UF Chemical Engineering > People > Faculty > Jennifer Sinclair
Curtis 

Jennifer Sinclair Curtis
Ph.D., 1989, Princeton University

Distinguished Professor


Faculty
Web Page 
Areas 
Fluidization 
Particle Technology 
CFD and DEM modeling for particulate flows 



Particulate flows are prevalent across a diverse range of
industrial and geophysical processes. Examples include pharmaceutical
processes, conveying lines for transporting minerals, ores,
food and agricultural products, fluidized bed reactors, debris
flows, and sediment transport. Several ongoing projects are
outlined below: 
Particle Segregation in Hopper Flows 
Granular materials typically consist of particles
with a distribution of sizes, shapes, and densities,
which, upon handling, may induce segregation of the
material. This segregation of granular materials is
undesirable for many solids handling processes as
the product quality is often contingent on maintaining
blend homogeneity – such as tablet production
in the pharmaceutical industry. Our research uses
the discrete element method (DEM) to investigate the
effects of various hopper geometries and particle
properties on the segregation of a spherical, bidisperse
granular material during hopper discharge. Current
studies also incorporate the effect of particle cohesivity
due to liquid bridging. The computational results
are compared to those from a small experimental system
which is the ASTM standard test for sifting segregation. 



NonIntrusive Measurements of Dilute and
DensePhase FluidSolids Flows using Laser Doppler Velocimetry
(LDV) 

Currently,
fundamental predictive models for fluidparticle flows
are for processes operating exclusively in either
the inertiadominated regime  where the influence
of the fluid phase on direct interactions between
particles is neglected, or the macroviscous regime
 where the fluid phase plays the significant role
in the mechanics of particle momentum transport. Both
of these regimes of flow occur in gassolid and liquidsolid
systems. One key limitation impeding the development
of fundamental models in the ‘transitional’
regime  between the inertiadominated and the macroviscous
regimes  is the lack of detailed, nonintrusive flow
measurements. Hence, this research involves LDV experimentation
in a unique, pilotscale, slurry flow loop. By varying
the flow velocity, particle concentration, and particle
size, we span the range of particulate flow regimes.
In addition, through the use of index of refraction
matching, both dilute and densephase particle flows
can be explored. 


Development of a Constitutive Model for
Stress/Viscosity of NonSpherical Particles 
Virtually all solid handling operations involve nonspherical
particles, and the influence of particle shape on
particle flow behavior is significant. However, most
fundamental studies of particulate material undertaken
to date involve spherical particles. Hence, the present
work aims at developing constitutive relations for
the particlephase stress, needed in continuumbased
models, incorporating the effect of particle shape.
In order to develop such relations, we investigate
the flow of particles of different shapes  various
polygons and elongated particles with various aspect
ratios  via DEM in planar shear flow. The particlephase
stress associated with these various shaped particles
is then “measured“ as a function of the
solids volume fraction, coefficient of restitution,
and solids friction. 



CFD Simulation of Rocket Exhaust Interaction
with Lunar Soil 

Debris
transport due to rocket plume impingement onto lunar
soil can cause significant damage to spacecraft and
other surrounding equipment during lunar landing operations.
Hence, the liberation of dusty lunar soil is potentially
the highest risk facing lunar exploration system architectures.
In order to mitigate this problem, we are developing
a continuumbased, twophase flow simulation model,
in collaboration with CFD Research Corporation, to
predict the severity and range of dust and debris
transport and to design debris impact mitigation strategies.
Specifically, one current area of focus is the improvement
of lunar soil models which is key to accurate prediction
of cratering and particle liberation. 


Recent Publications 
1. 
Y. Guo and J. Curtis, “Discrete Element Method Simulations for Complex Granular Flows” (Invited), Annual Review of Fluid Mechanics, in press (2015) 
2. 
S.B. Kuang, C.Q. LaMarche, J. Curtis, and A. B. Yu, “Discrete Particle Simulation of JetInduced Cratering of a Granular Bed”, Powder Technology, 239, 319336 (2013) 
3. 
D. Rangarajan, A. Mychkovsky, S. Benyahia, and J. Curtis, “Continuum Model Validation of Gas Jet Plume Injection into a GasSolid Bubbling Fluidized Bed”, AIChE Journal, 59, 32473264 (2013) 
4. 
P. Bunchatheeravate, Yusuke Fujii, Shuji Matsusaka, and J. Curtis, “Prediction of Particle Charging in a Dilute Pneumatic Conveying System”, AIChE Journal, 59, 23082316 (2013) 
5. 
Y. Guo, C. Wassgren, W. Ketterhagen, B. Hancock, B. James and J. Curtis, “A Numerical Study of Granular Shear Flows of Rodlike Particles Using the Discrete Element Method”, Journal of Fluid Mechanics, 713, 126 (2012) 



