Research, MFL
For any Queries/ Comments/Suggestions
Contact :
Prof Kendra Sharp
ksharp at
mne dot psu dot edu
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1.
Non-spherical electrokinetic particle transport in microfluidic
systems
Electrokinetics
is the motion of fluid or particles under the influence
of an applied electric field. The surface properties of
the channel walls and particles determine if the fluid,
particles, or both are moved by the electric field and
the resulting velocity. Through control of the surface
properties, by material choice or additional surface treatments,
the particle motion can be controlled. The focus of the
work is on the trajectories of cylindrical nanowires as
they move through various channel geometries under the
influence of an applied electric field. With cylindrical
particles, the angle and rotation of the particle is a
critical component of the motion and requires additional
study when compared to spherical particles. Experimental
work has demonstrated that classical theories can be used
to describe the average electrokinetic motion of populations
of nanowires, while ongoing work seeks to determine differences
in motion due to the orientation of the nanowires. The
trajectories of cylindrical particles have been simulated
numerically in a variety of channel geometries. The results
indicate that the motion is strongly dependent on the
initial orientation of the particle as well as the proximity
to one or all walls of the channel. Initial simulations
indicate that channel geometry (such as a corner) may
be useful as a passive feature to induce alignment among
a population of randomly oriented cylindrical particles.
The results of this work are intended to aid in the manipulation
of single particles in devices such as lab-on-a-chip instruments
or incorporated into designs of systems for construction
of nanowire based electronic components.
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2.
Particle separation in microfluidic systems
We
are working to model a new microfluidic particle separation
technique called Deterministic Lateral Displacement (DLD).
The model consists of a microchannel and periodic arrays
of micrometer-scale obstacles. Each column of obstacles
is vertically shifted with respect to the previous column
so fluid coming from the gap between two obstacles encounters
another obstacle in the next column and bifurcates around
the obstacles as it goes along the channel. We are particularly
interested in capitalizing on the flow patterns to separate
particles; conceptually, in the laminar flow regime, particles
smaller than a critical size will remain in their lanes
and follow the streamlines (zigzag mode) while the particles
larger than the critical size will move through the lanes
(displacement mode). This process is applicable to pressure-driven
(PD) flow as well as electrokinetically-driven (EK) flow.
We are currently simulating both PD and EK flow, focusing
on flow characteristics and plan to compare our results
with experimental data obtained in another laboratory.
Personnel:
Shahrzad Yazdi, Scott Davison
3.
Multi-phase transport and fuel cell diffusion media
Personnel:
E.
Caglan Kumbur , Prof.
Matthew. Mench
 
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4.
Velocity characteristics in a propellant manifold
The
main thrust of the investigation is to
quantify velocity charicteristics at the
end of a duct containing a 90 degree bend
and flow development through the bend
at a Reynolds number near 500,000.
To achieve this goal, a new water flow
facility was designed, fabricated, and
constructed to meet the requirements. A
flow rate of 200 gallons per minute can
be pumped through the test section with
1 inch x 1 inch cross-section..
Both static and dynamic pressure measurements
have been taken as part of the initial
effort to characterize the flow. PIV measurements
are planned to describe both the streamwise
and cross stream velocity components.
5.
Development of a piezoelectric
microengine using pulsed catalytic
combustion
The
general premise of the
piezoelectric microengine
is to use pulsed catalytic
combustion to periodically
deform a piezoelectric
crystal and generate an
electrical output. To
date, the pulsed catalytic
combustion used to produce
periodic temperature fluctuations,
which deform the piezoelectric
material, has been demonstrated
through experimental work.
In addition, the experimental
work was simulated using
FLUENT to gain a better
understanding of the flow,
combustion, and heat transfer
processes in the combustor
and to verify the model
can produce reliable and
consistent results. The
experimental and modeling
work is currently being
used to develop a new
planar microengine design.
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