Title: Recent progress of radiation modeling in combustion environment
Abstract: Thermal radiation is an important heat transfer mechanism in combustion environment, such as in fire and gas turbine combustors. Emitted and absorbed by participating media such as CO2, H2O, CO and soot, thermal radiation can change temperature distribution, and subsequently impacts ignition and extinction of flames as well as pollutant emission. Thermal radiation that reaches the combustor enclosures contributes directly to local heat flux and can sometimes lead to increased thermal stress and eventual failure of the enclosing material. Modeling of radiation in combustion systems has always been a challenge, due to its complexity and potentially prohibitive computational cost. In this presentation, we present our recent efforts in applying Monte Carlo ray tracing solver with line-by-line spectral dataset to a series of flames, including laminar flames, a small heptane pool fire, and a gas-turbine combustor. Characteristics of radiation in combustion is delineated through these examples and a reduced-order model is proposed. Finally, our latest effort in developing a GPU-accelerated Monte Carlo ray tracing (MCRT) solver is presented. The computational cost is significantly reduced, making the solver a possible game-changer for modeling thermal radiation in combustion applications.
Bio: Prof. Xinyu Zhao is an associate professor at University of Connecticut. She joined the Mechanical Engineering Department in Spring 2015 as an assistant professor, and prior to that, she was a postdoctoral research fellow in Combustion Energy Frontier Research Center at Princeton (2014), co-sponsored by Sandia National Laboratory and Pennsylvania State University. She received her Ph. D. degree in Mechanical Engineering from Pennsylvania State University (2013), and she received her Bachelor’s and Master’s degrees in Thermal Engineering from Tsinghua University in 2006 and 2008, respectively. Prof. Zhao’s research program is supported by NSF CISE, the American Chemical Society Petroleum Research Fund, NASA, NSF C-BET, AFOSR, and ONR. She has also been actively working with industrial partners such as FM Global and Raytheon Technologies Research Center. Prof. Zhao is the recipient of the AFOSR YIP award, NSF CAREER award, and Combustion institute’s Irvin Glassman Young Investigator award. Her research interest includes detailed radiation modeling for multiphase combustion systems, turbulent combustion modelling, the interplay between experiments and computation, as well as high-performance computing.
Title: Computational-Analytical Integral Transform And CPU-Intensive Simulations In Heat And Fluid Flow
Abstract: Computational fluid dynamics and heat transfer has been advanced since the second half of the 20th century, in parallel to computer hardware evolution, offering simulation tools for modern thermal and fluids engineering design. Nevertheless, classical analytical approaches for partial differential equations remained in use, along this same period, due to benchmarking and preliminary conceptual design needs. Analytical methods offer evident advantages in precision, robustness, and computational speed, but are very restricted by the complexity of the mathematical formulations. To narrow this gap, hybrid numerical-analytical methodologies have been proposed along the way to benefit from both the accuracy and robustness of an analytic-based solution path and the flexibility of numerical methods. One such hybrid approach is the so called Generalized Integral Transform Technique (GITT), which is a generalization of the classical integral transform method. The immediate gain was the expansion of the benchmarks database for the verification of numerical codes and the expansion on the classes of problems that can be dealt with in preliminary design. However, the GITT was progressively extended for about forty years, leading to a widely applicable computational-analytical approach that deals with nonlinear formulations, irregular domains, heterogeneous media, coupled problems, moving boundaries, boundary layer and Navier-Stokes equations. Also, in CPU-intensive simulations that require numerous evaluations of a partial differential system solution, which may include optimization, inverse problem analysis, simulation under uncertainty, and physically informed neural networks, the analytic nature behind the hybrid methodology leads to more evident advantages. The GITT is here reviewed and illustrated, emphasizing recent methodological developments, for two selected transport phenomena forward-inverse problem solutions.
Bio: Prof. Renato M. Cotta was born in Niterói, Brazil, on March 5th, 1960. He obtained his B.Sc. in Mechanical-Nuclear Engineering, at the Federal University of Rio de Janeiro, UFRJ, Brazil, in 1981, and his PhD in Mechanical-Aerospace Eng. from North Carolina State Univ., NCSU, USA, in 1985. He became Assistant Professor at the Aeronautics Technological Institute, ITA, Brazil, 1985-1987, then Associate Prof., at UFRJ, in 1987, and Professor, at COPPE-UFRJ in 1994, and at POLI-UFRJ in 1997, until the present. Author of around 600 articles, 10 books, and supervisor of 49 MSc, 39 PhD, and 18 PosDocs. He is member of 15 Editorial Boards, including Int. J. Heat & Mass Transfer, Int. Comm. Heat & Mass Transfer, Int. J. Thermal Sciences, and Editor of the Annals Braz. Academy of Sciences. Served as President of the Braz. Association of Mechanical Sciences & Engineering, ABCM, from 2000-2001, as member of the Scientific Council, International Centre for Heat & Mass Transfer, ICHMT, since 1993, of the Executive Comm. ICHMT, 2006-2022, ICHMT EC Chairman, 2017-2018, and Congress Comm., Int. Union of Theoretical & Applied Mechanics, IUTAM, 2012-2018. Served as Exec. Director for the Brazilian Academy of Sciences, 2012-2015. He received the ICHMT Hartnett-Irvine Award, 2009 and 2015, the ICHMT Fellowship Award, 2019, the National Order of Scientific Merit, Brazil, in 2009 (Comendador) and 2018 (Grã-Cruz), and the National Order of Naval Merit, Brazil, 2018. He was awarded the prestigious Luikov Medal of the ICHMT, 2022. Member of the Brazilian Academy of Sciences, since 2009, National Engineering Academy, since 2011, and The World Academy of Sciences, TWAS, since 2012. Holds the Doctor Honoris Causa title from Université de Reims, URCA, France, 2018. President of the National Commission of Nuclear Energy, CNEN, both regulatory body and science promoter in nuclear energy in Brazil, 2015-2017. Adjunct Professor at the University of Miami, 1993-2005, and Leverhulme Trust Visiting Prof. at Univ. College London, UCL, UK. Member of the National Council of Energy Policy, CNPE, Ministry of Mines and Energy, Brazil, 2020-2022. Member of Technical Working Group (TWG) in Nuclear Desalination, IAEA, 2021-2024. Since 2017, Senior Technical Consultant (Amazul Defense Tecnologies), in Nuclear and Technological Development, for the Brazilian Navy.
Title: Data-driven reduced-order modeling for large-scale fluid models
Abstract: Computational fluid mechanics produces high-dimensional discretizations of thermal fluid systems. The use of these computationally expensive simulations in uncertainty quantification, control, design and long-time evolution is often prohibitive. In this talk, we first present data-driven reduced-order modeling as a class of methods to approximate high-dimensional dynamical systems with low-dimensional systems, often characterized by the dynamically relevant solution spaces. In particular, we will discuss the operator inference framework and illustrate how one can learn reduced-order models non-intrusively from high-dimensional data, and how additional knowledge—which is often present about fluid dynamical and other mechanical systems—can be embedded as constraints for the resulting optimization problem. We also present several extensions that focus on preserving interesting structures in the dynamics, such as symmetries, conservation principles, symplecticity. We will illustrate the results on a 2d rocket combustion application as well as some energy-preserving systems where we leverage the Hamiltonian structure in the model learning framework. This guarantees that the learned models are long-term stable and energy-conserving. Several fluid flows are shown as example applications
Bio: Boris Kramer is an Assistant Professor in Mechanical and Aerospace Engineering at the University of California San Diego. Prior to joining UC San Diego, he spent four years as a Postdoctoral Associate in the department of Aeronautics and Astronautics and the Aerospace Computational Design Lab (ACDL) at the Massachusetts Institute of Technology (MIT). He received his M.Sc. (2011) and Ph.D. (2015) in Mathematics from Virginia Tech. Prior to that, he studied Mathematics in Technology and Mechanical Engineering at the University of Karlsruhe (now KIT), Germany. He is a member of the Society for Industrial and Applied Mathematics (SIAM), and a Senior Member of AIAA where he also serves on the Multidisciplinary Design Optimization and Nondeterministic Approaches Technical Committees. He is a 2022 NSF CAREER Awardee and won a DoD Newton Award in 2020. His research is funded by the Office of Naval Research (ONR), the Defense Advanced Research Projects Agency (DARPA) and the National Science Foundation. His research interests are to develop computational methods and numerical analysis for control, optimization, design and uncertainty quantification of complex and large-scale systems.
Title: Mission Impossible: 3D imaging, quantification and visualization of microbial biofilms in fluid-filled opaque porous media
Abstract: Exploring biofilms in three dimensions in porous media is a long-standing challenge. X-ray tomography allows for visualization of a variety of porous materials and associated processes, but because of the absence of a significant photon cross-section for biofilms (it rather closely resembles the aqueous phase in porous media), getting at the three-dimensional architecture of biofilms in porous media is challenging. However, by innovative use of contrast agents, it is possible to separate the biofilm from porous medium and aqueous phase, and to make a variety of quantitative measurements in support of the overall objective of better understanding of biofilm growth and function. This allows for applications in a variety of fields such as groundwater remediation, microbial fuel cells, enhanced oil recovery, clogging of trickling filters, and fouling of medical implants.
In this work, we use micro-imaging to study the effects of flow rate on three-dimensional growth of biofilm in porous media. The images allow us to gain a better understanding of how biofilms grow and interact with the pore geometry, nutrients, and the fluid flow environment in the subsurface. In this particular study, three flow rates were applied to evolving biofilms, and observed after a growth period of 11 days. At the end of the growth period, all columns were scanned using x-ray computed microtomography and a barium sulfate-based contrast agent to distinguish the biofilm. Reduction in permeability due to biofilm growth was studied using both transducer-based pressure drop measurements and image-based calculations.
A combination of results from these different measurements suggest that biofilm growth was oxygen limited at the lowest flow rate, and affected by shear stresses at the highest flow rate. We hypothesize that the interplay between these two factors drives the spatial distribution and quantity of biofilm growth in the class of porous media studied here. Our approach opens the way to more systematic studies of the structure-function relationships involved in biofilm growth in porous media.
Bio: Dr. Wildenschild is a Professor of Environmental Engineering in the School of Chemical, Biological, and Environmental Engineering at Oregon State University, and the Jon and Stephanie DeVaan Chair and Executive Director for Clean Water Initiatives at OSU.
Her research focuses on flow and transport in porous media, with the goal of answering questions of relevance to subsurface water pollution and energy-related storage challenges. Recent work includes optimization of geologic storage of anthropogenic carbon dioxide; colloid-facilitated transport of contaminants in groundwater; exploration of biofilms in porous media using high-resolution 3D imaging, and fundamental investigations in support of more effective groundwater remediation techniques. She is the recipient of the 2023 Interpore Society’s Honorary Lifetime Award, and was the 2014 Henry Darcy Distinguished Lecturer in Groundwater Science
Title: New generation functional surfaces for manipulation of phase change phenomena
Abstract: Boiling, cavitation, droplet condensation and freezing are basic phase change phenomena. Performance enhancements and energy efficiency can be achieved with surface modification for these phase change phenomena. As a result, many surface modification techniques have been proposed and investigated in the literature. One of the most promising approaches include the use of modified surfaces with mixed wettability along the surface, which are capable of manipulating the phase change phenomena and pay way to energy and biomedical applications. The optimization efforts for various modified surfaces in boiling, cavitation, dropwise condensation and freezing could be made so that with the optimum configurations of surfaces with mixed wettability depending on the application and phase change phenomenon it will then be possible to have significant energy saving and efficiency in thermal-fluids systems involving phase change. In this talk, research efforts and recent developments in this field will be discussed.
The second part of the talk will focus on an effective and practical method for having the same effect of modified surfaces with surface enhancements via next generation bio-coatings based on hyperthermophilic archaea and antifreeze proteins, which are durable, environmentally friendly, inexpensive, have unique structures and offer surface modification without the use of any cleanroom fabrication techniques. The results of fundamental studies on these surfaces will be presented for boiling, dropwise condensation and freezing.
Bio: Ali Koşar is a Distinguished Research Professor at Sabanci University. He earned his master's and doctoral degrees in Mechanical Engineering from Rensselaer Polytechnic Institute. He is focusing on the design and development of new generation micro heat sinks with functional surfaces and microfluidic devices including cavitation on chip devices. His research interests constitute a spectrum covering heat and fluid flow in micro/nano scale, condensation, boiling heat transfer, microfluidic systems, freezing and cavitation. He co-authored over 170 research articles in top journals and 80 conference papers in prestigious international conferences. He has also a co-inventor on 8 granted patents and 10 pending patent applications. He received numerous national and international honors, including the µFIP Prominent Researcher Award" in the 2021 micro Flow and Interfacial Phenomena (µFIP) Conference, METU (Middle East Technical University) Prof. Mustafa N. Parlar Foundation Science Award (2021). He is currently leading a large research group consisting of members from various disciplines, graduate students and engineers and to bridge different disciplines (Energy, Nanotechnology, Applied Physics, Bioengineering, Biochemistry, Mechanical Engineering). He has been successful to secure funding for his research activities from a wide variety of national and international resources. He also serves as a Subject Editor in the Applied Thermal Engineering journal. He is the Co-director of Center of Excellence for Functional Surfaces and Interfaces for Nano diagnostics (EFSUN) and a Distinguished Researcher of Sabanci University Nanotechnology and Application Center and is a Member of Turkish Academy of Sciences (TÜBA).
Title: System and Component Level Challenges in Thermochemical Energy Storage
Abstract: Thermochemical storage systems can enable high energy density, long duration storage at temperatures spanning from building space heating to utility scale power generation. Significant effort has been focused on the development of new material systems. However, there has been less attention on the practical system- and component-level issues of integrating these materials into energy storage technologies. Thus, the objective of this talk is to present research on the thermal engineering challenges of implementing these materials in energy storage systems. We will focus on (1) the use of redox-active metal oxide particles for enabling high temperature thermal storage coupled to closed power cycles, and (2) the use of salt hydrate materials in closed and open systems for providing thermal storage and thermal amplification when integrated with heat pump systems. Our initial results show opportunity for the collaborative co-design and optimization of thermochemical energy storage technology from the material to system scale to maximize efficiency and minimize costs.
Bio: Dr. Brian Fronk is an Associate Professor in the Department of Mechanical Engineering at The Pennsylvania State University. From 2014-2022 he was an Assistant and then Associate Professor of Mechanical Engineering at Oregon State University. He received his Ph.D. and M.S. in Mechanical Engineering from the Georgia Institute of Technology, and his B.S. from the Pennsylvania State University.
His research interests include solar thermal power generation and chemical processing, energy storage, building energy systems, application of advanced manufacturing to novel heat and mass transfer devices, and the experimental investigation of multiphase and supercritical heat transfer. He has held a prior position at Carrier Corp., where he worked in the areas of CO2 compression and transport refrigeration. He is the recipient of an NSF CAREER award, the 2017 ASHRAE New Investigator Award, and the Oregon State University International Service Award. He is a registered professional engineer in the State of Oregon.
Title: Wildland fire: how did we get here and the thermo-fluid research needed
Abstract: Impacts from wildland fires have seemingly only increased as wildfires now routinely make headlines, pump smoke across the continent, and burn more structures and area every year. This talk will begin by introducing the causes of the current “wildfire problem” in the U.S.: the growth of the Wildland-Urban Interface (WUI), climate change, and the more than one hundred years of fire exclusion from the landscape. Our history of wildland fire relates to both the cause and the cure for the current “wildfire problem”. The path forward requires accepting that wildland fires will, and should, happen, but it needs to be the right kind of fire under the right conditions. Unfortunately, fundamental understanding of the processes controlling wildland fire behavior is lacking and this limits our ability to safely train our firefighters, predict fire behavior, and understand how to mitigate its effects. An overview of the current work at the Missoula Fire Sciences Lab to address this lack of understanding will be given, highlighting the important role of thermal and fluid dynamics in wildfire behavior. However, much more work needs to be done before we have confidence in our prediction capabilities and be able to reduce the impact of wildland fire on our communities. The talk will conclude with a discussion of these outstanding research needs.
Bio: Sara McAllister earned her Ph.D. in Mechanical Engineering in 2008 from the University of California, Berkeley. Her Ph.D. dissertation, sponsored by NASA, focused on material flammability in spacecraft. Since 2009, she has been a Research Mechanical Engineer with the U.S. Forest Service at the Missoula Fire Sciences Laboratory in Missoula, Montana. As part of the National Fire Decision Support Center, Sara’s research focuses on the fundamental governing mechanisms of wildland fire spread. Specifically, her research includes understanding the critical conditions for solid fuel ignition, flammability of live forest fuels, ignition due to convective heating, and fuel bed property effects on burning rate. She has authored two textbooks, one on combustion fundamentals and one on wildland fire behavior, as well as over 80 peer-reviewed publications and conference papers. In her spare time, Sara enjoys cycling, running, and racing in triathlons.