Computational
Transport Processes
Research
Projects
Turbulent heat or mass
transfer (National Science Foundation CTS-0209758, CBET-0651180;
Direct Numerical Simulations of
turbulent flows with passive heat transfer will provide results needed to test
the present theory and to suggest new approaches. Of particular importance will
be the possibility of relating transport at different Prandtl numbers, Pr, to
turbulence structure. This simulation will provide accurate results for small
Pr (e.g., air with Pr=0.7, and liquid metals with Pr<0.1). In addition,
turbulent reactive flows and the effect of a chemical reaction on the mass
transfer properties will be investigated.
Lagrangian simulation of
scalar transport in wall turbulence (National Science Foundation, CTS-0209758,
CBET-0651180)
In the Lagrangian framework, the
system of reference moves with the fluid particles, or the heat or mass markers
in the case of turbulent transport. In order to apply this methodology, information
along the trajectories of heat or mass markers must be known. A tracking
algorithm is used to monitor the trajectories of these markers in space and
time as they move in a hydrodynamic field created by a Direct Numerical
Simulation. At first, the fluid structures that enhance mixing of heat or mass
markers and move them away from the viscous wall region will be investigated.
The effect of molecular Prandtl or Schmidt number will also be studied. A major
advantage of this approach will be the capability of describing turbulent heat
of mass transfer with a variety of configurations (line source, heated plate,
step change in the temperature of the wall, heated channel) with a very limited
number of numerical experiments.
Heat transport in carbon
nanotube composite materials (Department of Energy, DE-FG02-06ER64239)
Carbon nanotube composite
materials did not live up to expectations regarding enhanced thermal
properties. Even though single-walled and multi-walled carbon nanotubes (CNTs)
have thermal conductivities that are on par with the most thermally conductive
materials known, composites with carbon nanotube inclusions exhibit effective
thermal conductivities that are controlled by the thermal resistance for heat
transfer at the nanotube-matrix material interface. We are exploring the
effects of the interfacial thermal resistance to heat transfer on the effective
conductivity of CNT composites and CNT suspensions. We have developed a
Flow effects on porous scaffolds for tissue
regeneration (National Science Foundation, CBET-0700813; TeraGrid CTS080042)
The objective of this work is to
examine the effects of fluid flow in the form of convective perfusion through
porous scaffolds widely used in tissue engineering applications. The goal is to
characterize the fluid dynamic environment at the interior of three-dimensional
porous scaffolds and its effects on the behavior of seeded bone cells. Such
fundamental understanding, from both experimental and theoretical perspectives,
is critical to the long term success of tissue engineering strategies that use
cell/scaffold constructs as implants. In collaboration with Prof. Sikavitsas, we
investigate the effect of convective flow perfusion in 3D scaffolds having
complex porous architectures on the in vitro generated extracellular matrix,
and we are working to identify the critical flow rate where excessive
detachment of cells occurs. We are
also using lattice Boltzmann methods to characterize in detail the fluid flow
environment within the porous scaffold, while the 3D configuration changes
continuously due to tissue growth, in order to develop a theoretical framework
for the prediction of the applied shear forces in each location. Our Lagrangian
numerical methodology will also be employed to investigate the formation of the
concentration field of nutrients within the scaffold ant to explore the
concentration gradients that are critical for tissue growth.
Simulation of the flow field
that results from two rectangular jets (National Science Foundation, The 3M Company, Nordson Corporation, NSF-DMII-0245324 )
The commercially important process
of fiber melt blowing will be described with an experimentally-verified
model. Melt blowing involves the impact of
high velocity air streams upon a molten polymer to form fine webs of
fiber. In recent years, Prof. Shambaugh's group
developed a model for describing the polymer side behavior. In this model, the air field enters the
equation solutions as a boundary condition.
The model is very good, but sometimes its predictions are only
semi-quantitative. Very recently, our
research group in collaboration with Prof. Shambaugh’s group has used a commercial
computational fluid dynamics software package (FLUENT); this CFD work gives
much more information about the air field than was previously available. We will combine the CFD work (to describe the
air side) with the previously developed model for the polymer side. The goal is to develop an accurate,
comprehensive model for melt blowing.
Development of learning tools
to bridge Economics with Chemical Engineering (National Science Foundation,
DUE-0737182)
This collaborative project with Prof. Kosmopoulou
aims to bring modern techniques that are well-developed in the field of
Economics and Management into the Chemical Engineering classroom, and more
specifically into the Chemical Engineering Design and Engineering Economics
curriculum. The goal is to develop learning material combining economics and
chemical engineering in the form of illustrative examples, classroom
experiments, homework problems, and lecture notes. This material will be
adopted in existing courses during the currently funded Phase 1 of this
project. Selected parts of it will be used for the integration of concepts from
the two disciplines in a new course during Phase 2 of the project, funding for
which will be solicited through the CCLI program in 2010.
Turbulent drag reduction with
macromolecular brushes (Office of Naval Research, N00014-03-1-0684)
The
development of the methodology for friction drag reduction is a subject of
ongoing interest to the Navy. One of the
current research thrusts is the use of polymers/surfactants and microbubbles in
the near-wall region to promote a reduction in the wall shear stress, and hence
in the friction drag. An alternate
solution that does not involve the continuous addition of surfactant/polymers
or microbubbles is proposed in this project. The idea of surface-mounted
polymer chains and nanotubes to modify the near-wall flow field and hence the
wall shear stress is proposed. The aim
is to provide a physical understanding of the mechanics of drag reduction by
this method and to demonstrate the practical viability of the proposed
method.
A
combined experimental and computational approach is taken. Experiments will be carried out in a
fully-developed channel flow facility in which the walls can be easily
replaced. Wall shear stress measurements will be made with walls coated with
different densities of polymer chains/nanotubes (Dr. Newman’s lab). Non-intrusive velocity measurements will be
made using laser Doppler velocimetry (LDV) and Particle Image Velocimetry (PIV)
to document the modifications in the flow structure in the near-wall region (Prof.
Parthasarathy’s group). Direct
numerical simulations (DNS) of the channel flow will be undertaken by our
grooup. In addition, molecular
simulations have been conducted to provide input to the DNS (Prof. Lloyd Lee’s
group).
Transport processes in
microchannels with nanotube brushes (National Science Foundation, Nanonet,
NSF-EPS-0132354)
Carbon nanotubes exhibit
properties that promise to revolutionize technology in the next few decades.
One of these properties is very high thermal conductivity. This project will
investigate the heat transport behavior of surfaces that are covered with
carbon nanotubes. Microchannels with arrangements of nanotubes are particularly
interesting, because of the potential applications for heat dissipation in
microchips. The objective is to explore the feasibility of designing micro-heat
exchangers that will utilize nanotubes as heat conductors.
Scalar transport through
porous media (Petroleum Research Fund, ACS-PRF# 39455-AC9)
Fairly little information of
general applicability is known about scalar transfer in heterogeneous, dense
media. We are studying the transport of a scalar in porous media using flow
simulations at small scales in conjunction with the Lagrangian scalar tracking
method developed by our laboratory for other types of flow (i.e., for
turbulence). The hypothesis is that the medium structure and the fluid
properties are needed to predict the scalar profile in the flow domain.
Different numerical methods, each one appropriate for a particular physical
scale, is utilized for the flow field. Flow in the pore scale will be simulated
with the Lattice Boltzmann Method, initially through unconsolidated media and
later using digital images of actual rocks as the flow domain. Furthermore,
pore network modeling and stochastic methods will be used for the systematic
study of the effects of the medium structure on the transport properties at
larger physical scales.
Multiphase flow through porous
media (Mobil Technology Company, Petroleum Research Fund, ACS-PRF# 35103-G9)
The goal is the macroscopic
modeling of reservoir behavior by using novel computational techniques and by
incorporating more physics into the problem. The result will be a new more
realistic reservoir simulator. State of the art reservoir simulators use
Darcy’s law to predict pressure drop in reservoirs far from the well and a skin
factor close to the well, which models linearly the non-Darcy
pressure drop. A further assumption is that the rock is isotropic. This project
will model the reservoir using anisotropic permeability for Darcy’s law and a
more realistic relationship (like Forchheimer’s equation) for the non-Darcy
regime.
Lattice Boltzmann method for
multiphase flow through porous media (Mobil Technology Company, Petroleum
Research Fund, ACS-PRF# 39455-AC9)
A Lattice Boltzmann Method will be
developed to describe flow through porous material in the microscopic level.
Modern visualization techniques, like Magnetic Resonance Imaging or Nuclear Magnetic
Resonance, can give a detailed view of the pore network in a microscopic scale.
This can serve as the boundary for the application of LBM.
Model Based Simulator for high
velocity flow through porous media (National Science Foundation, NSF-CMS-0084554)
In this project, we plan to
develop an integrated simulator for flow through heterogeneous porous materials
using a hierarchy of simulations. Current approaches involve the use of
simulations having a single physical scale (see the above two projects).
However, recent advances in High Performance Computing have made it possible to
increase significantly the problem size. The challenge is to combine the
individual simulations into an integrated multiscale system that will be able
to include all physical scales and will self-adjust in accordance with the
input data. Emphasis will be placed on the portability, scalability, efficiency
and extensibility of the final product. The simulator will be an improved
prediction tool for hydrocarbon reservoir management and will be ready for use
on integrated grid architectures, as they become available.
High Performance Computation
Grid Applications in Chemical Engineering
This project will combine emerging
research needs in Grid computing with new research directions in engineering
applications. Specifically, this study
will design, implement and deploy a Problem Solving Environment (PSE) for
engineering management of complex physical systems. This Engineering Management
System (EMS) will enable multiscale simulation of multiphase flow through
porous media, with asynchronous, bidirectional feedback between software
components, and will be applicable to a wide variety of applications by
allowing plug-and-play capabilities. The specific testbed application for the
PSE is the management of a hydrocarbon reservoir. Recent advances in Science
Portal technology, can provide the underlying structure that such PSEs require.
A cohesive, multi-university (The University of Oklahoma, University of
Illinois at Urbana-Champaign, Clarkson University) research group that is
focused on the use of high performance computers in chemical engineering
practice has been formed to promote these ideas and to explore the possibility
of funding this project.
DVP's
home
| UPDATED:
October 13, 2008