What Happens To Nox Emissions Of Vw Diesel Cars When Water/Methanol Injection Is Used?, 2017 Southern Illinois University Carbondale
What Happens To Nox Emissions Of Vw Diesel Cars When Water/Methanol Injection Is Used?, Andrew Croxell
ASA Multidisciplinary Research Symposium
Volkswagen has come under fire for their "Clean Diesel" automobiles that were found to emit too much NOx (Oxides of Nitrogen) when driven on the street. Since NOx is created by high temperature combustion events, the addition of a water/methanol injection system was tested on a VW diesel vehicle to identify if it could cool combustion temperatures and thus reduce NOx to an acceptable specification.
Hydrodynamics In The Gas-Driven Inverse Liquid-Solid Fluidized Bed, 2017 The University of Western Ontario
Hydrodynamics In The Gas-Driven Inverse Liquid-Solid Fluidized Bed, Jiaqi Huang
Electronic Thesis and Dissertation Repository
A novel reactor named Gas-Driven Inverse Liquid-Solid Fluidized Bed (GDFB for short) was developed in this research. A vertical baffle divides the column into a riser and a downer. Inverse fluidization is driven by the gas and occurs in the downer, where hydrodynamics and their influencing factors were studied. In the solid-baffle system, four fluidization regimes were observed, including the packed bed, semi-fluidized bed, fully-fluidized bed, and circulating bed. Bed expansion ratio was higher for particles with a higher density and a smaller solids loading. Moreover, the average particle velocity was proportional to superficial gas velocity and higher for denser ...
Kinetics Of Glycerol Conversion To Hydrocarbon Fuels Over Pd/H-Zsm-5 Catalyst, 2017 Purdue University
Kinetics Of Glycerol Conversion To Hydrocarbon Fuels Over Pd/H-Zsm-5 Catalyst, Yang Xiao, Arvind Varma
Modeling The Aqueous-Phase Copper Ion-Exchange Behavior Onto Ssz-13 Zeolites, 2017 Purdue University
Modeling The Aqueous-Phase Copper Ion-Exchange Behavior Onto Ssz-13 Zeolites, Brian N. Bayer, Rajamani Gounder, Trevor M. Lardinois
The Summer Undergraduate Research Fellowship (SURF) Symposium
Copper-exchanged zeolites are utilized as catalysts for the selective catalytic reduction of nitrogen oxides, which are atmospheric pollutants found in diesel engine exhaust. The total amount of copper ions and the types of copper species (Cu(II) or Cu(II)OH) exchanged onto a zeolite can be varied. Copper is exchanged onto SSZ-13 (an aluminosilicate zeolite with the chabazite topology) during a process known as aqueous ion exchange, where the zeolite is mixed in a copper-containing solution. The distribution of copper on SSZ-13 is influenced by exchange conditions, including the molarity, temperature, and pH of the copper solution. The effect ...
Turbulent Combustion Of Polydisperse Evaporating Sprays With Droplet Crossing: Eulerian Modeling And Validation In The Infinite Knudsen Limit, S. De Chaisemartin, L. Freret, D. Kah, F. Laurent, Rodney O. Fox, J. Reveillon, M. Massot
Rodney O. Fox
The accurate simulation of the dynamics of polydisperse evaporating sprays in unsteady gaseous flows with large-scale vortical structures is both a crucial issue for industrial applications and a challenge for modeling and scientific computing. The difficulties encountered by the usual Lagrangian approaches make the use of Eulerian models attractive, aiming at a lower cost and an easier coupling with the carrier gaseous phase. Among these models, the multi-fluid model allows for a detailed description of the polydispersity and size-velocity correlations for droplets of various sizes. The purpose of the present study is twofold. First, we extend the multi-fluid model in ...
Consistent Hybrid Les-Fdf Formulation For The Simulation Of Turbulent Combustion, 2017 Iowa State University
Consistent Hybrid Les-Fdf Formulation For The Simulation Of Turbulent Combustion, Venkatramanan Raman, H. Pitsch, Rodney O. Fox
Rodney O. Fox
The numerical simulation of turbulent reactive flows is a complex and challenging problem with widespread practical use. Recent breakthroughs in algorithmic techniques and the drastic increase in computing power have provided us with the tools to understand the complex interaction between turbulence and chemical reactions. In the past decade, the use of the large-eddy simulation (LES) technique has made it possible to make accurate predictions of turbulent flows even for complex configurations.
Modeling Fluidization In Biomass Gasification Processes, 2017 Iowa State University
Modeling Fluidization In Biomass Gasification Processes, Emmanuela Gavi, Theodore J. Heindel, Rodney O. Fox
Rodney O. Fox
Extensive validation of computational fluid dynamics (CFD) models is required when modeling biomass fluidization, because several required model inputs are not know or not easily measured experimentally for biomass. In the present work, CFD fluidization modeling of a biomass bed is validated by comparison with X-ray computed tomography experimental data. A parametric study was carried out by employing ground walnut shell or ground corncob as model biomass bed materials, and fluidization was performed at a gas velocity twice the minimum fluidization velocity. An important result is the use of an "effective density" for biomass in the CFD model, the use ...
Numerical Simulations Of Turbulent Bluff-Body Flames Using Multi-Environment Presumed Pdf Method With Realistic Chemistry, 2017 Reaction Engineering International
Numerical Simulations Of Turbulent Bluff-Body Flames Using Multi-Environment Presumed Pdf Method With Realistic Chemistry, Qing Tang, Wei Zhao, Micahel Bockelie, Rodney O. Fox
Rodney O. Fox
A Computational Fluid Dynamics (CFD) tool for performing turbulent combustion simulations that require finite rate chemistry is developed and tested by modeling a series of bluff-body stabilized flames that exhibit different levels of finite-rate chemistry effects ranging from near equilibrium to near global extinction. The new modeling tool is based on the multi-environment probability density function (MEPDF) methodology and combines the following: the direct quadrature method of moments (DQMOM); the interaction-by-exchange-with-the-mean (IEM) mixing model; and realistic combustion chemistry. A pseudo time splitting scheme is adopted to solve the MEPDF equations; the reaction source terms are computed with a highly efficient ...
Numerical Description Of Dilute Particle-Laden Flows By A Quadrature-Based Moment Method, 2017 Office National d'Etudes et de Recherches Aerospatiales, France
Numerical Description Of Dilute Particle-Laden Flows By A Quadrature-Based Moment Method, N. Le Lostec, Rodney O. Fox, O. Simonin, P. Villedieu
Rodney O. Fox
The numerical simulation of gas-particle flows is divided into two families of methods. In Euler-Lagrange methods individual particle trajectories are computed, whereas in Euler-Euler methods particles are characterized by statistical descriptors. Lagrangian methods are very precise but their computational cost increases with instationarity and particle volume fraction. In Eulerian methods (also called moment methods) the particle-phase computational cost is comparable to that of the fluid phase but requires strong simplificaions. Existing Eulerian models consider unimodal or close-to-equilibrium particle velocity distributions and then fail when the actual distribution is far from equilibrium. Quadrature-based Eulerian methods introduce a new reconstruction of the ...
Conditional-Moment Closure With Differential Diffusion For Soot Evolution In Fire, 2017 Sandia National Laboratories
Conditional-Moment Closure With Differential Diffusion For Soot Evolution In Fire, J. C. Hewson, A. J. Ricks, S. R. Tieszen, A R. Kerstein, Rodney O. Fox
Rodney O. Fox
The conditional-moment closure (CMC) equation for the evolution of a large Lewis number scalar, soot, is derived starting from the joint probability density function (pdf) equation for the gas-phase mixture fraction, ξ g , and the soot mass fraction, Y s . Unlike previous approaches starting with the joint pdf, the residual terms that result from the typical closure models were retained. A new formulation of the one-dimensional turbulence (ODT) model suitable for spatially evolving flows with buoyant acceleration and radiative transport in participating media was employed to carry out simulations of a prototypical ethene fire. The resulting ODT evolution of ξ ...
A Quadrature-Based Moment Closure For The Williams Spray Equation, 2017 Iowa State University
A Quadrature-Based Moment Closure For The Williams Spray Equation, O. Desjardins, Rodney O. Fox, P. Villedieu
Rodney O. Fox
Sprays and other dispersed-phase systems can be described by a kinetic equation containing terms for spatial transport, acceleration, and particle processes (such as evaporation or collisions). In principle, the kinetic description is valid from the dilute (non-collisional) to the dense limit. However, its numerical solution in multi-dimensional systems is intractable due to the large number of independent variables. As an alternative, Lagrangian methods "discretize" the density function into "parcels" that are simulated using Monte-Carlo methods. While quite accurate, as in any statistical approach, Lagrangian methods require a relatively large number of parcels to control statistical noise, and thus are computationally ...
Development Of High-Order Realizable Finite-Volume Schemes For Quadrature-Based Moment Method, 2017 Iowa State University
Development Of High-Order Realizable Finite-Volume Schemes For Quadrature-Based Moment Method, Varun Vikas, Z. J. Wang, Alberto Passalacqua, Rodney O. Fox
Rodney O. Fox
Kinetic equations containing terms for spatial transport, gravity, fluid drag and particle-particle collisions can be used to model dilute gas-particle flows. However, the enormity of independent variables makes direct numerical simulation of these equations almost impossible for practical problems. A viable alternative is to reformulate the problem in terms of moments of velocity distribution. Recently, a quadrature-based moment method was derived by Fox for approximating solutions to kinetic equation for arbitrary Knudsen number. Fox also described 1st- and 2nd-order finite-volume schemes for solving the equations. The success of the new method is based on a moment-inversion algorithm that is used ...
Instantaneous Particle Acceleration Model For Gas-Solid Suspensions At Moderate Reynolds Numbers, 2017 Iowa State University
Instantaneous Particle Acceleration Model For Gas-Solid Suspensions At Moderate Reynolds Numbers, Sudheer Tenneti, Rodney O. Fox, Shankar Subramaniam
Rodney O. Fox
Gas-solid flows are encountered in many industrial applications such as fluidized beds and coal gasification. The design and scale-up of such industrial devices required a better understanding of the characteristics of gas-solid suspensions. Device-scale computational fluid dynamics (CFD) simulations that solve for average quantities such as solid volume fraction and phasic mean velocity fields are being extensively used in the industrial design process. The capability of the simulations to accurately predict the characteristics of gas-solid flow depends upon the accuracy of the models for unclosed terms that appear in the equations for mass, momentum and energy conservation. Hrenya and Sinclair ...
A Fully Coupled Fluid-Particle Flow Solver Using Quadrature-Based Moment Method With High-Order Realizable Schemes On Unstructured Grids, Varun Vikas, Z. J. Wang, Alberto Passalacqua, Rodney O. Fox
Rodney O. Fox
Kinetic Equations containing terms for spatial transport, gravity, fluid drag and particle-particle collisions can be used to model dilute gas-particle flows. However, the enormity of independent variables makes direct numerical simulation of these equations almost impossible for practical problems. A viable alternative is to reformulate the problem in terms of moments of the velocity distribution function. A quadrature method of moments (QMOM) was derived by Desjardins et al.  for approximating solutions to the kinetic equation for arbitrary Knudsen number. Fox [2, 13] derived a third-order QMOMfor dilute particle flows, including the effect of the fluid drag on the particles ...
Numerical Simulation Of Turbulent Gas-Particle Flow In A Riser Using A Quadrature-Based Moment Method, 2017 Iowa State University
Numerical Simulation Of Turbulent Gas-Particle Flow In A Riser Using A Quadrature-Based Moment Method, Alberto Passalacqua, Rodney O. Fox
Rodney O. Fox
Gas-particle flows are used in many industrial applications in the energy, oil and gas fields, such as coal gasification, production of light hydrocarbons by fluid catalytic cracking, catalytic combustion and different treatments aiming to reduce or eliminate pollutants. The particle phase of a gas-particle flow is described by analogy to a granular gas, by finding an approximate solution of the kinetic equation in the velocity-based number density function. In the recent past, many studies have been published on the mathematical modeling of gas-particle flows using hydrodynamic models (e.g. Enwald et al. 1996), where Navier-Stokes-type equations are solved to describe ...
Acetone Production, 2017 Western Michigan University
Acetone Production, Ali Ibrahim Neamah
The Hilltop Review
Iraq struggles with a lack of acetone production. This overall deficiency impacts the economy of countries like Iraq. Inasmuch, acetone is a vital chemical component for many items imported into this country such as nail polish remover. Therefore, a process of acetone production is proposed in this study.
The ideal process of producing acetone with 90.0% isopropyl alcohol (IPA) decomposition method is proposed within this study. The feed of the process is 100000 ton/ day. This amount of feed is suggested due to the demographic need of acetone for the Iraqi population as well as the surrounding Middle Eastern ...
The Dry Reforming Of Methane To Syngas And Subsequent Products, 2017 University of Wyoming
The Dry Reforming Of Methane To Syngas And Subsequent Products, Sean Kasprisin 4347974, Timothy Poppert, Nykyta Vovk, Alexander Fox, Hussain Alsukairi
Honors Theses AY 16/17
Dry Reforming of Methane to Syngas other Subsequent Products
Hussain Alsukairi, Alexander Fox, Sean Kasprisin, Tim Poppert, Nykta Vovk
University of Wyoming
Synthesis Gas, or syngas (a combination of Hydrogen and Carbon Monoxide) can be used in a plethora of different chemical processes and processing plants. Utilizing Steam reforming of methane has been the accepted method to create syngas and it utilized on an industrial scale. Steam reforming of methane results in the formation of Carbon Dioxide (a greenhouse gas) that has to be dealt with so the impact on the environment can be minimized. Dry-reforming ...
Methanol Steam Reforming: Na Doping Of Pt/Ysz Provides Fine Tuning Of Selectivity, 2017 University of Kentucky
Methanol Steam Reforming: Na Doping Of Pt/Ysz Provides Fine Tuning Of Selectivity, Michela Martinelli, Gary Jacobs, Uschi M. Graham, Burtron H. Davis
Center for Applied Energy Research Faculty Publications
In this work, we found that sodium doping can be used to improve CO2 selectivity for supported Pt catalyst during methanol steam reforming. These materials are usually very active in the low temperature range; however, they are characterized by high selectivity of CO, which is a poison in downstream polymer electrolyte membrane fuel cells (PEM-FC) application. With Na doping, we found that CO2 selectivity was higher than 90% when 2.5 wt.% of sodium was added to Pt/YSZ. We have speculated that the different product distribution is due to a different reaction pathway being opened for CH ...
Catalytic Hydrodeoxygenation And Dehydration Of Bioderived Oxygenates To Renewable Hydrocarbon Building Block Molecules: Enabling Renewable Carbon Fiber, 2017 University of Tennessee, Knoxville
Catalytic Hydrodeoxygenation And Dehydration Of Bioderived Oxygenates To Renewable Hydrocarbon Building Block Molecules: Enabling Renewable Carbon Fiber, Andrew Walter Lepore
It is our goal to develop inexpensive catalytic pathways that can effectively remove oxygen from bio-derived carboxylic acids and alcohols under mild reaction conditions to produce propene which can be converted to renewable carbon fibers. Carboxylic acid hydrodeoxygenation and alcohol dehydration are necessary for successfully producing propene from bio-mass derived precursors and are also broadly relevant to bio-oil upgrading. This body of research adds to the understanding of both known and novel catalyst materials and develops and optimizes pathways for valorizing oxygenates. Dehydration and hydrodeoxygenation catalysts were examined under both batch and continuous flow operation. Product selectivity and reactant conversion ...
Photoactive Properties Of Nanostructured Titania Modified Polyurethanes, 2017 The University of Western Ontario
Photoactive Properties Of Nanostructured Titania Modified Polyurethanes, Chao Chen
Electronic Thesis and Dissertation Repository
In order to enhance both the photoactivity and physical/mechanical properties of titania/polyurethane (PU) nanocomposites, in-situ polymerization and film casting were investigated. Both self-degrading PU foams and self-cleaning PU coatings were prepared. Functional monomers were prepared usingDMPA (2,2-dimethylolpropionic acid) functionalized anatse TiO2 and P25 for integration into polyurethane foam with a "grafting-from" synthetic method. This technique was found to successfully reduce the agglomeration effect of titania nanoparticles inside the foams. In addition, the photodegradation rate was enhanced by > 120% over unmodified foam at an optimized loading of 3wt% DMPA functionalized anatase TiO2. The presence of DMPA ...