(6hf) Experimental and Numerical Investigations of Particle Flows

Solid particles are commonplace in a wide range of industries and are used in operations, such as mixing, pneumatic conveying, granulation, heat and mass transfer, fluidized beds, tableting, etc. However, in general, the behavior of particles in these systems is still not well understood. The lack of fundamental understanding can lead to poor system performance, uncertainties in system scale-up, delays to process start-up, ineffective operation design and, in some cases, process failure. For instance, particles have a tendency to segregate by size when in motion which can lead to inconsistent product quality (quality control issues) when particles discharge from hoppers. My research interests include improving the understanding of particle-particle and particle-fluid interactions with the goal of more accurate predictive capabilities, resulting in more efficient process design. Additionally, many industrial operations would benefit from particles with specific properties, such as particle size, cohesion level and/or shape, thus I am interested in improving current methods, as well as developing new techniques, to control particle properties.

Research Experience:

Currently, I am a project leader at Particulate Solid Research Inc. (PSRI), a non-profit research consortium of international companies and national labs. As a project leader, I design and manage the execution of research plans to address various particle-technology related problems, e.g., probe development for measuring flow behavior within fluidized beds. Additionally, I am a principal investigator of a research project that focuses on validating drag force models. Momentum is transferred from the fluidizing gas to the particles via the drag force. Thus, valid drag force models are necessary for accurately predicting fluidized bed behavior. Through a thorough analysis of existing drag models, significant gaps in their validation in the parameter space relevant to industrial fluidized beds was identified. Furthermore, large variations between different drag model predictions exist, which make it difficult to know which drag model is appropriate for a system a priori. The main aim of the work is to assess the accuracy of drag models and develop a microscopic understanding of the differences in various drag model predictions.

As a postdoctoral research assistant in the Chemical and Biological Engineering Department at the University of Colorado, I was the lead experimentalist in Prof. Christine Hrenya’s research group. I worked on projects related to particle cohesion and heat transfer. The main objective of these various projects was to develop an improved, fundamental understanding of bulk particle behavior by investigating micro-scale (individual) particle properties and interactions. To achieve these aims, I developed experiments and cost-effective characterization techniques to study the effect of individual particle properties on bulk particle properties. For example, in one project, the effects of cohesion between particles in a fluidized bed were measured and understood via the effects of surface roughness on the cohesion level. Additionally, I mentored and supervised undergraduates to carryout high-fidelity measurements that can be used for model validation. During my postdoc, I gained experience writing proposals, collaborating with industry, and mentoring and supervising undergraduate students in research and in applying for grants to pay for their research stipends.

Prior to my postdoc, I received my PhD from the University of Florida Chemical and Biological Engineering Department where I was advised by Prof. Jennifer Sinclair Curtis. During my PhD, I developed and tested physical models for dense phase gas-solid multiphase flow using computational fluid dynamics. Models were verified by simulating the cratering of a particle bed by a subsonic jet of gas. Experimental results from NASA internship and NASA-FAST lunar gravity flight used to further develop and verify the physical model. Experiments performed at the University of Florida to investigate particle property effects on cratering that provide fundamental understanding of particle shape, benchmark data for computational fluid dynamics simulations and improved crater scaling relationships.

Teaching Interests:

Not only does my background in fluid-particle flows make me a strong candidate for teaching standard fluids based chemical engineering courses, but also allows me to incorporate particle technology into the undergraduate curriculum. Training graduate and undergraduate students in this industrially applicable field will help to prepare a relevant workforce. Additionally, my experience in large-scale, experimental systems provides me with the necessary skills to teach students in unit-operations laboratory and process-control courses.