A Quadrature-Based Moment Method For Polydisperse Bubbly Flows, 2019 Iowa State University and Ames Laboratory

#### A Quadrature-Based Moment Method For Polydisperse Bubbly Flows, Jeffrey C. Heylmun, Bo Kong, Alberto Passalacqua, Rodney O. Fox

*Alberto Passalacqua*

A computational algorithm for polydisperse bubbly flow is developed by combining quadrature-based moment methods (QBMM) with an existing two-fluid solver for gas–liquid flows. Care is taken to ensure that the two-fluid model equations are hyperbolic by generalizing the kinetic model for the bubble phase proposed by Bieseuvel and Gorissen (1990). The kinetic formulation for the bubble phase includes the full suite of interphase momentum exchange terms for bubbly flow, as well as ad hoc bubble–bubble interaction terms to model the transition from isolated bubbles to regions of pure air at very high bubble-phase volume fractions. A robust numerical ...

A Quadrature-Based Moment Method For Polydisperse Bubbly Flows, 2019 Iowa State University and Ames Laboratory

#### A Quadrature-Based Moment Method For Polydisperse Bubbly Flows, Jeffrey C. Heylmun, Bo Kong, Alberto Passalacqua, Rodney O. Fox

*Rodney O. Fox*

A computational algorithm for polydisperse bubbly flow is developed by combining quadrature-based moment methods (QBMM) with an existing two-fluid solver for gas–liquid flows. Care is taken to ensure that the two-fluid model equations are hyperbolic by generalizing the kinetic model for the bubble phase proposed by Bieseuvel and Gorissen (1990). The kinetic formulation for the bubble phase includes the full suite of interphase momentum exchange terms for bubbly flow, as well as ad hoc bubble–bubble interaction terms to model the transition from isolated bubbles to regions of pure air at very high bubble-phase volume fractions. A robust numerical ...

A Quadrature-Based Moment Method For Polydisperse Bubbly Flows, 2019 Iowa State University and Ames Laboratory

#### A Quadrature-Based Moment Method For Polydisperse Bubbly Flows, Jeffrey C. Heylmun, Bo Kong, Alberto Passalacqua, Rodney O. Fox

*Chemical and Biological Engineering Publications*

A computational algorithm for polydisperse bubbly flow is developed by combining quadrature-based moment methods (QBMM) with an existing two-fluid solver for gas–liquid flows. Care is taken to ensure that the two-fluid model equations are hyperbolic by generalizing the kinetic model for the bubble phase proposed by Bieseuvel and Gorissen (1990). The kinetic formulation for the bubble phase includes the full suite of interphase momentum exchange terms for bubbly flow, as well as ad hoc bubble–bubble interaction terms to model the transition from isolated bubbles to regions of pure air at very high bubble-phase volume fractions. A robust numerical ...

Investigation And Modeling Of The Dip Coating For Dispersions With Near Wall Effects, 2019 The University of Western Ontario

#### Investigation And Modeling Of The Dip Coating For Dispersions With Near Wall Effects, Mahdieh Moghadasi

*Electronic Thesis and Dissertation Repository*

The key to controlling the quality of liquid dispersion coated films lies in the particle distribution in the flow field. The control of particle dispersion in the film can also empower the optimization of the process operation. Therefore, a numerical simulation of a solid-liquid suspension in the dip coating (free withdrawal) process using the finite element method for the fluid flow has been developed. The neutrally buoyant suspension is considered as a Newtonian fluid with a concentration-dependent viscosity. A continuum constitutive equation is employed based on the diffusive flux model in twodimensional flow. The main purpose of this study is ...

A Lagrangian Probability-Density-Function Model For Collisional Turbulent Fluid–Particle Flows, 2019 Sorbonne Universite and Universita di Pisa

#### A Lagrangian Probability-Density-Function Model For Collisional Turbulent Fluid–Particle Flows, Alessio Innocenti, Rodney O. Fox, Maria Vittoria Salvetti, Sergio Chibbaro

*Chemical and Biological Engineering Publications*

Inertial particles in turbulent flows are characterised by preferential concentration and segregation and, at sufficient mass loading, dense particle clusters may spontaneously arise due to momentum coupling between the phases. These clusters, in turn, can generate and sustain turbulence in the fluid phase, which we refer to as cluster-induced turbulence (CIT). In the present work, we tackle the problem of developing a framework for the stochastic modelling of moderately dense particle-laden flows, based on a Lagrangian probability-density-function formalism. This framework includes the Eulerian approach, and hence can be useful also for the development of two-fluid models. A rigorous formalism and ...

Call For Abstracts - Resrb 2019, July 8-9, Wrocław, Poland, 2018 Wojciech Budzianowski Consulting Services

#### Call For Abstracts - Resrb 2019, July 8-9, Wrocław, Poland, Wojciech M. Budzianowski

*Wojciech Budzianowski*

No abstract provided.

Effect Of Density Ratio On Velocity Fluctuations In Dispersed Multiphase Flow From Simulations Of Finite-Size Particles, 2018 Iowa State University

#### Effect Of Density Ratio On Velocity Fluctuations In Dispersed Multiphase Flow From Simulations Of Finite-Size Particles, Vahid Tavanashad, Alberto Passalacqua, Rodney O. Fox, Shankar Subramaniam

*Chemical and Biological Engineering Publications*

Velocity fluctuations in the carrier phase and dispersed phase of a dispersed multiphase flow are studied using particle-resolved direct numerical simulation. The simulations correspond to a statistically homogeneous problem with an imposed mean pressure gradient and are presented for Rem=20 and a wide range of dispersed phase volume fractions (0.1≤ϕ≤0.4) and density ratios of the dispersed phase to the carrier phase (0.001≤ρp/ρf≤1000) . The velocity fluctuations in the fluid and dispersed phase at the statistically stationary state are quantified by the turbulent kinetic energy (TKE) and granular temperature, respectively. It is found ...

Hydrodynamics Of A Gas-Driven Gas-Liquid-Solid Spouted Bed, 2018 The University of Western Ontario

#### Hydrodynamics Of A Gas-Driven Gas-Liquid-Solid Spouted Bed, Jia Meng

*Electronic Thesis and Dissertation Repository*

A novel cylindrical gas-driven gas-liquid-solid spouted bed was developed in this project, which has a high potential to be used for a biological wastewater treatment process. Solids motion, flow regimes, and regime transitions in this system were studied. With increasing gas velocity, four regimes were identified, including: fixed bed, semi spouted bed, full spouted bed and internal circulating fluidized bed. The respective gas velocities for the transitions between the four regimes were experimentally identified and termed as minimum spouting velocity, full spouting velocity and minimum circulating velocity. A new “basketing” method was adopted to measure the minimum spouting velocity while ...

Bubble Dynamics And Dense Phase Composition In 2-D Binary Gas-Solid Fluidized Bed, 2018 The University of Western Ontario

#### Bubble Dynamics And Dense Phase Composition In 2-D Binary Gas-Solid Fluidized Bed, Tianzi Bai

*Electronic Thesis and Dissertation Repository*

Gas-solid bubbling fluidized bed with binary particles is a potential candidate for performing the dry coal beneficiation process due to its advantages such as the ability to adjust separation density and the elimination of process water. A two-dimensional (2D) fluidized bed was used to study bubble dynamics and dense phase composition distribution in order to gain some fundamental understanding of this system. Digital image analysis (DIA) was employed to measure bubble diameter, bubble rise velocity, bed expansion and particle composition distribution. Magnetite and sand particles as pure and binary mixtures were used in the fluidized bed. Bubble diameter and bubble ...

On The Transition Between Turbulence Regimes In Particle-Laden Channel Flows, 2018 University of Michigan

#### On The Transition Between Turbulence Regimes In Particle-Laden Channel Flows, Jesse Capecelatro, Olivier Desjardins, Rodney O. Fox

*Chemical and Biological Engineering Publications*

Turbulent wall-bounded flows exhibit a wide range of regimes with significant interaction between scales. The fluid dynamics associated with single-phase channel flows is predominantly characterized by the Reynolds number. Meanwhile, vastly different behaviour exists in particle-laden channel flows, even at a fixed Reynolds number. Vertical turbulent channel flows seeded with a low concentration of inertial particles are known to exhibit segregation in the particle distribution without significant modification to the underlying turbulent kinetic energy (TKE). At moderate (but still low) concentrations, enhancement or attenuation of fluid-phase TKE results from increased dissipation and wakes past individual particles. Recent studies have shown ...

An Open-Source Quadrature-Based Population Balance Solver For Openfoam, 2018 Iowa State University

#### An Open-Source Quadrature-Based Population Balance Solver For Openfoam, Alberto Passalacqua, Frédérique Laurent, Ehsan Madadi-Kandjani, Jeffrey C. Heylmun, Rodney O. Fox

*Rodney O. Fox*

The extended quadrature method of moments (EQMOM) for the solution of population balance equations (PBE) is implemented in the open-source computational fluid dynamic (CFD) toolbox OpenFOAM as part of the OpenQBMM project. The moment inversion procedure was designed (Nguyen et al., 2016) to maximize the number of conserved moments in the transported moment set. The algorithm is implemented in a general structure to allow the addition of other kernel density functions defined on R+, and arbitrary kernels to describe physical phenomena involved in the evolution of the number density function. The implementation is verified with a set of zero-dimensional cases ...

On The Transition Between Turbulence Regimes In Particle-Laden Channel Flows, 2018 University of Michigan

#### On The Transition Between Turbulence Regimes In Particle-Laden Channel Flows, Jesse Capecelatro, Olivier Desjardins, Rodney O. Fox

*Rodney O. Fox*

Turbulent wall-bounded flows exhibit a wide range of regimes with significant interaction between scales. The fluid dynamics associated with single-phase channel flows is predominantly characterized by the Reynolds number. Meanwhile, vastly different behaviour exists in particle-laden channel flows, even at a fixed Reynolds number. Vertical turbulent channel flows seeded with a low concentration of inertial particles are known to exhibit segregation in the particle distribution without significant modification to the underlying turbulent kinetic energy (TKE). At moderate (but still low) concentrations, enhancement or attenuation of fluid-phase TKE results from increased dissipation and wakes past individual particles. Recent studies have shown ...

On The Hyperbolicity Of The Two-Fluid Model For Gas–Liquid Bubbly Flows, 2018 Iowa State University

#### On The Hyperbolicity Of The Two-Fluid Model For Gas–Liquid Bubbly Flows, Nithin Panicker, Alberto Passalacqua, Rodney O. Fox

*Chemical and Biological Engineering Publications*

The hyperbolicity condition of the system of partial differential equations (PDEs) of the incompressible two-fluid model, applied to gas–liquid flows, is investigated. It is shown that the addition of a dispersion term, which depends on the drag coefficient and the gradient of the gas volume fraction, ensures the hyperbolicity of the PDEs, and prevents the nonphysical onset of instabilities in the predicted multiphase flows upon grid refinement. A constraint to be satisfied by the coefficient of the dispersion term to ensure hyperbolicity is obtained. The effect of the dispersion term on the numerical solution and on its grid convergence ...

Development Of Microdialysis Probes In Series Approach Toward Eliminating Microdialysis Sampling Calibration: Miniaturization Into A Pdms Microfluidic Device, 2018 University of Arkansas, Fayetteville

#### Development Of Microdialysis Probes In Series Approach Toward Eliminating Microdialysis Sampling Calibration: Miniaturization Into A Pdms Microfluidic Device, Randy Espinal Cabrera

*Theses and Dissertations*

A new microdialysis sampling method and microfluidic device were developed in vitro. The method consisted of using up to four microdialysis sampling probes connected in series to evaluate the relative recovery (RR) of different model solutes methyl orange, fluorescein isothiocyanate (FITC)-dextran average mol. wt. 4,000 (FITC-4), FITC-10, FITC-20, and FITC-40. Different flow rates (0.8, 1.0, and 1.5 µL/min) were used to compare experimentally observed relative recoveries with theoretical estimations. With increasing the number of probes in series, the relative recovery increases and ~100% (99.7% ± 0.9%) relative recovery for methyl orange was obtained ...

Mobility Of Nano-Particles In Rock Based Micro-Models, 2018 Louisiana State University and Agricultural and Mechanical College

#### Mobility Of Nano-Particles In Rock Based Micro-Models, Jagannath Upadhyay

*LSU Doctoral Dissertations*

A confocal micro-particle image velocimetry (C-μPIV) technique along with associated post-processing algorithms is detailed for obtaining three dimensional distributions of nano-particle velocity and concentrations at select locations of the 2.5D (pseudo 3D) Poly(methyl methacrylate) (PMMA) and ceramic micro-model. The designed and fabricated 2.5D micro-model incorporates microchannel networks with 3D wall structures with one at observation wall which resembles fourteen morphological and flow parameters to those of fully 3D actual reservoir rock (Boise Sandstone) at resolutions of 5 and 10 μm in depth and 5 and 25 μm on plane. In addition, an in-situ, non-destructive method for measuring ...

Multicomponent Working Fluids In Organic Rankine Cycle Evaporators, 2018 Union College

#### Multicomponent Working Fluids In Organic Rankine Cycle Evaporators, Jennifer Fromm

*Honors Theses*

Organic Rankine cycles are a promising technology to convert waste heat energy into usable mechanical or electric power, giving them the potential to reduce fossil fuel emissions generated by traditional energy generation. The heat exchangers of these devices are of particular interest, as maximizing energy extraction from these free heat sources will increase net electrical power output. For this project I created a model to predict the effects of mixture working fluids on the evaporator performance of an organic Rankine cycle generator for a wide range of waste heat source temperatures. This model combines empirically derived heat exchanger performance parameters ...

An Open-Source Quadrature-Based Population Balance Solver For Openfoam, 2018 Iowa State University

#### An Open-Source Quadrature-Based Population Balance Solver For Openfoam, Alberto Passalacqua, Frédérique Laurent, Ehsan Madadi-Kandjani, Jeffrey C. Heylmun, Rodney O. Fox

*Chemical and Biological Engineering Publications*

The extended quadrature method of moments (EQMOM) for the solution of population balance equations (PBE) is implemented in the open-source computational fluid dynamic (CFD) toolbox OpenFOAM as part of the OpenQBMM project. The moment inversion procedure was designed (Nguyen et al., 2016) to maximize the number of conserved moments in the transported moment set. The algorithm is implemented in a general structure to allow the addition of other kernel density functions defined on R+, and arbitrary kernels to describe physical phenomena involved in the evolution of the number density function. The implementation is verified with a set of zero-dimensional cases ...

Effects Of Hofmeister Ions On Gelation Of Gelatin And Pluronic Hydrogels, 2018 The University of Akron

#### Effects Of Hofmeister Ions On Gelation Of Gelatin And Pluronic Hydrogels, Eric Britton

*Williams Honors College, Honors Research Projects*

The purpose of the project was to observe the effects of the Hofmeister series of ions on the gelation of gelatin and Pluronic-127 hydrogels. Hydrogels are semi-solid materials that contain a network of joined molecules through intermolecular interactions which are capable of holding water. Gelatin and Pluronic-127 (PF-127) are thermoreversible, physical crosslinked gels. Gelation occurs when temperature, or other driving forces, reduce the polymer chain solubility until a distinct 2-phase system forms. When aqueous ions are present in solution, they exhibit specific ion effects that have either a stabilizing or destabilizing effect on the solubility of proteins and other polymers ...

Modeling The Effect Thickener Structure Has On The Oil Release Of Grease, 2018 The University of Akron

#### Modeling The Effect Thickener Structure Has On The Oil Release Of Grease, Dana Cressman

*Williams Honors College, Honors Research Projects*

Our hypothesis was that the thickener type and micelle concentration of grease affected its viscoelastic properties. Measurements were made using a TA AR G2 rheometer and calculations were made using TA rheometer analysis software to characterize the viscoelastic response of grease under oscillatory shear and frequency tests. The oscillatory frequency tests determined the critical micelle concentration. The oscillatory stress tests were taken at temperatures from 5 to 65 degrees Celsius to create a master curve based on time temperature superposition of the measurements. The crossover points of G’ and G” on the oscillatory stress tests demonstrated where the grease transitions ...

Rheological Properties Of A Model Soft Solid Nanocomposite, 2018 University of Massachusetts Amherst

#### Rheological Properties Of A Model Soft Solid Nanocomposite, Vijesh Tanna

*Doctoral Dissertations*

**ABSTRACT**

RHEOLOGICAL PROPERTIES OF A MODEL SOFT SOLID NANOCOMPOSITE

SEPTEMBER 2018

VIJESH A. TANNA

B.S. UNIVERSITY OF ILLINOIS URBANA-CHAMPAIGN

M.S. UNIVERSITY OF MASSACHUSETTS AMHERST

Ph.D. UNIVERSITY OF MASSACHUSETTS AMHERST

Directed by: Prof. H. Henning Winter

The fabrication and physical properties of polymer/clay nanocomposites has received a great deal of interest in both academic and industrial settings. Clay is a natural 2D mineral comprised of stacks of platelets with high aspect ratios held together through electrostatic interactions. Typically, polymer/clay composite are found to have the best physical properties when these clay sheets are randomly dispersed, exfoliated ...