagation by designing defects in the perfect phononic crystal. Coupled-resonator waveguides based on the coupling effect between a sequence of defect cavities have simultaneously strong wave confinement and low group velocity, and can be used to design rather arbitrary circuits. Furthermore, the propagation of elastic waves in a solid matrix can be controlled through changing fluid fillings based on fluid-solid interaction. Thus, they have essential applications in vibration reduction and noise isolation. In this thesis, the acoustic and elastic waves propagating in both periodic and aperiodic coupled-resonator waveguides are investigated. The fluid-solid interaction in fluid/solid phononic crystals is studied. The work is conducted by combining numerical simulations, theoretical model analysis and experimental investigations
Galparsoro, Larraza Oihana. "Phonon and electron excitations in diatom abstraction from metallic surfaces." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0417/document.
Повний текст джерелаThe rationalization of elementary processes at surfaces is of prime importance for numerous natural and technological areas. From a fundamental pointof view, the way the energy concomitant to any chemical reaction is distributed among the desorbing molecules degrees-of-freedom and the surface is far frombeing fully pictured. In this work, quasiclassical molecular dynamics (QCT)simulations have been carried out to investigate this issue for the recombination ofH2 and N2 resulting from atomic adsorbate abstraction by atom scattering off theW(100) and W(110) covered surfaces, these processes being of relevance inplasma-wall interactions. Potential energy surfaces, built from density functional(DFT) theory calculations, have been used to simulate, within the framework ofclassical dynamics (including semi-classical corrections), the subpicosecond Eley-Rideal and Hot-Atom processes. The implementation of effective models to accountfor energy dissipation to surface phonons and electron-hole pair excitations, have allowed to rationalize the non-adidabatic dynamics of atom abstraction at metalsurfaces
Chen, Chih-Wei, and 陳熾緯. "The Simulation of Accretion Disk and Interaction of Gas-Solid Particle." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/71049036198901188819.
Повний текст джерела國立中央大學
天文研究所
92
We simulated the drift of particles in radial direction and surface density of accretion disk with considering the mass infall. The surface density of accretion disk will pass through growth phase, peak phase (about one hundred thousand years to million years), and decay phase. The drift of particle in the accretion disk with mass infall is different from the accretion disk without mass infall. There are two transient phenomena in the life time of accretion disks: FU-Orionis phenomenon and rapid disk dispersal. We adopted the ideas of large perturbation of surface density (Clarke et al, 1990) and photoevaporation model (Hollenbach et al, 1994) to explain these two transient phenomena. We also study the interaction between solid particles and gas in the accretion disk, and followed the results of Whipple (1972) and Weidenschilling (1977) to simulate the solid particle drift in the radial quiescent gas disks.
Frain, Matthew J. "Investigation of the influence of gas and solid particle interaction on the heat transfer effectiveness of a falling -bed heat exchanger." 2004. https://scholarworks.umass.edu/dissertations/AAI3136726.
Повний текст джерелаDieckmann, Gunther Hans. "Gas-solid precipitation reactions in lamellar solids ; Processing effects and substrate interactions in thin films of Bi₂CaSr₂Cu₂O₈₊x." 1988. http://catalog.hathitrust.org/api/volumes/oclc/19365454.html.
Повний текст джерелаRafique, Qureshi Muhammad Mushahid. "Flow characteristics and phase interactions of evaporating sprays in gas-solid suspensions." Thesis, 2007. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2007-027.
Повний текст джерелаMohammadzadeh, Alireza. "Moment method in rarefied gas dynamics: applications to heat transfer in solids and gas-surface interactions." Thesis, 2016. http://hdl.handle.net/1828/7626.
Повний текст джерелаGraduate
Lamorena, Rheo B., and Woojin Lee. "THE FORMATION OF CARBON DIOXIDE HYDRATE IN SOLID SUSPENSIONS AND ELECTROLYTES." 2008. http://hdl.handle.net/2429/1155.
Повний текст джерелаGrassa, F. "Geochemical processes governing the chemistry of groundwater hosted within the Hyblean aquifers." Thesis, 2002. http://hdl.handle.net/2122/416.
Повний текст джерела- Unione Europea Fondo Sociale Europeo; - Ministero dell’Università e della Ricerca Scientifica e Tecnologica; - Università degli studi di Palermo
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