Department of Chemical and Biological Engineering - Archive

Associate Professor

3037 Sweeney Hall
Iowa State University
Ames, IA 50011-2230

Phone (515) 294-6438
Fax (515) 294-2689
vigiliastate.edu

Education
PhD, ChE, University of Michigan, 1990
MS, ChE, University of Michigan, 1986
BS, ChE, University of New Mexico, 1985

Teaching/Office Hours Schedule

Research Interests
I am interested developing and validating new models and computational methods for simulating the behavior of multiphase processes, particularly as they relate to important technological problems such as nanoparticle and advanced materials synthesis, enhanced oil recovery and aquifer remediation, and development of novel reaction engineering and separation approaches for algaculture.

Research Projects

Kinetics of Aggregation and Breakage
Examples of coagulation, clustering, aggregation, breakage, and fragmentation are ubiquitous in nature and play an important role in processes as diverse as nanoparticle synthesis, blood coagulation, polymerization, crystallization, aerosol dynamics, and even galactic clustering. We are particularly interested in extending aggregation theory by developing new analytical solutions and numerical methods to solve population balance equations. We are also developing methods for obtaining aggregation and breakage rate kernels used in macroscopic descriptions of aggregation from molecular simulations such as molecular and Brownian dynamics.

Reactive Precipitation
The production of nanoparticles with well-controlled properties is an important and difficult materials synthesis problem. Such processes often employ reactive precipitation in a batch, semi-batch, or a continuous-flow microreactor, and the interaction between mixing, nucleation, growth, and agglomeration is complex. We are using computational fluid dynamics coupled with mathematically tractable population balance equations to develop accurate models for predicting particle properties.

Vibration-induced Mobilization of Oil Trapped in Porous Media
The development of methods for mobilizing residual organic liquids trapped in porous media is becoming increasingly important as world demand for oil increases and because of the need to remediate aquifers degraded by slow-dissolving organic contaminants. Low-frequency elastic wave stimulation is one such technique, but until recently the lack of a mechanistic understanding of the effects of vibration on mobilization of oil ganglia has prevented the method from being applied predictably in the field. In conjunction with our geophysicist collaborator, Prof. Igor Beresnev, we have developed a capillary-physics explanation to explain vibration-induced mobilization of trapped non-wetting organic fluids in porous media and have carried out bench-scale experiments to validate this mechanism. However, many issues remain unresolved before vibration-based mobilization techniques can be optimized and implemented reliably in the field, including delineating the effects of pore geometry, as well as the roles of viscous forces, surface wetting, and droplet breakup. We are currently working to extend our theory to account for these other factors through the use of mathematical analysis, computational fluid dynamics simulations, and flow visualization experiments.

Novel Photobioreactors
Microalgae-based production of transportation fuel has become a high priority on the national research agenda because of the potential that this technology possesses for replacing non-renewable fuels and reducing greenhouse gas emissions. While much attention has been focused on developing elite strains of microorganisms for this purpose, perhaps the largest barrier to large-scale implementation of algae-based biorefineries are the process engineering challenges related to efficiently delivering light and nutrients to these microorganisms and harvesting desired products. We are working on novel photobioreactors that have the potential for simultaneously increasing biofuel production rates and separating biofuel products while minimizing energy utilization.

Multiphase Couette-Taylor Flow
The vortex structure in a Couette-Taylor (CT) cell has applications to a variety of chemical processing problems, such as emulsion polymerization and extraction. For example, CT flow can be used to closely approximate a plug-flow reactor for sufficiently large rotation rates and annular gap widths. The optimization of these systems requires a fundamental understanding of the effect of various operational parameters on the hydrodynamic structure and mixing characteristics. Although there has been much progress in the understanding of homogeneous CT flow, relatively little is known about the behavior of multiphase CT flow. We are working to overcome this gap for liquid-liquid systems through the use of particle image velocimetry experiments and CFD calculations.
 
Selected Publications
G. Pranami, R. D. Vigil, and M. H. Lamm, Molecular dynamics simulations of fractal aggregate diffusion. Physical Review E, 82, 051402 (2010).

J. C. Cheng, R. D. Vigil, and R. O. Fox, A Competitive Aggregation Model for Flash
NanoPrecipitation. Journal of Colloid and Interface Science, 351, 330-342 (2010).

Beresnev, I., W. Li, and R. D. Vigil, "Condition for Breakup of Non-Wetting Fluids in Sinusoidally Constricted Capillary Channels," Transport in Porous Media (in press) 2009.

Vigil, R. D., "On Equilibrium Solutions of Aggregation-Fragmentation Problems," Journal of Colloid and Interface Science, 336, 642 (2009).

Mokhtari, T., A. Chakrabarti, C. M. Sorensen, C. Cheng and D. Vigil, "The Effect of Shear on Colloidal Aggregation and Gelation Studied Using Small-Angle Light Scattering," Journal of Colloid and Interface Science, 327, 216 (2008).

Markutsya, S., S. Subramaniam, R. D. Vigil, and R. O. Fox, "On Brownian Dynamics Simulation of Nanpoarticle Aggregation," Industrial & Engineering Chemistry Research, 47, 3338 (2008).

Vigil, R. D., I. Vermeersch, and R. O. Fox, “Destructive Aggregation: Aggregation with Collision-Induced Breakage,” Journal of Colloid and Interface Science, 302, 149-158 (2006).

Li, W., R. D. Vigil, I. A. Beresnev, P. Iassonov, and R. Ewing, â€œVibration-Induced Mobilization of Trapped Oil Ganglia in Porous Media: Experimental Validation of a Capillary Physics Mechanism,” Journal of Colloid and Interface Science, 289, 193 (2005).

Wang, L., R. D. Vigil, and R. O. Fox, â€œCFD Simulation of Shear-Induced Aggregation and Breakage in Turbulent Taylor-Couette Flow,” Journal of Colloid and Interface Science, 285, 167 (2005).

Wang, L., D. L. Marchisio, R. D. Vigil, and R. O. Fox, â€œCFD Simulation of Aggregation and Breakage Processes in Laminar Taylor-Couette Flow,” Journal of Colloid and Interface Science, 282, 380 (2005).

Marchisio, D. L., J. T. Pikturna, R. O. Fox, R. D. Vigil, and A. A. Barresi, “Quadrature Method of Moments for Population Balance Equations,” American Institute of Chemical Engineers Journal, 49, 1266 (2003).

Marchisio, D. L., R. D. Vigil, and R. O. Fox, "Quadrature Method of Moments for Aggregation-Breakage Processes," Journal of Colloid and Interface Science, 258, 322 (2003).