The Hrenya Research Group investigates a variety of complex fluids, such as gas-solid systems, granular materials, and aerosols. Our work is fundamental in nature and is applied to a wide range of applications: improving the efficiency gasifiers used for energy production, developing novel heat transfer methods for concentrating solar power plants, mitigating the ejection of lunar soil upon spacecraft landing, and predicting the agglomeration of cohesive particles found in nature or industry. We use a combination of theory, computation, and experiments to probe these systems.

2017 Hrenya Research Group
(L-R): Casey, Ignacio (visiting faculty from the University of Madrid), Aaron, Peiyuan, Ipsita, Christine, Steven, Kevin, William, Haley, Lucas

Recent Group News...
Prof. Christine Hrenya
Prof. Christine M. Hrenya is the recipient of the AIChE 2020 Shell Thomas Baron Award in Fluid-Particle Systems, an award that recognizes a researcher who has made a significant impact in the fluid particle systems field or related subjects.

Prof. Christine Hrenya
Prof. Christine M. Hrenya delivered the Jacobus van 't Hoff lecture for the TU Delft Process Technology Institute on September 17, 2020.  The presentation was titled "Learning from the unexpected: Surprising behaviors in particulate systems." Learn more here.
A variant of this lecture was also presented as part of the Granular Matter webinar series in October 2020, and is available for viewing on-line here.
Prof. Christine Hrenya receives $750,000 grant sponsored by the U.S. Exascaling Computing Project. Read more here.
Dr. William Fullmer is the recipient of the 2018 American Institute of Chemists Postdoc Award, presented by the Department of Chemical Engineering in recognition of his excellence in research, academics, and service while at CU. His 2017 paper in the Annual Review of Fluid Mechanics was also recognized by the Web of Science as a “highly cited paper” – i.e., citation count in top 1% of Physics papers published in 2017. William has recently started a position at the Department of Energy National Energy Technology Laboratory. Congratulations, William, on these well-deserved recognitions!


Dr. Abhi Shetty of Anton Paar recently visited the Hrenya Research Group to install and train students on a new, state-of-the-art powder rheometer.  This generous donation will allow group members to characterize more cohesive particles than currently possible, and poises the lab for a significant leap in its research on cohesive-particle flows.
Congratulations to Ipsita Mishra who was recently awarded the Beverly Sears Graduate Student Grant.
Keep up the great work Ipsita!
Professor Christine Hrenya was recently awarded $3M in US DOE funding for Phase-II of the ongoing MFiX-DEM enhancement project. This project is a collaboration with Professor Thomas Hauser of CU's Research Computing, Dr. Ray Grout of the National Energy Technology Laboratory and Dr. Ray Cocco of Particulate Solid Research, Inc. Congratulations Christine and the rest of the MFiX-DEM team!


In early Dec. 2016 Drs. Peiyuan Liu and William Fullmer got to tour CU Research Computing's new supercomputer Summit, scheduled to replace Janus in early 2017.


Congratulations to Professor Christine Hrenya for chairing a successful AIChE Annual Meeting in San Francisco. In between hosting special and award sessions, Christine presented at a special session celebrating Prof. Sundaresan (above) and gave a plenary lecture. Dr. Peiyuan Liu, Dr. Casey LaMarche, Dr. William Fullmer, Aaron Lattanzi and Kevin Kellogg also attended and presented recent research results.


Congratulations to recent Hrenya Group Alumnus Dr. Professor Aaron Morris who will be joining the faculty in Mechanical Engineering at Purdue University beginning Jan 2017. Purdue's ME department is currently ranked in the top ten - both undergrad and grad programs - by the US News & World Reports. Congrats Aaron!


The Hrenya Group branched out to several conferences and seminars this summer. Prof. Christine Hrenya presented a plenary lecture on clustering at the triennial International Conference on Multiphase Flow in Firenze (Italy), presented on cohesive granular matter at the Granular Matter Gordon Research Conference at Stonehill College (outside of Boston), and attended the EPIC (Enabling Process Innovation through Computation) workshop at the Banff International Research Station. Dr. Peiyuan Liu traveled to Morgantown, WV to attend NETL's Workshop on Multiphase Flow Science and present on recent progress of the MFiX enhancement project. Aaron Lattanzi gave a short talk and presented an associated poster on a CFD-DEM heat transfer boundary condition at the 24e Congrès international de mécanique théorique et appliquée à Montréal.     


Congratulations to recent Hrenya Group Alumnus Dr. Peter Mitrano on his new Instructor position at Colorado Mesa University in the Dept. of Mechanical Engineering. Congrats Pete!


Professor Christine Hrenya was recently featured in an ASCR Discovery article highlighting her contributions to the SunShot Initiative. Nice work Christine & Hrenya Group members Dr. Aaron Morris, Aaron Lattanzi and Ben Grote.


The group after a long, hard day of trail breaking in the Indian Peaks Wilderness for the 2016 summer Hrenya Group Volunteer Day. Hopefully we will return next summer to enjoy our hard work with a jaunt from Brainard Lake on a completed trail.


Hrenya Group 2016 Graduates: Dr. Kyle Berger & Ben Grote


 Congratulations to Ben Grote for winning the 2016 Donald Mackinson Student Writing Award on research performed in the Hrenya Group. Ben plans to use the award money to finance some backpacking trips this summer. Great job, Ben! 
Congratulations to Dr. Kyle Berger for successfully defending his PhD thesis on lunar regolith erosion. We wish him luck at his new position at Practical Scientific Solutions in North Carolina.

Professor Christine Hrenya has been appointed as an Associate Editor for the AIChE Journal, one of the most important academic journals in the broad field of Chemical Engineering. Congratulations to our advisor on such a tremendous accomplishment!


The Hrenya Group had 7 presentations at the 2015 Annual AIChE Meeting in Salt Lake City, Utah. Prof. Christine Hrenya and Drs. Casey LaMarche, Peiyuan Liu, William Fullmer and Aaron Morris all presented on current research. Pictures above show (clockwise from left): Casey with Prof. John Grace after presenting at his honorary session; Peiyuan presenting on sensitivities of CFD-DEM simulations; the Utah State Capitol building; front; and side views of the LDS Church's Salt Lake Temple.


For the 2015 fall semester Hrenya Group Volunteer Day, the group assisted the Boulder Open Space and Mountain Parks (OSMP) dept. in constructing a new bee garden. The pollinator-friendly flowers planted in the bed will help sustain native pollinators throughout the entire season, after agricultural nectar sources have dwindled. Stop by the South Teller Trailhead to check it out. 


Ph.D. Candidate Kyle Berger spent Summer 2015 at Jet Propulsion Laboratory in Pasadena, CA as part of his NASA fellowship. He worked with Dr. Rudranaryan Mukherjee on integrating collision detection between generic triangle meshes into an in-house code.


Hrenya Group alumni and continued collaborator Prof. Jia Chew was the recipient of the 2015 Singapore Youth Award (SYA). The SYA is Singapore's highest accolade which honors outstanding young people who both demonstrate excellence in their respective field and contribute to society through community involvement. Jia's interview can be viewed here and her SYA bio is available here. Congratulations, Jia, on such a prestigious honor.
Prof. Christine Hrenya and Dr. William Fullmer paid a visit to collaborator Prof. Vicente Garzó at his home institute, the Universidad de Extremadura in Badajoz, Spain. Significant progress was made on a new kinetic theory and its associated linear stability analysis during the two week visit. At left, the SPhinX Group treat Christine and William to lunch in Portugal.
A new tradition was started in 2015: the Hrenya Group Volunteer Day.  This past April on Arbor Day, the group worked with the great staff at Boulder County Parks and Open Space to plant trees at Boulder County Fairgrounds.  It was a rewarding experience to give back to the community for all of the trails and open space we enjoy year round.
Professor Hrenya was selected to Chair the 2016 AIChE Annual Meeting.  This premier annual gathering of >5000 chemical engineers will take place in San Francisco in November.
Dr. William Fullmer was invited to present at the 2015 Japan-US Seminar on Two-Phase Flow Dynamics. The conference is sponsored by the NSF and was hosted at Purdue University (William's alma mater). His presentation focused on continuing gas-solid instability research in collaboration with Peter Mitrano (group alumni), Xiaoqi Li and Xiaolong Yin (Colorado School of Mines), and Guodong Liu (Harbin Institute of Technology).
Dr. Aaron Morris was recently awarded a 2015-2016 grant of 5,000,000 core hours on Titan, one of the world's fastest supercomputers.  This DOE-sponsored award will be used to simulate a novel, muliphase heat transfer system for use in concentrating solar power plants.  This work, being carried out with collaborators at ORNL and NREL, is part of U.S. SunShot Initiative.
Prof. Christine Hrenya was presented witht the the 2014 AIChE Particle Technology Forum (PTF) Lectureship Award in Fluidization and the 2014 PTF Service Award at the Annual AIChE Meeting in Atlanta.
Dr. Casey LaMarche was invited to give an oral presentation of her work at the 2014 Gordon Research Conference of Granular and Granular-Fluid Flow (Easton, Ma).  Her talk, entitled "Critical Role of Surface Roughness in Predicting Fluidization of Cohesive Particles," was part of a short series of slots designed to highlight the innovative work of junior scientists.
Ben Grote, an undergraduate researcher working with Dr. Aaron Morris, received an award for the poster he presented at the 2014 Rocky Mountain Advanced Computing Consortium (RMACC) High Performance Computing Conference.  Ben’s research, supported by the U.S. SunShot Initiative,  focuses on modeling a novel heat exchanger that uses solid grains as the heat transfer fluid.  Congratulations, Ben!
Ph.D. candidate Peter Mitrano was named the 2014 recipient of the Max S. Peters Outstanding Graduate Award by the Department of Chemical and Biological Engineering.  Congratulations to Peter on this recognition of his outstanding dissertation research!
A recent publication by Ph.D. candidate Peter Mitrano (Journal of Fluid Mechanics, 738, R2, 2014) was selected as the focus article in a JFM Focus on Fluids piece, authored by Professor Michel Louge of Cornell University.  Peter's work shows that kinetic-theory predictions of clustering instabilties perform well despite a violation of their low-Knudsen-number assumption (see figure), a surprising results which bodes well for the widespread applicability of such models.  This work was also featured by ACS.
Prof. Jia Chew, who recently began a tenure-track position as Nanyang Technological University (Singapore), was named the 2013 recipient of the AIChE George Klinzing Best Ph.D. in Particle Technology Award.  Congratulations, Jia, on a well-deserved honor!
Prof. Hrenya was appointed as an Editor of Aerosol Science & Technology and received the 2013 Boulder Faculty Assembly Teaching Excellence Award, which is bestowed to four faculty at the University each year.  She is also leading two new research awards:  a $1.5M industry-sponsored grant for multiphase flows involving cohesive particles and a $450K grant under DOE's SunShot Initiative.
Recent graduate Carly Donahue had her Ph.D. research on agglomeration among wetted solids highlighted in the journal Nature.  As part of this work, Carly put a unique spin on a common desktop toy, the Newton’s cradle, by immersing it in liquid before pulling on the pendulum.  The results were not what was expected based on our experience with the toy, but a careful theoretical analysis helped to tease out the important physics.  Carly is now performing post-doctoral research at CalTech.



College of Engineering and Applied Science
Department of Chemical and Biological Engineering
Christine M. Hrenya: hrenya@colorado.edu