Affiliation: Emeritus Scientist, National Institute of Standards and Technology, Department of Fire Protection Engineering, University of Maryland, and a NIST Fellow

Title: Simulating Fire Effects in Large Buildings

Abstract: The purpose of this lecture is to assess the current state of our ability to simulate the consequences of a fire in a large building, and suggest some areas where improvement is needed. Attention is focused on the coupling of fire dynamics simulations and heat transfer analyses to each other and to structural analyses of the damaged building. The methodology used in the National Institute of Standards and Technology (NIST) investigation into the collapse of the World Trade Center Towers will be described from this perspective.

An overview of the NIST Fire Dynamics Simulator (FDS), the worlds most widely used CFD based tool for simulating fires is presented. The model employs a number of simplifications of the governing equations that allow for relatively fast simulations of practical fire scenarios. The hydrodynamic model consists of the low Mach number large-eddy simulation sub-grid closure with either a constant or dynamic coefficient eddy diffusivity. Combustion is typically treated as a mixing- controlled, single-step reaction of fuel and oxygen. The radiation transport equation is written in terms of a spectrally-averaged grey gas. Applications of the model include the design of fire protection systems in buildings and the reconstruction of actual fires.

The techniques used to couple the fire simulation to a detailed thermal analysis of the building structure and to perform that analysis are considered next. The coupling is non-trivial not only due to the complexity of the codes employed, but also due to large disparities in the length and time scales on which flow and thermal phenomena evolve. The temperature distribution in the load bearing structural elements in all floors of the buildings affected by the fire were calculated using the commercial code ANSYS, because it has the ability to perform both thermal and structural analyses in complex geometries, and because NIST structural analysts were familiar with its use.

Finally, limitations in both the simulation tools and the strategies used to apply them to the scenario under study are discussed. Research needs are emphasized by examination of some basic problems in fire–structure interactions. Although some of these limitations are being addressed, much work remains to be done. The intent of the lecture is not to summarize the results of the investigation, but rather to provide a specific context that illustrates the strengths and weaknesses of the methodologies employed.

Bio: Dr. Howard R. Baum is a NIST Fellow in the Engineered Fire Safety Group of the Fire Research Division (FRD) of the Engineering Laboratory (EL) at the National Institute of Standards and Technology (NIST). Dr. Baum has research interests in the fluid mechanics of fires, turbulent combustion, convective and radiative heat transfer, smoke transport, and microgravity combustion. He was a Lecturer and then Assistant Professor in the Division of Engineering and Applied Sciences at Harvard University from 1964 to 1971. He then spent four years as a Senior Scientist at Aerodyne Research, Inc., Billerica, Massachusetts before joining NIST.

Dr. Baum has published over one hundred forty papers and reports. His analysis of ventilation in containership holds is the technical basis of an international standard for containership ventilation. He is the co-developer (with R. Rehm) of what are now known as the low Mach number combustion equations, the starting point for most theoretical and computational work in that field. He has been involved in the development of large eddy simulation models for both building and outdoor fires at NIST since its inception. He also developed the first multiple fire model for urban environments that actually distinguishes individual fires.

Dr. Baum has served on National Research Council Panels convened by the Naval Studies Board in 1986 and 1991 to consider Office of Naval Research Opportunities in Solid and Fluid Mechanics, and a Panel in 1987 to consider the Status of Nuclear Winter Research. He was a member of the U.S. Delegation to the 1991 Japan-U.S. Heat Transfer Joint Seminar, and an invited participant in the 1994 U.S. Japan Seminar "Modeling in Combustion Science" sponsored by the National Science foundation and the Japan Society for the Promotion of Science. He was an invited lecturer at the SIAM Sixth International Conference on Numerical Combustion in 1996, at the 50th anniversary symposium of the National Research Institute of Fire and Disaster in Japan in 1998, and at the Emmons Memorial Symposium in San Antonio in 2000. He was also a member of the U.S. Panel of the UJNR Panel on Fire Research and Safety at the 13th meeting in 1996, the 14th meeting in 1998, and the 15th meeting in 2000. He was a Senior Visitor at the University of Minnesota Institute for Mathematics and its Applications (IMA) in 1999 and organizer of the IMA Fire Modeling Workshop. He is currently a member of the Editorial Board of the journals Combustion and Flame and Combustion Theory and Modeling.

Dr. Baum has been the recipient of many honors and awards. They include the U.S. Department of Commerce Silver Medal Award in 1981 and a Gold Medal Award in 1985. He was named Russell Severance Springer Visiting Professor at the University of California, Berkeley in 1985. He was awarded a Japan Society for the Promotion of Science Fellowship in 1994 for a visit to the University of Tokyo Institute of Industrial Science. He received the Medal of Excellence from the International Association for Fire Safety Science in 1991 and 1999. He was awarded the 1999 Arthur B. Guise Medal of the Society of Fire Protection Engineers. He was elected a Fellow and Chartered Physicist of the Institute of Physics in 1999. Dr. Baum was elected to membership in the National Academy of Engineering in 2000. His biography is listed in American Men and Women of Science, and Who's Who in America.

Affiliation: Senior Engineering Associate, Advanced Modeling and Analysis at Corning Incorporated

Title: Modeling Thermal and Fluids Problems Arising in Industry

Abstract: As computational capability continues to dramatically increase, we are able to support experimentation and analysis of manufacturing processes with practical but evermore detailed numerical models. This talk explores real-life thermal and fluids problems arising in the variety of businesses at Corning Incorporated, including the manufacture of catalytic converters for pollution control, optical fibers for telecommunication, and flat glass panels both large and small for displays. The problems include extrusion, the chemical reactions involved in the firing of ceramics, combustion synthesis and particle deposition, and drawing and forming of molten glass. As in other companies, development times are being shortened by incorporating analysis and modeling to drive testing and early experiments; in addition, process improvement and optimization benefits from the increased emphasis on fundamentals and a science-based approach.

Bio: John Abbott is a Senior Engineering Associate at Corning Incorporated. After finishing a B.S. in math from Caltech in 1974, he earned a Ph.D. in applied math at MIT with a dissertation in the area of nonlinear waves. Starting at Corning in 1979, he has worked on process engineering and fundamentals for a broad spectrum of Corning businesses, and has US and foreign patents in areas related to process, measurements, and product design. For 15 years he was in the division engineering group for Optoelectronics, focusing on the manufacturing process for optical fibers for telecommunications and the performance of the final fiber in optical links. Most recently he has contributed to improvements in manufacturing and measurements for glass designed for LCD displays and Gorilla Glass ® used in displays for handheld devices.

Affiliation: William F. Ward Sr. Distinguished Professor of Engineering at the Department of Mechanical Engineering, Whiting School of Engineering, at Johns Hopkins University

Title: Common Features in the Flow Structure and Turbulence of Tip Leakage Flows in Axial Turbomachines

Abstract: Tip leakage flows adversely affect the overall performance of axial turbomachines, and are major contributors to noise, vibrations, onset of stall in compressors, and cavitation breakdown in pumps. Consequently, considerable efforts have already been invested in studying them, and developing techniques to alleviate these undesirable effects. Measurements of flow within rotating machinery have been a challenge due to limitations in visual access to the interior of rotor passages and reflections from boundaries. We have resolved this problem by constructing a unique facility, in which the refractive index of transparent rotor is matched with that of the fluid – a concentrated aqueous solution of sodium iodide. This arrangement facilitates unobstructed flow measurement at any point within the machine using 2D, stereo, holographic and tomographic particle image velocimetry (PIV). This presentation focuses on common features in the flow structure and turbulence in the tip region of several axial turbomachines. They have been observed in a series of experiments performed within machines with different sizes, speeds, load distributions and tip-gap sizes. These observations follow the evolution of the backward leakage flow across the narrow tip gap, its rollup into a tip leakage vortex (TLV) near the suction side of the blade, and the dynamics of this vortex within the rotor passage. Several notable phenomena include: (i) in instantaneous realizations, the vicinity of the TLV center contains multiple interlacing structures that never roll up into a single vortex; (ii) the TLV migrates from the suction side of one blade to the pressure side of the neighboring blade; (iii) vortex breakup/bursting occurs in regions of adverse pressure gradients, rapidly spreading TLV fragments over substantial fraction of the tip region; (iv) Endwall casing boundary layer separation occurs when the leakage flow meets the main passage flow, feeding counter rotating vorticity into a layer that surrounds the TLV center; (v) the (anisotropic and inhomogeneous) turbulence levels are high in the shear layer connecting the TLV to the suction-side corner of the blade, near the TLV center, and in the region of endwall boundary layer separation. Specific mechanisms dominating the turbulence production will be introduced and discussed.

Bio: JOSEPH KATZ received his Ph.D. and M.S. from the California Institute of Technology and his B.S. at the Tel-Aviv University. He is the William F. Ward Sr. Distinguished Professor of Engineering at the Department of Mechanical Engineering, Whiting School of Engineering, at Johns Hopkins University. He is Director and co-Founder of the Center for Environmental and Applied Fluid Mechanics (CEAFM) at JHU, and he manages the Laboratory for Experimental Fluid Dynamics, and the new Hopkins Heart Initiative. Dr. Katz also serves as the Chair, Board of Journal Editors of the American Society of Mechanical Engineers (ASME). He is a Fellow of ASME and of the American Physical Society (APS), as well as a JHU Gilman Scholar. He has advised numerous graduate students and post-docs, most of which currently hold academic, industrial and government research positions around the world. He has received several awards including the 2004 ASME Fluids Engineering Award, and several best paper awards. Dr. Katz research extends over a wide range of fields, with a common theme involving experimental fluid mechanics, and development of advanced optical diagnostics techniques for laboratory and field applications. His research groups has studied laboratory and oceanic boundary layers, flows in turbomachines, flow induced vibrations, behavior of marine plankton in the laboratory and in the ocean, as well as multiphase flows, including cavitation, bubble, and droplet dynamics in turbulent flows. He has co-authored more than 320 Journal and conference papers.

Affiliation: Professor and Chair of the Food Science Dept. at Rutgers, and a Fellow of Institute of Food Technologists.

Title: Thermal Transport in Selected Food Processing Operations

Abstract: Many food processing operations involve application of heat to process foods for making them safer to consume or to impart specific organoleptic attributes such as color, flavor, etc. This presentation will give an overview of the current state of knowledge of thermal transport in selected food processing operations such as batch and continuous microwave processing, hybrid jet impingement-microwave baking, ohmic heating, aseptic processing, extrusion, and high pressure processing. Results obtained from mathematical models and numerical simulations, including their limitations and experimental challenges will be discussed.

Bio: Dr. MUKUND V. KARWE is a Professor of Food Engineering and the Dean of International Programs at the School of Environmental and Biological Sciences of Rutgers University, New Jersey. Over the last three decades, Dr. Karwe’s research has covered areas such as Food Extrusion, Microwave and Hybrid Baking, Fortification of Foods with Omega-3 fatty acids, High Pressure Food Processing, Effect of Processing on Nutraceuticals in Foods, Cold Plasma Processing, and Flow of Food in human GI tract. He has published over 110 research articles and book chapters, including one co-edited book. His research has been supported by USDA, US Army, and Food Industry. Dr. Karwe has given research seminars in Argentina, Australia, Brazil, China, France, Greece, India, Italy, Kuwait, S. Korea, Turkey, and UK. Dr. Karwe is a fellow of the Institute of Food Technologists (IFT) USA, and a recipient of IFT’s highest Teaching Excellence award.

Affiliation: Professor of aeronautics and astronautics and of mechanical engineering, Center for Turbulence Research, Department of Mechanical Engineering, Stanford University

Title: Simulations of Shock-Turbulence Interactions: From Canonical Problems to Engineering Applications

Abstract: Many applications in engineering and physical sciences involve situations where a turbulent flow interacts with shock waves. High-speed flows around aerodynamic bodies and through propulsion systems for high-speed flight are bound with interactions of shear-driven turbulence with complex shock waves. Prediction of shock-induced separation, unsteady loads and heat-transfer in such systems is a significant engineering challenge. Numerical simulations of such physical phenomena impose conflicting demands on the numerical algorithms. Capturing broadband spatial and temporal variations in a turbulent flow suggests the use of high-bandwidth schemes with minimal dissipation and dispersion, while capturing a flow discontinuity at a shock wave requires numerical dissipation. Results from DNS of a canonical shock-turbulence interaction problem, i.e. the interaction of isotropic turbulence with a (nominally) normal shock, are discussed first, highlighting the effect of shock strength and turbulence intensity, and contrasted with linear theory where possible. Significant non-linear effects in the post-shock region are observed and explored. Results from the interaction of a spherical blast wave and a converging shock wave with turbulence will be contrasted with the planar problem. Finally as a bridge from simpler, idealized cases of shock-turbulence interaction to applications in engineering, some highlights from LES of jet injection and mixing in a supersonic crossflow, oblique shock wave interaction with a turbulent boundary layer, supersonic flow in a compression ramp, and shock-induced unsteadiness in an over-expanded nozzle will be discussed. The physical insights enabled by DNS and LES of high-speed compressible turbulent flows will be emphasized and open questions and modeling issues discussed along the side.

Bio: Professor Lele's research combines numerical simulations with analytical modeling to study fundamental unsteady flow phenomena, turbulence, flow instabilities, and flow-generated sound. Recent projects include shock-turbulence interaction, exploitation of flow instabilities for enhanced mixing and for reducing the vortex-wake hazard from an airplane, new approaches for active noise control, and the development of high-fidelity prediction methods for engineering applications.

Affiliation: Distinguished Professor of Chemical Engineering Director of the CUNY Energy Institute, The City College of New York

Title: Heat and Mass Transfer across Turbulent Gas-Liquid Interfaces

Abstract: Scalar exchange between turbulent gas and liquid streams separated by deformable and breaking interfaces is of central importance in many environmental and industrial processes. For example, ocean uptake of greenhouse gases is largely governed by liquid-side mass transfer coefficients at the atmosphere water surfaces. Because measurements and analysis of fluid motion and scalar fields very close to deforming interfaces is difficult, our understanding of the governing phenomena is still poor compared to what we know about transport processes in solid-fluid boundary layers. We will discuss recent developments in direct numerical simulations and particle imaging velocimetry that have elucidated turbulence behavior at wavy gas-liquid surfaces. The results indicate that the surface renewal and surface divergence models, which are commonly used to parameterize liquid side controlled transfer rates are inadequate when interfaces micro-break. Theoretical approaches, which combine elements of the surface renewal and divergence models, will be discussed and compared with recent experimental data. The range of applicability of existing surface renewal small models will be discussed as well in the context of the new data.

Bio: SANJOY BANERJEE is a CUNY distinguished professor of chemical engineering and director of the CUNY Energy Institute, whose headquarters is at The City College of New York. The author of more than 190 articles, book chapters and refereed conference proceedings and the holder of four patents, he has a BS in chemical engineering from the Indian Institute of Technology and a PhD from the University of Waterloo in Canada. Until March 2008, Banerjee was professor above scale in the chemical engineering department, with joint appointments in the mechanical engineering department and the Bren School of Environmental Science, at the University of California, Santa Barbara, where he had been since 1980. Banerjee was vice chair of chemical engineering from 1982-84, chair from 1984-90 and is largely responsible for bringing the UCSB chemical engineering department into the top 10 in the country. Previously, he held appointments at the University of California, Berkeley, McMaster University in Canada and Atomic Energy of Canada, ultimately serving as its acting director of applied science. He is a member of the U.S. Advisory Committee on Reactor Safeguards, which is congressionally mandated to maintain oversight over nuclear power. He also is on the Reference Board of the Norwegian Govt.-Oil Industry Consortium for Oil-Gas Flow Assurance Project. Banerjee also helped to establish several companies based on research collaborations, including Metaheuristics LLC (www.metah.com), which develops highly parallelizable software aimed at very large fluid/thermal simulations, Mindflash Technologies (www.mindflash.com), which applies artificial intelligence techniques to learning systems software, and Gas Reaction Technologies Inc. (www.grt-inc.com), which uses novel metal oxide catalysts to convert natural gas to a variety of liquid products, including gasoline and benzene/toluene/xylene. These spinoffs are profitable, with GRT's being recently acquired by a major oil company. Banerjee also has served or serves as a consultant to several oil companies, including ExxonMobile (Houston), Shell (Amsterdam), Statoil (Stavanger), Det Norske Veritas (Oslo), Reliance (Mumbai) and ENI (Milano), as well as many chemical/pharma companies, including Hoffmann LaRoche, Novartis and Novo Nordisk (Denmark). He has helped these companies with technical and operational issues as well as high-level due diligence related to acquisitions and projects.

Affiliation: Associate chemical engineer at Eastman Chemical Company

Title: CFD Application to Large-Scale Industrial Multiphase Flows: Miracles Do Happen

Abstract: Specialized Eulerian-Eulerian modeling frameworks based in the commercial solver backbones Fluent and CFX are used extensively for reaction engineering within Eastman Chemical Company. Four examples will be elucidated: 1) optimization of a transonic three-stream self-sustaining pulsatile coaxial airblast injector, 2) mitigating thermal runaway in an evaporative trickle bed reactor with an external temperature control loop, 3) improving yield in a slurry bubble column oxidizer in heterogeneous flow with potential oxygen starvation, and 4) identifying mass transfer limitations in a dual-blade bubbly continuous stirred tank reactor. The unit operations involved in these studies represent very large scale process equipment and multi-million dollar annual revenue streams. Additionally, the physiochemical complexities and momentum sources associated with simulating these systems create strong non-linear coupling and stretch the bounds of available numerical recipes. Modeling risks abound; therefore, judicious and validated computational methods are essential. In each of these examples, methods and data used for anchoring CFD to process reality are provided. It is shown that although these models are not designed to incorporate the complete physical picture at all scales, they are capable of guiding designs and providing results that contribute to Eastman’s bottom line.

Bio: Wayne Strasser has provided solutions to problems related to fluids, reactions, and phase change for Eastman Chemical Company’s global sites for 20 years, resulting in increased energy utilization and improved product yield valued at tens of millions (USD) annually. The thrusts of his current research (PhD, Virginia Tech, 2015) include optimization of a transonic self-sustaining pulsatile airblast atomizer and hybrid RANS-LES modeling of primary atomization. He chaired the ASME Fluid Applications and Systems Technical Committee and currently serves on the ASME Honors and Awards Committee. He organizes two ASME symposia annually related to Industrial and Environmental flows, and he actively reviews articles for at least a dozen journals. He has 34 patents in the US, plus those abroad. He is a registered P.E. in three US states, an ASME Fellow, and operates a private CFD consulting company. He also enjoys lively philosophical debate on the origin and meaning of life.