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1
Pal, S. "Understanding flow of solid in continuous flow reactors." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2019. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5989.
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Duduta, Mihai. "Semi-solid redox flow battery." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/112499.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2010.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (page 53).<br>materials used in Li-ion batteries and the design and functioning of a redox flow cell. The use of Li-ion battery materials offers significant increases in energy and power density (200 Wh/kg compared to 25-35 Wh/kg for current commercial vanadium redox batteries). The implementation of a redox flow system allows for energy to be stored outside the cell and for the power and energy of the battery to be decoupled. A proof of concept is achieved by successful cycling of anode and cathode suspensions under intermittent flow conditions. The importance of materials' stability to cell life, energy and power densities is discussed. The high energy densities may enable the use of the proposed system in a variety of application, ranging from grid-level storage to fully electric charge.<br>by Mihai Duduta.<br>S.B.
3
Brocken, Laurens. "Polymerisation in flow and solid state." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11918/.
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The aim of this thesis was to develop and facilitate new approaches to polymer synthesis. The chosen tools for this task were flow chemistry and topochemical polymerisation. Flow chemistry has proven its strength in the past and is a technique suitable for performing synthesis at scale. Three areas were explored in this thesis. In the first results chapter the free radical polymerisation of aqueous solution of acrylic acid (7) has been studied using a continuous flow reactor to quickly screen reaction parameters such as temperature, residence time, monomer- and initiator concentration. The experimental data sets produced established a theoretical basis for conducting scale up processes to efficiently produce larger quantities of poly(acrylic acid) (8) delivered with good control over the molecular weight and dispersity. The data sets were used to study the ability to synthesise polymers on demand. The developed methodology to synthesise aqueous soluble polymers in flow, possessing a variety of molecular weights and dispersities have been achieved. However, full conversion was hard to achieve without increasing the dispersity and purification was therefore necessary. The second results chapter studied the direct purification to obtain purified polymer under one hour. This opened up a new way to synthesise and isolate polymers. Performing a free radical polymerisation in flow does not result in the control over tacticity of the polymerisation. The third results chapter studied the synthesis of polymers via topochemical polymerisation and the advantages it can add to general polymer synthesis.
4
Narayanan, Thaneer Malai. "Development of semi-solid alkaline flow battery." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120228.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 72-80).<br>Flow battery is an attractive energy storage system due to its ability to decouple power and energy outputs, and its less stringent geometric requirement. However, commercial flow battery technology suffers from low energy density (~z40 Wh/Lcatholyte), high membrane cost (~$ 500/M 2 and species crossover. One elegant method to overcome all this problems is utilize flowable semisolid electrode. Although there have been several reports in the literature regarding performance of various semi-solid flow batteries, there is still lack of understanding on how to design the suspension electrode and its impact on flow cell design and performance. In this thesis, we emphasize on three main properties, namely stability, conductivity and flowability for high performing suspension electrode for Zn-Ni alkaline battery chemistry. Firstly, we recognized interplay of forces acting on particles in a suspension electrode and designed suspending medium with jammed Carbopol© microgel structures to prevent sedimentation of the large particles. Secondly, we determined percolation threshold of conductive additive and investigated its effect on electrochemical performance of the semi-solid electrodes in a closed static cell. We found that conductive additive concentration should be well above percolation threshold to obtain maximum discharge capacity of Ni(OH)2. Thirdly, based on the understanding from conductivity and stability of the suspension, we designed catholyte (~ 5 M Ni(OH)2) and tested its electrochemical performance in a static cell. We were able to achieve energy density of 137 Wh/Latholyte, about 3 times of commercial flow battery. We then assessed flowability of the suspensions. Catholyte and anolyte had yield stress of 204 Pa and 447 Pa respectively. We found that by choosing appropriate flow cell stack design energy loss due to pumping can be minimized to < 1% for continuous flow. Finally, flow cells were designed to test the electrochemical performance of these suspensions in an open system.<br>by Thaneer Malai Narayanan.<br>S.M.
5
Isa, Maryam Binte Mohd. "Microwave radar sensor for solid flow measurement." Thesis, University of Manchester, 2006. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488369.
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Industrial flow measurement is a challenging area and in high demand. Tremendous research has been carried out to improve and solve problems in the flow measurement system. Thus, new techniques are produced and a wider range of flow measurement solutions have become available in market. This study has introduced a new technique that is useful and proves to be applicable in industrial flow measurement system. Microwave Doppler radar sensor was used to extract useful information of the solid flow characteristics. The amplitude level of the Doppler signal is analysed instead of the frequency shift that is normally used in conventional Doppler radar sensor. The relation between the amplitude level and the characteristic of the flow was determined to define the characteristics of the flow. The solids weight and dimension are among the characteristics that are investigated in this study. Microwave sensor circuits based on Doppler radar technique operating at 2.45GHz and 10.58GHz were designed, constructed and tested. The 2.45GHz system was built in the initial study and pre-testing of the Doppler radar sensor system prior to the construction of the 10.58GHz system that was later used for the measurement purposes. The antennas and circuit analyses were carried out in building an optimum sensor system. Two-antenna and two-antenna with copper plate are two new antenna configurations that are applied in single solid flow measurement analysis. The flow measurements were carried out using different types of solids ranges from 4mm to 20mm sizes and 0.02g to 0.63g of weight for single and multiple solids flow. The linear relations of the reflected power and the solids characteristics determined from the analyses are found to be useful in differentiating the type of solids and measuring the total weight of solids flowing.
6
Malekzadeh, Mohammad Jafar e. "Flow of liquid-solid mixtures down inclined chutes." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41702.
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The ability to model and predict debris flows, mudflows and sediment transport is currently hindered by a poor understanding of the fundamental aspects of solid-liquid flows. The present work attempts to further our knowledge through experimental studies of flows of highly concentrated, solid-liquid suspensions down inclines.<br>Preliminary experiments, measuring grain velocities for two sizes of sand and two surface inclination angles were performed in a tank of stationary water. When sub-aqueous debris flows were developed by releasing Ottawa sand from a hopper onto a rough bed, various phenomena were observed: nonuniform flows, static dead-flow regions, uniform flows and roll waves. Uniform flow was possible for a range of bed inclination angles larger than the angle of internal friction of the sand. The flow became unstable and roll waves developed at higher slopes and lower depths of flow.<br>Following these exploratory experiments, more detailed, controlled experiments were carried out using a non-intrusive method of velocimetry. The flowing mixture was made up of glass particles and a liquid having the same index of refraction. By passing planes of laser light through the free surface of flows at various distances from the glass sidewalls of the channel and recording video images, it was possible to identify the particles and determine the three-dimensional velocity and concentration profiles. Experiments were performed for various bed inclination angles.<br>Further experiments were performed with the aim of correlating the data in the form of a generalized Vedernikov formula for debris flows that relates velocity, flow depth, concentration and bed inclination angle. Various liquid-solid mixtures were used, and the variations of the average velocity with depth and sloped inclination angle were studied for different discharge-rates and solids fractions. Very different behavior was observed for the macro-viscous and transitional regimes, as defined by Bagnold. Such correlation was obtained for the macro-viscous regime; the nondimensional parameters that appear in the model involve the particle diameter, density and concentration and fluid viscosity and density. The model was compared with about 200 sets of data and good agreement was obtained.
7
Cooper, Richard John. "Flow and reaction in solid oxide fuel cells." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367622.
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Lareo, Claudia. "The verticle flow of solid-liquid food mixtures." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242999.
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9
Liu, Shi. "The horizontal flow of solid-liquid food mixtures." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307898.
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10
Brunini, Victor Eric. "Modeling and design of semi-solid flow batteries." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79549.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 111-116).<br>A three-dimensional dynamic model of the recently introduced semi-solid flow battery system is developed and applied to address issues with important design and operation implications. Because of the high viscosity of semi-solid flow battery suspensions, alternative modes of operation not typically used in conventional redox flow battery systems must be explored to reduce pumping energy losses. Modeling results are presented and compared to experimental observations to address important considerations for both stoichiometric and intermittent flow operation. The importance of active material selection, and its impact on efficient stoichiometric flow operation is discussed. Electrochemically active zone considerations relevant to intermittent flow operation of semi-solid flow batteries (or other potential electronically conductive flow battery systems) are addressed. Finally, the use of the model as a design tool for optimizing flow channel design to improve system level performance is demonstrated.<br>by Victor Eric Brunini.<br>Ph.D.
11
Djennas, Farid 1955. "Permeability models for flow in partially solid alloys." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/191880.
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In order to characterize the flow of interdendritic liquid through the solid-liquid zones of solidifying alloys, it is necessary to have permeability data. Permeability data from five different sources were analyzed by using models based upon the volume fraction of liquid, and the primary and secondary dendrite arm spacings. Three different models were tested, of which two have a physical basis: the Blake-Kozeny model and the Hagen-Poiseuille model; the third model is empirical. Metal as well as nonmetal specimen data were used in this study. The fraction liquid range for all data varied from 0.077 to 0.606, the primary dendrite arm spacing from 28 pm to 420 pm and the secondary dendrite arm spacing from 23 pm to 146 pm. Data for flow parallel as well as perpendicular to the primary dendrite arms were used in order to model the two-dimensional permeability. For parallel flow, the Hagen-Poiseuille model gives the best agreement between calculated and measured permeabilities with an average deviation of 37 percent. However for normal flow, the empirical model gives the best results with an average deviation of 44 percent between calculated and measured permeabilities, and the Blake-Kozeny model correlates almost as well.
12
Kolnaar, J. W. H. "A temperature window of reduced flow resistance in polyethylene with implications for melt flow rheology." Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357887.
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Lowe, C. "CFD modelling of solid propellant ignition." Thesis, Cranfield University, 1996. http://hdl.handle.net/1826/3921.
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Solid propellant is the highly energetic fuel burnt in the combustion chamber
of ballistic weapons. It is manufactured, for this purpose, in either granular
or stick form. Internal ballistics describes the behavior within the combustion
chamber throughout the ballistic cycle upto projectile exit from the muzzle of
the gun barrel. Over the last twenty years this has been achieved by modelling
the process using two-phase flow equations.
The solid granules or sticks constitute the first phase, which can be assumed
to be incompressible over typical pressure ranges within the chamber. The
gas-phase is composed of both the original ambient gas contained around the
propellant and additional gas produced by the propellant gasifying on heating.
Equations can be derived that describe the conservation of mass, momentum
and energy in terms of average flow variables. The equations are a highly
non-linear system of partial-differential- equations. High-speed flow features
are observed in internal ballistics and ordinary fini te- difference methods are
unsuitable numerical methods due to inaccurate prediction of discontinuous
flow features. Modern shock-capturing methods are employed, which solve the
system of equations in conservation form, with the ability to capture shocks
and contact discontinuities.
However, although the numerical solutions compare well with experiment
over the bulk of the combustion chamber, the ignition models used in internal
ballistics are unreliable. These are based on either gas or solid-surface temperature
achieving some empirically measured 'ignition temperature' after which
the propellant burns according to an empirical pressure dependent burning
law. Observations indicate that this is not an adequate representation of ignition.
Time differences between first solid gasification and ignition imply two
distinct processes occurring. ]Further, ignition occurring in gas-only regions
indicates that ignition is controlled by a gas-phase reaction.
This thesis develops simple ideas to describe possible mechanisms for these
physical observations. The aim is to provide an improved model of the ignition
of solid propellant. A two stage reaction process is described involving
endothermic gasification of the solid, to produce a source of reactant gas, followed
by a very exothermic gas-phase ignition reaction.
Firstly the gas-phase ignition is considered. A very simple reaction is suggested
which is assumed to control the combustion of reactant gas, produced
by solid gasification. Ignition is, by definition, the initiation of this exothermic
reaction. Chemical kinetics are included in the gas-phase flow equations to explore the evolution of the reactant gas that is subject to changes in temperature
and pressure. By assuming spatial uniformity, analytical solutions of the
problem are deduced. The physical interpretation of the solution is discussed,
in particular, the relationship between temperature, reactant concentration
and ignition is explored.
Numerical methods are required to solve the one-dimensional flow equations.
Development of suitable CFD methods provides a method of solution.
Finite-volume schemes, based on the original work by Godunov, are used to
solve the conservation form of the equations. A simple test problem is considered
whereby reactant gas is injected into a cylindrical combustion chamber.
By examining the resulting flow histories, valuable information is gathered
about the complicated coupling of chemistry and flow.
Chemistry is included into a system of two-phase flow equations. By using
standard averaging methods along with an equation for gas-phase species,
equations are derived that describe the rate of change of average flo%v variables
for both gas and particle phases. Numerical schemes are developed and
some of the difficulties involved in two-phase flow systems, that are not an
issue in single-phase flow, are presented. An internal ballistics application is
considered as a test case and the solution discussed.
The other important reaction involved in the combustion cycle, solid gasification,
is explored. The model is based on detailed description of interphase
mass and energy transfer at the solid-gas interface. This involves the solution
of the heat conduction equation with a moving boundary that divides the
solid and gas regions. Similar numerical schemes are constructed to solve the
equations. Finally, this model is coupled with the equations of gas-phase reaction.
This describes the complete cycle whereby increases in gas temperature
cause the solid to increase in temperature and gasify. Subsequent gas-phase
combustion of the reactant gases produces heat-transfer between the solid and
gas and continues to accelerate gasification. Eventually this results in selfsustained
combustion of the solid propellant.
14
Li, Fan. "Study of bubble flow in gas-solid fluidized beds." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0018/MQ55262.pdf.
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Petkovic, Bojan. "Deposition of droplets onto solid objects in aerosol flow." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/20891.
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In this work, the effect of velocity on deposition coefficients and capture efficiencies on a circular disk, placed normal to an aerosol flow was investigated. The superficial gas velocity was varied in the range of 0.1 m/s to 1.5 m/s, while the volume median diameter of the droplet size distribution varied between 3.9 and 7.5 microns. The morphology and distribution of deposits on the upstream and downstream surface of the disk were observed and measured. The effect of contact angles (20°, 51°, 94°) on deposition, and dry vs. wet surface effects were also investigated. It was found that in the range of velocity and droplet sizes investigated, deposition on the upstream side was dominated by the inertial impaction mechanism. Capture efficiencies increased with velocity and droplet size, and could be explained by the inertial impaction mechanism from the upward flow, using the potential flow approximation. For the downstream side, capture efficiencies increased with droplet size and showed a minimum with velocity. It is postulated that the governing deposition mechanism for the downstream side is the inertial impaction mechanism with gravity in the flow direction.
On the upstream side, it was found that deposits were concentrated closer to the coupon edge, while on the downstream side, the distribution of deposits on the surface was uniform. In the range of investigated contact angles, there was no significant difference observed between the deposition rates. The same can be said for the effect of dry vs. wet coupon surface.
16
Dauphinais, Guillaume. "Fabrication, structural relaxation, and flow in solid-state nanopores." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107651.
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Single solid-stat nanopores have been fabricated in free-standing layers of amorphous silicon nitride. Using a focused electron beam and a focused ion beam, diameters ranging from about 0.7 nm to a few hundred nanometerswere achieved. Structural relaxation of nanopores fabricated by focused electron beam was observed. Depending on the initial diameter and on the length of the nanopores, two distinct phases for the relaxation process were found. An experimental setup for themeasurement of pressure-driven mass flow of helium through a single nanopore was built. The conductance of nanopores with diameters ranging from 25 nm to 315 nm was measured. A semi-phenomenological model was developed and it was shown to quantitatively describe the conductance of fluid through a short cylindrical nanopore.<br>Des nanopores ont été fabriqués dans de minces couches suspendues de nitrure de silicium amorphe. En utilisant un faisceau d'électrons focalisé et un faisceau d'ions focalisé, des diamètres entre 0.7 nm et 315 nm ont été obtenus. La relaxation struturelle de nanopores fabriqués par faisceau focalisé d'électrons a été observée. Dépendamment du diamètre inital du nanopore et de sa longueur, deux phases distinctes ont été identifiées. Un montage expérimental permettant la mesure de l'écoulement de masse d'hélium causé par l'application d'une différence de pression a été réalisé. La mesure de conductance de nanopores ayant un diamètre compris entre 25 nm et 315 nm a été effectuée. Un simple modèle phénoménologique permet de décrire quantitativement l'écoulement de gaz dans un court nanopore cylindrique.
17
Ganeshalingam, Jeyakumar. "Swirl-induction for improved solid-liquid flow in pipes." Thesis, University of Nottingham, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.655744.
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Luu, Trang (Trang N. ). "Solid particles flow through labyrinth channels in drip emitters." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119949.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 24-25).<br>Clogging of drip irrigation emitters can reduce the effectiveness of drip irrigation systems. The most common way of studying clogging in a laboratory setting is to recreate the actual timing conditions of on-site drip irrigation systems. However, this requires a clogging period on the order of hours to days and an intermission period on the order of days to weeks. This thesis explores the recreation of actual drip irrigation clogging effects in lab in a shorter amount of time, using water highly concentrated with grit particles. Three different non-pressure compensating emitters with rated flow rate of 0.8 LPH, 1.6 LPH, and 2.0 LPH from Jain Irrigation System were studied. Eight different concentrations of grit were pumped through the system. A clogging period of 30 minutes and an intermission period of 30 minutes were used in the tests. The grit used was aluminum oxide sized at 180 microns. The flow rate and discharged from each emitter were measured and calculated. The data showed a significant amount of clogging with high grit concentrations. This thesis will serve as the first part to achieving a short term clogging procedure for drip irrigation that will significantly allow more emitters designs to be tested and improved upon in shorter amount of time.<br>by Trang Luu.<br>S.B.
19
Incera, Garrido Gerardo. "Mass and momentum transfer upon flow through solid sponges." [S.l. : s.n.], 2008. http://digbib.ubka.uni-karlsruhe.de/volltexte/1000010087.
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Booth, Jonathan. "The mechanism of solid-liquid interactions." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337524.
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Miller, Ryan Michael. "Continuum Modeling of Liquid-Solid Suspensions for Nonviscometric Flows." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4864.
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A suspension flow model based on the "suspension balance" approach has been developed. This work modifies the model to allow the solution of suspension flows under general flow conditions. This requires the development of a frame-invariant constitutive model for the particle stress which can take into account the spatially-varying local kinematic conditions. The mass and momentum balances for the bulk suspension
and particle phase are solved numerically using a finite volume method. The particle stress is based upon the computed rate of strain and the local kinematic conditions. A nonlocal stress
contribution corrects the continuum approximation of the particle phase for finite particle size effects. Local kinematic conditions are accounted through the local ratio of rotation to extension in the flow field. The coordinates for the stress definition are the local principal axes of the rate of strain field.
The developed model is applied to a range of problems. (i) Axially-developing conduit flows are computed using both the full two-dimensional solution and the more computationally
efficient "marching" method. The model predictions are compared to experimental results for cross-stream particle concentration profiles and axial development lengths. (ii) Model
predictions are compared to experiments for wide-gap circular Couette flow of a concentrated suspension in a shear-thinning liquid. With minor modification, the suspension flow model predicts the major trends and results observed in this flow. (iii) Comparisons are made to experiments for an axisymmetric contraction-expansion. Model predictions for a two-dimensional planar contraction flow test the influence of model formulation. The variation of the magnitude of an isotropic particle normal stress with local kinematic conditions and anisotropy in the
in-plane normal stresses are both explored. The formulation of the particle phase stress is found to have significant effects on the solid fraction and velocity. (iv) Finally, for a rectangular
piston-driven flow and an obstructed channel flow, a "computational suspension dynamics" study explores the effect of particle migration on the bulk flow field, system pressure drop
and particle phase composition.
22
Du, Bing. "Hydrodynamics and flow structure, gas and solids mixing behavior, and choking phenomena in gas-solid fluidization." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1110208922.
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Thesis (Ph. D.)--Ohio State University, 2005.<br>Title from first page of PDF file. Document formatted into pages; contains xxvii, 334 p.; also includes graphics (some col). Includes bibliographical references (p. 322-334). Available online via OhioLINK's ETD Center
23
Sen, Firat. "Thermal Management Of Solid Oxide Fuel Cells By Flow Arrangement." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614496/index.pdf.
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Solid oxide fuel cell (SOFC) is a device that converts the chemical energy of the fuel into the electricity by the chemical reactions at high temperatures (600-1000oC). Heat is also produced besides the electricity as a result of the electrochemical reactions. Heat produced in the electrochemical reactions causes the thermal stresses, which is one of the most important problems of the SOFC systems. Another important problem of SOFCs is the low fuel utilization ratio. In this study, the effect of the flow arrangement on the temperature distribution, which causes the thermal stresses, and the method to increase the fuel utilization, is investigated.
An SOFC single cell experimental setup is developed for Cross-Flow arrangement design. This setup and experimental conditions are modeled with Fluent®<br>. The experimental results are used in order to validate and verify the model. The model results are found to capture with the experimental results closely. The validated model is used as a reference to develop the models for different flow arrangements and to investigate the effect of the flow arrangement on the temperature distribution. A method to increase the SOFC fuel utilization ratio is suggested. Models for different flow arrangements are developed and the simulation results are compared to determine the most advantageous arrangement.
24
Xu, Bao Hua. "Numerical simulation of the gas-solid flow in fluidized beds." Online version, 1997. http://bibpurl.oclc.org/web/22135.
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Masnadi-Shirazi, Mohammad Sadegh. "Mal-distribution of gas-solid flow through identical parallel paths." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/9708.
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Two-phase flow in identical parallel paths is associated with various industrial applications in which the two phases are distributed among parallel branches, with common inlet and outlet manifolds. Evidence in the literature shows that the distribution of multi-phase flow travelling through identical parallel paths can be significantly non-uniform. This may have many harmful operating consequences in practice.
In order to provide a better understanding of this fluid mechanics phenomenon, a fundamental analytical and numerical study is performed on the distribution of gas-solid pneumatic flow passing across a ‘Y branch’. While many steady-state gas-solid distribution solutions, including a uniform distribution, are the outputs of the governing equations, instability analysis is performed to examine the stability of the solutions. In addition, the behaviour of the system is analysed using computational fluid dynamics. The results indicate that the uniform distribution is the stable output in this case.
Next the distribution of gas-solid flow through identical parallel cyclones is investigated based on an analytical model which includes a semi-empirical equation from the literature for cyclone pressure drop. Using the proposed model, many steady-state distribution solutions are obtained. The solution with maximum energy consumption is considered as the unlikely solution of the system. The results indicate that the non-linearity of the system can cause the distribution to be non-uniform for high solids loadings, whereas lower loadings will result in distributions that are uniform, or so close to being uniform that experimental results will not be able to distinguish difference between the flows. Moreover a number of experimental studies were carried out for a pair of identical standard cyclones of diameter 101.6 mm on the distribution of dilute gas-solid flow. The results are compared with the proposed cyclone model. The model can be used for multi-paths (>2) as well. Finally, available techniques, to make the distribution of gas-solid flow through parallel paths uniform, are presented.
26
Khokhar, Muhammad Y. "Flow injection immunoassays using solid phase immunoreactors and fluorescence detection." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/12384.
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The use of flow injection analysis with fluorescence detection was evaluated using the host-guest phenomenon between the cyclodexnins and DL-Iysine and Lserine. Auorescence enhancement, kinetic and equilibrium studies were recorded and the effect of pH and time on fluorescence were also observed. Rhodamine isothiocyanate was conjugated to insulin. Insulin and dye were mixed in different ratios, and the dye : insulin ratio was detennined for each conjugate. These conjugates were checked for immunoreactivity. Insulin-biotin and antibody-iminobiotin conjugates were also prepared. Insulin : biotin ratio was also determined. An insulin-biotin avidin-Texas Red complex was also prepared. Each was checked for immunoreactivity. Protein G-agarose, protein A-controlled pore glass(CPG), streptavidin-agarose, and avidin D-agarose-biotin-antibody solid phase immunoreactors were used in flow injection immunoassay of insulin. In these immunoassays, antibody, insulin and labelled insulin were incubated in vitro and then injected onto the immunoreactor. A binding buffer carried the sample through the immunoreactor and a fluorescent detector. An acidic buffer then eluted the components of the sample bound to the immunoreactor, which were then measured. An assay range for insulin was developed in each solid phase assay.
27
CORDEIRO, HELIO DE MIRANDA. "FLOW FIELD COMPUTATIONAL ANALYSIS IN A SOLID FUEL RAMJET COMBUSTOR." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3283@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>Essa dissertação realiza uma análise do escoamento reativo
e turbulento no interior do combustor de um estato reator a
combustível sólido. Investiga-se diferentes modelos para
prever a pirólise do combustível sólido. O modelo
matemático é baseado na solução numérica das equações de
conservação de massa, quantidade de movimento linear,
energia e equações de transporte para quantidades
escalares. O modelo de turbulência empregado é o (constante
de Von Kármán -taxa de dissipação da energia cinética
turbulenta) para altos Reynolds e na modelagem da combustão
emprega-se o formalismo da fração de mistura/função
densidade de probabilidade prescrita. Próximo às paredes, a
lei da parede é usada, sendo a camada limite dividida em
duas regiões, uma subcamada laminar e uma região totalmente
turbulenta. As transferências de calor e massa para as
paredes são calculadas utilizando-se a lei da parede
modificada com uso de um parâmetro de transferência de
massa. Os resultados obtidos através do modelo proposto
foram comparados com os resultados obtidos anteriormente com
outros modelos e com dados experimentais, verificando-se
que os mesmos apresentam um boa concordância com os dados
existentes na literatura, concluindo-se que o modelo é
satisfatório para o problema proposto.<br>This dissertation presents an analysis of reactive and
turbulent flow field in a solid fuel ramjet combustor. The
ability of different models to predict solid fuel
pyrolysis is investigated. The mathematical model is based
on the numerical solution of the conservation equations of
mass, momentum, energy and transport equations for scalar
quantities. The energia cinética turbulenta - taxa de
dissipação da energia cinética turbulenta for high Reynolds
turbulence model is employed and the combustion is modeled
with the mixture fraction/prescribed probability density
function formalism. Close to the walls the law-of-the-wall
is specified, with the boundary layer divided into two
regions, a viscous sublayer and a fully turbulent region.
Heat and mass transfer at the walls are calculated using a
modified law-of-the-wall based on a blowing parameter. The
results obtained using the proposed model were compared
with other earlier models predictions and with empirical
data. It was verified that the results are in good
agreement with literature data, allowing to conclude that
the model presented is suitable for the prediction of the
mas s transfer and flow field in a solid fuel ramjet
combustor.
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Wang, Fei. "Gas-Solid Fluidization: ECVT Imaging and Mini-/Micro-Channel Flow." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1290390285.
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Marsh, Adrian Michael. "Superconducting contacts and supercurrent flow in a GaAs/AlGaAs heterojunction." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387688.
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Rattray, P. "Pulsed flow and time-resolved dielectric spectroscopy of electrorheological fluids." Thesis, Cranfield University, 1994. http://dspace.lib.cranfield.ac.uk/handle/1826/10508.
Full textAbstract:
Research has been undertaken into the dielectric and rheological properties of
electrorheological (ER) fluids. The fluids studied were based on acene-quinone radical
polymers made within the department dispersed in silicone oil. A commercial
poly(1ithium methacrylate) dispersion was also examined.
As a means of
probing the underlying mechanisms of the E phenomenon, the
permittivity of the fluids was measured from 12 Hz to 100 kHz under both static and
dynamic conditions. Results indicated that a interfacial polarization process was taking
place.
A series of visual observations were made of fluids under different fielding patterns.
A series of
photographs were taken that illustrated the structure formation with elapsed
time in a dilute fluid. Also photographs were taken of the final structure formed under
different field conditions. ..
To
perform permittivity measurements of the fluid when a electric field was applied,
a
high voltage biasing unit was designed, built and proved. This allowed the application
of a continuous DC electric field of up to 3 kVmm" and the permittivity to be
measured from 150 H t 100 kl-Iz. Through a series of experiments it was found that
the low
frequency permittivity increased with increasing electric field. This result was
partially explained by the Sillars model.
The fluids were also subjected to shear rates from 1500 to 60 s". Flow modified
permittivity resonances were found at the predicted frequencies. However, the resonant
frequency did not move significantly under the application of a electric field.
The
structuring process was time resolved and a model was made to predict the sealing
of the characteristic structuring time. The rheological response of the fluids when
subjected
t pulsed DC fields was examined and found to be dominated by a
instrumentational effect.
Al
experimental procedures are given along with a comprehensive examination of the
equipment. The results are discussed as they occur in terms of the models appropriate
to that
particular event.
31
Leahy, Scott B. "Active Flow Control of Lab-Scale Solid Polymer Electrolyte Fuel Cells." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5188.
Full textAbstract:
The effects of actively pulsing reactant flow rates into solid polymer electrolyte fuel cells were investigated in this thesis. First, work was conducted to determine the magnitude of voltage response to pulsed reactant flow on a direct hydrogen proton exchange membrane (PEM) cell. The effects of pulsed reactant flow into a direct methanol fuel cell (DMFC) were then considered.
The PEM work showed substantially greater response to pulsed air flow than to pulsed fuel flow. It was found that several parameters affect the magnitude of cell response to active flow control (AFC). Increasing current load, increasing the magnitude of flow oscillation, decreasing the frequency of oscillation, and decreasing the average level of excess reactant supplied were found to maximize both the level of voltage oscillations and the decrease in cell power from steady state performance. Greater response to pulsed oxidant flow is believed to have been observed due to effects brought about by changes in membrane humidity.
In contrast, pulsed fuel flow showed the greatest response in the study of DMFC technology. In this case, time averaged cell voltage was found to increase as the time averaged fuel flow rate was reduced. The increase in average cell power is the result of a reduction in methanol crossover; sustainable increases of up to 6% in power output were measured. The parameters found to effect the increase in cell power observed include the frequency of oscillation and the time-averaged NOSfuel. Pulsed air flow on the DMFC did not show any such rise in voltage, supporting the hypothesis that a reduction in methanol crossover is the phenomenon which brings about enhanced performance.
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Politis, Spyridon. "Prediction of two-phase solid-liquid turbulent flow in stirred vessels." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/8708.
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Tremel, Alexander [Verfasser]. "Reaction Kinetics of Solid Fuels during Entrained Flow Gasification / Alexander Tremel." München : Verlag Dr. Hut, 2013. http://d-nb.info/1031843787/34.
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Yurko, James Andrew 1975. "Fluid flow behavior of semi-solid aluminum at high shear rates." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8451.
Full textAbstract:
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2001.<br>"June 2001."<br>Includes bibliographical references (leaves 119-127).<br>The rheological behavior and microstructure of semi-solid aluminum alloys were studied using a novel apparatus, the Drop Forge Viscometer (DFV). The viscometer determines force from the curvature of displacement data allowing calculations of viscosities at shear rates in excess of 1000 s-1. Alternatively, the DFV can be operated like a conventional parallel-plate compression viscometer, attaining shear rates as low as 10-5 s-1. Durations of an experiment range between approximately 5 ms and 24 hours. Most rapid compression tests resulted in periods of first rapidly increasing shear rate followed by rapidly decreasing shear rate. Viscosity during the increasing shear rate period decreased by 1-2 orders of magnitude. The viscosity during the decreasing shear rate was an order of magnitude smaller (relative to another experiment) when it achieved a 75% greater maximum shear rate. The DFV was used to calculate viscosity as a function of shear rate for Al-Si and Al-Cu alloys that were rheocast with the commercial SIMA and MHD processes, as well as the recently developed MIT method. Experiments were conducted between fractions solid of 0.44 and 0.67. Viscosity of A357 produced by the three processing routes all had similar viscosities, ranging from 300 Pas at 120 s-1 to 2.2 Pas at 1500 s-1. The final height of compressed Al-Cu was always greater than Al-Si for a given set of experimental conditions. Segregation was not observed in rapid compression experiments shorter than 10 ms, either visually or with EDS characterization. At low compression velocities, segregation was observed and increased with the amount of strain.<br>by James Andrew Yurko.<br>Ph.D.
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Chen, Rong-Che. "Experimental and numerical studies of solid-liquid multiphase flow in pipes." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055532292.
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Behera, Narayana. "On the solutions of fluid flow and solid deformation interaction problems /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487777901658103.
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Dong, Xuefeng Materials Science & Engineering Faculty of Science UNSW. "Modelling of gas-powder-liquid-solid multiphase flow in a blast furnace." Awarded by:University of New South Wales. School of Materials Science and Engineering, 2004. http://handle.unsw.edu.au/1959.4/20808.
Full textAbstract:
The ironmaking blast furnace (BF) is a complex reaction vessel involving counter-, coand/ or cross-current flows of gas, powder, liquid, and solids. However, the interactions of these multiphase flows have not been completely understood. The objective of this thesis is to develop a suitable model to simulate the powder flow and accumulation in packed beds and then extend it to numerically investigate the multiphase flow in the furnace. Gas-powder flow in a slot type packed bed has been experimentally studied in order to understand the flow and accumulation behaviour of powder in systems like an ironmaking blast furnace. A variety of variables including gas flowrate, powder flowrate and packing properties have been taken into consideration. It is found that a clear and stable accumulation region can form in the low gas-powder velocity zone at the bottom of the bed. The accumulation region is stable and shows strong hysteresis. The distribution of softening-melting layers in the blast furnace known as the cohesive zone (CZ) is modelled by inserting solid blocks into the bed. The results indicate that the inverse-V cohesive zone shape leads to low powder accumulation within the CZ and at the corner of the bed. A mathematical model is proposed to describe gas-powder flow in a bed packed with particles. The model is the same as the two fluid model developed on the basis of the space-averaged theorem in terms of the governing equations but extended to consider the interactions between gas, powder and packed particles, as well as the static and dynamic holdups of powder. In particular, a method is proposed to determine the boundary between dynamic and stagnant zones with respect to powder phase, i.e. the profile of the powder accumulation zone. The validity of numerical modelling is examined by comparing the predicted and measured distributions of powder flow and accumulation under various flow conditions. With high PCI rate operations, a large quantity of unburned coal/char fines flow together with the gas into the blast furnace. Under some operating conditions, the holdup of fines results in deterioration of furnace permeability and lower production efficiency. Therefore, the proposed model is applied to simulate the powder (unburnt coal/char) flow and accumulation inside the blast furnace when operating with different cohesive zone (CZ) shapes. The results indicate that powder is likely to accumulate at the lower part of W-shaped CZs and the upper part of V- and inverse V-shaped CZs. In addition, for the same CZ shape, a thick cohesive layer can lead to a large pressure drop while the resistance of narrow cohesive layers to gas-powder flow is found to be relatively small. Gas-powder flow in moving beds of solid particles has been numerically investigated, under conditions related to the ironmaking blast furnace and high rate pulverized coal injection. A new correlation, which is formulated to describe static powder holdup in a moving packed bed, is incorporated into the previous mathematical model and applied to a description of gas-powder flow in a blast furnace. Compared with the results of fixed beds, the results show that the solids descent due to the consumption of ore, coke and unburnt char in various regions, together with the non-uniform structural distribution, significantly affects powder flow and accumulation in a blast furnace. Finally, liquid flow is simulated through force balance approach and numerical results are compared with the different liquid inlet distribution under the iron-making blast furnace conditions with gas flow. The results show that the effect of inlet distribution on liquid flow is significant in the upper part of coke region in BF and possible loading and dry zone can be numerically identified. Then, this part of work is incorporated to the developed gas-powder-solid modelling system to investigate the influence of liquid phase on other phases flow in the blast furnace although heat transfer and chemistry are not considered in the model.
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Zitoun, Khaled Bechir. "Continuous flow of solid-liquid food mixtures during ohmic heating : fluid interstitial velocities, solid area fraction, orientation and rotation /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu148794066543593.
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Zhang, Ming. "Optical measurement of ash particle size and velocity in gas-solid flow." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3462.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2004.<br>Title from document title page. Document formatted into pages; contains x, 98 p. : ill. (some col.) + 1 video file. Includes a video file (29 sec.). Includes abstract. Includes bibliographical references (p. 91-92).
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Zhang, Ning. "Motion and distribution of micro-sized solid particles in turbulent gas flow /." Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.
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Lu, Gang. "Rheological studies on the flow behavior of two-phase solid-liquid mate." [Ames, Iowa : Iowa State University], 2008.
Find full text
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Matta, Lawrence Mark. "Investigation of the flow turning loss in unstable solid propellant rocket motors." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15938.
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Zhang, Jiong. "Experimental and Numerical Investigations of Flow and Solid Transport in Urban Area." Phd thesis, INSA de Rennes, 2012. http://tel.archives-ouvertes.fr/tel-00764519.
Full textAbstract:
Dans la société moderne, l'aménagement du territoire peut augmenter la quantité d'eaux de ruissellement et sa charge de polluants associé. Plusieurs auteurs ont étudié des eaux de ruissellement transportant de la pollution dissoute, colloïdale et des composants solides de la ville. Un milieu poreux, tels que le sol, les roches, éponges, etc , est un matériau contenant un grand nombre de vides (pores) situées au hasard, de taille supérieure à l'échelle interatomiques. Les phénomènes de transport à l'interface entre un écoulement fluide et un milieu poreux font l'objet de recherches importantes à la fois pour comprendre les phénomènes d'infiltration dans le milieu poreux et aussi en raison de leur large champ d'application, par exemple en hydrologie urbaine, la pollution et dépollution des sols, le traitement de l'eau, etc. Comme dans l'hydrologie naturelle, l'hydrologie urbaine étudie l'érosion et les phénomènes de colmatage de la route qui causent beaucoup de pertes économiques et même menacent la vie des gens. Une meilleure compréhension des détails du flux de sédiments près de la surface de la route (milieu poreux) aidera à améliorer la conception des routes et à fournir des solutions optimisées. L'écoulement sur un milieu poreux combine une partie dessus et une partie à travers le milieu poreux. En raison de l'interaction entre l'écoulement de surface et d'infiltration à l'intérieur de la région poreuse, cette interaction affecte à la fois la le flux liquide et le flux de sédiments. L'effet de l'interaction entre le flux d'infiltration et l'écoulement de surface a été étudiée par plusieurs précurseurs qui ont développé soit un modèle microscopique soit un modèle macroscopique permettant une simulation numérique de l'écoulement turbulent dans la région poreuse. La plupart des études sur les flux en milieu poreux utilise des modèles macroscopiques en une ou deux dimensions (2D) lit poreux. Cependant en utilisant ces modèles il n'est pas possible d'avoir un aperçu détaillé de la structure de l'écoulement au voisinage de l'interface avec le milieu poreux. Ces dernières années, en raison du développement de la capacité de calcul, des simulation de mécanique des fluides numérique (CFD) complexe peuvent être effectuée. De plus, la méthode des éléments discrets (DEM), développé par Cundall et Strack, a été beaucoup utilisée pour étudier le comportement des solides granulaires soumis à une variété de conditions de chargement dans le but de comprendre et de prédire les résultats macroscopiques. Dans cette étude, les caractéristiques d'un écoulement à surface libre de faible profondeur, sur un lit poreux ainsi que le transport des sédiments induit sont étudiés tant numériquement que expérimentalement.
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Lang, Iain William Patterson. "Structure of flow in the freeboard region of gas/solid fluidised beds." Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/12387.
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Seo, Dongjin. "Measurement and Control of Slip-Flow Boundary Conditions at Solid-Gas Interfaces." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/50650.
Full textAbstract:
This thesis describes measurements of the gas-solid flow boundary condition at moderate Knudsen number, i.e., where the dimensions of the flow are similar to the mean free path, and thus partial slip is expected. This regime has become more important with increased focus on nano-scale devices, but there is currently no consensus on how the slip length should vary for different solids and gases, or whether it can be controlled. In this thesis, I describe unambiguous measurements showing that partial slip occurs, that the slip length depends both on gas and solid, and that the slip length can be altered in situ. The slip length is determined from analysis of the vibration of a small sphere adjacent to a solid. I also describe applications of these findings both to the separation of gases, and to inhalants.
The effect of water films, gas species, organic films, and electric fields on gas flow was studied. Water films had a large, but complex effect. On bare hydrophobilic glass, the tangential momentum accommodation coefficient (TMAC) for nitrogen on hydroxyl-terminated silica changed from 0.25 to 0.88 when the humidity changed from 0 to 98 %. On hydrophobized glass, TMAC changed from 0.20 to 0.56 in the same range.
The effect of the gas on TMAC was measured for five different gases (helium, nitrogen, argon, carbon dioxide, hexafluoride sulfur) on octadecyltrichlorosilane-coated glass surfaces. A lower
TMAC occurred for greater molar mass, and this trend was explained using a simple model representing both the gas and the monolayer by spheres. The existence of this gas-dependent difference in TMAC suggests that gases can be separated based on their collisions with surfaces.
Methods for controlling the flow boundary condition were also developed by adsorbing monolayers on the solid, and altering the monolayers in situ. Both temperature and electric fields altered the boundary condition, and these changes were attributed to changes in the surface roughness. The effect of roughness was modeled with grooved surfaces. Possible applications of this effect of roughness include changing the flow of aerosol droplets for deeper delivery of therapeutic drugs into the lung.<br>Ph. D.
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Wredh, Simon. "Neural Network Based Model Predictive Control of Turbulent Gas-Solid Corner Flow." Thesis, Uppsala universitet, Signaler och system, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-420056.
Full textAbstract:
Over the past decades, attention has been brought to the importance of indoor air quality and the serious threat of bio-aerosol contamination towards human health. A novel idea to transport hazardous particles away from sensitive areas is to automatically control bio-aerosol concentrations, by utilising airflows from ventilation systems. Regarding this, computational fluid dynamics (CFD) may be employed to investigate the dynamical behaviour of airborne particles, and data-driven methods may be used to estimate and control the complex flow simulations. This thesis presents a methodology for machine-learning based control of particle concentrations in turbulent gas-solid flow. The aim is to reduce concentration levels at a 90 degree corner, through systematic manipulation of underlying two-phase flow dynamics, where an energy constrained inlet airflow rate is used as control variable. A CFD experiment of turbulent gas-solid flow in a two-dimensional corner geometry is simulated using the SST k-omega turbulence model for the gas phase, and drag force based discrete random walk for the solid phase. Validation of the two-phase methodology is performed against a backwards facing step experiment, with a 12.2% error correspondence in maximum negative particle velocity downstream the step. Based on simulation data from the CFD experiment, a linear auto-regressive with exogenous inputs (ARX) model and a non-linear ARX based neural network (NN) is used to identify the temporal relationship between inlet flow rate and corner particle concentration. The results suggest that NN is the preferred approach for output predictions of the two-phase system, with roughly four times higher simulation accuracy compared to ARX. The identified NN model is used in a model predictive control (MPC) framework with linearisation in each time step. It is found that the output concentration can be minimised together with the input energy consumption, by means of tracking specified target trajectories. Control signals from NN-MPC also show good performance in controlling the full CFD model, with improved particle removal capabilities, compared to randomly generated signals. In terms of maximal reduction of particle concentration, the NN-MPC scheme is however outperformed by a manually constructed sine signal. In conclusion, CFD based NN-MPC is a feasible methodology for efficient reduction of particle concentrations in a corner area; particularly, a novel application for removal of indoor bio-aerosols is presented. More generally, the results show that NN-MPC may be a promising approach to turbulent multi-phase flow control.
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Ferkul, Paul Vincent. "A model of concurrent flow flame spread over a thin solid fuel." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1056655244.
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Khan, Mohammad Younis. "The mechanisms of plastic flow in semi-plastic crystals under the hardness indentation." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279911.
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Xie, Cheng-Gang. "Mass flow measurement of solids in a gravity drop conveyor using capacitance transducers." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254465.
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Wu, Shimin Materials Science & Engineering Faculty of Science UNSW. "Model studies of solid flow and size segregation in packed and moving beds." Awarded by:University of New South Wales. Materials Science & Engineering, 2007. http://handle.unsw.edu.au/1959.4/40565.
Full textAbstract:
This work examines the fundamental behaviour of granular materials in packed/moving beds under simplified blast furnace conditions. Such study has a significant impact on the development of new technology such as pulverized coal injection and the performance of blast furnace operation. Experiments have shown that a number of interesting phenomena appear in blast furnace operation. These phenomena involve rich granular dynamics which currently attract strong interest from a wide scientific and engineering. However, previous work on this area, limited by the research techniques, is predominantly at large scales focusing on phenomenological descriptions, but rarely touching on the basic fundamentals governing these phenomena. A novel discrete element simulation at an individual particle level can overcome these problems. For this purpose, this work conducts a systematic study of these important phenomena, including crater formation, coke collapse, creep motion and particle percolation, by use of the discrete element method (DEM). The experiments and simulations conducted in the impact of a particle stream onto a particle bed using a 20 slot model suggest that the DEM can reproduce the experimental results well under comparative conditions. The crater size is shown to be affected by the discharging rate, discharging height and materials properties, and is related to the ratio of the input energy from the falling stream to the inertial energy from the original packing. Fundamental understanding of coke collapse based on three different configurations: batch charging, self loading and load impact have been investigated. It was found that coke collapse is a kind of continuous avalanche due to top layer particles spreading. Apparent frozen layer under rapidly flowing layer is not stationary and slowly creep motion can be detected at an arbitrary depth. The mean velocity of creep motion decays exponentially with depth. Percolation happens due to both gravity and strain. The percolation velocity under gravity is much greater than that under shear. Size ratio effect is most significant. For size ratio smaller than threshold gravity induced percolation dominate otherwise shear due to the descending of the packed bed. Additionally, this work demonstrates the value of DEM as a tool for complementing experimental observations.