Plenary Lectures
Aspects of Flow Boiling Characteristics in Small to Micro-Tubes and Channels
In the last few years advances in electronics and high power devices created a challenge for thermal engineers due to the generated high heat fluxes that need to be dissipated to enable efficient operation, maintain operating temperatures within design limits, and, in certain cases, avoid catastrophic failures. Flow boiling in micro scale heat exchangers located at these high heat flux devices offers one of the best possible cooling solutions. The advantages of these small to micro multichannel evaporators include: (1) Flow boiling can achieve very small temperature variations of the surface to be cooled (slightly above the fluid saturation temperature). This can reduce thermo-mechanical stresses and extend the life of the equipment. (2) High heat transfer coefficients due to flow and phase change. This can allow for the use of small pumps – reducing the size and power consumption of the overall thermal management system. (3) In regions where nucleate boiling dominates, the heat transfer coefficient increases with applied heat flux (load) and thus creates a responsive system. Past research in the development of small scale thermal management systems focused on microchannel evaporators. However, the design and size of the condenser can be equally important in certain applications and should be assessed as part of an integrated system.
Research in the above is currently pursued in laboratories across the world. However, there is still a number of fundamental/design issues that need to be resolved and concluded upon in order to proceed with a full adoption of these systems by industry. These include the definition of small and micro scales, the prevailing flow regimes and heat transfer mechanisms and the effect of parameters such as geometry (tubes and channels of different aspect ratios), material-fluid combinations and surface characteristics. The length of these microscale heat exchangers is small and hence the actual length of the channels is also important. In addition, in pumped integrated systems the degree of subcooling of the fluid leaving the condenser and entering the evaporator, can affect the heat transfer performance and pressure drop. Furthermore, flow instabilities and flow reversal must be evaluated and their effect on heat transfer rates assessed. Finally, design considerations must include recommendations to avoid dryout, with the resulting undesirable significant reduction in heat transfer rates.
The presentation will start with a discussion of possible applications of cooling using flow boiling in micro channel heat exchangers. The effect of the above parameters on flow patterns, heat transfer rates and pressure drop will then be presented. A large number of correlations/models predicting flow patterns, heat transfer rates and pressure drop has been published. These were evaluated and recommendations will be made for their adoption or further work. Finally, research into the design of fully integrated small scale pumped thermal management systems utilising a multichannel micro scale evaporator and water or air-cooled condensers will be presented.
Prof. Tassos G. Karayiannis
Brunel University London, UK.
Email: tassos.karayiannis@brunel.ac.uk
Tassos Karayiannis studied at the City University London and the University of Western Ontario. He started his career as a researcher at Southampton University and later as a British Technology Group Researcher at City University. Subsequently he worked at London South Bank University and joined Brunel University London in 2005 where he is now professor of Thermal Engineering and Leader of the Energy Efficient & Sustainable Technologies Theme. Professor Karayiannis has carried out fundamental and applied research in a number of heat transfer related topics including natural convection and renewable energy. He has been involved with two-phase flow and heat transfer for over 30 years. Initially he worked on the enhancement of pool boiling and condensation processes using high intensity electric fields (Electrohydrodynamic enhancement of Heat Transfer). In parallel, he carried out extensive experimental work in pool boiling heat transfer with plane and enhanced surfaces. Professor Karayiannis has also been very actively involved with research in flow boiling in small to micro tubes and micro-multi-channels. This work involves fundamental studies as well as research leading to the design of high heat flux integrated thermal management systems. He chairs the Int Conf on Micro and Nanoscale flows, now in its 6th edition. He is a Fellow of the EI and the IMechE, the Chairman of the UK National Heat Transfer Committee and a UK Representative on the Assembly for Int. Heat Transfer Conferences.
BIO
Dr Henrik Lund is Professor in Energy Planning at Aalborg University and Editor-in-Chief of Elsevier International journal ENERGY. For more than 25 years, his area of expertise has been energy system analysis, energy planning and energy economics. He is the author of more than 200 books and articles and on the Thomson Reuters list of the most highly cited researches in the world.Abstract
This lecture presents the learning of a series of studies that analyze the problems and perspectives of converting the present energy system into a 100 percent renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies including transportation and aviation. The typical smart grid sole focus on the electricity sector often leads to the definition of transmission lines, flexible electricity demands and electricity storage as the primary means to deal with the integration of fluctuating renewable sources. However, the nature of wind power and similar sources has the consequence that these measures are neither very effective nor cost-efficient. The most effective and least-cost solutions are to be found when the electricity sector is combined with the heating sector and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. This presentation illustrates why electricity smart grids should be seen as part of overall smart energy systems and with the case of Denmark illustrate how to design such future energy system.High-order simulations of shock-wave/boundary-layer interactions
Compressibility effects are present in many practical turbulent flows, ranging from shock-wave/boundary-layer interactions on the wings of aircraft operating in the transonic flight regime to supersonic and hypersonic engine intake flows. Besides shock wave interactions, compressible flows have additional dilatational effects and, due to the finite sound speed, pressure fluctuations are localized and modified relative to incompressible turbulent flows. Such changes can be highly significant, for example the growth rates of mixing layers and turbulent spots are reduced by factors of more than three at high Mach number, but can be partly explained using simple flow instability concepts. An increasing number of such flows can be reliably simulated nowadays using direct numerical simulation or large eddy simulation, based on hybrid high-order finite difference and shock-capturing schemes. As an example we will take a recent simulation of transonic buffet on an airfoil at Re=500,000. We will also show examples of code performance on various high performance computing architectures, focusing on the recently-developed OpenSBLI code-generation framework. Finally, we will consider a fully three-dimensional problem of shock-wave/boundary-layer interaction in a closed duct, considering direct effects of shock waves, due to their penetration into the outer part of the boundary layer, as well as indirect effects due to the high convective Mach number and shock-induced shear-layer curvature. Two-point correlations are used to explore the connections between the corner and central separation zones. An important observation is that the low-frequency shock-induced unsteadiness is found to be uncorrelated, implying a more localized mechanism leading to low-frequency unsteadiness in each separation region separately.
Prof. Neil Sandham
Faculty of Engineering and the Environment (Aero/Astro) University of Southampton, UK.
Neil Sandham (Southampton) has been Professor of Aerospace Engineering at the University of Southampton since 1999, having previously been at Stanford University (PhD 1989), DLR Göttingen and Queen Mary, University of London. His area of expertise is DNS and Large-Eddy Simulation (LES) of transitional and turbulent flows over the full range of speeds from incompressible to hypersonic, with current projects in transonic airfoil flows, flow over surface roughness and intake aerodynamics. He was the founding principal investigator of the UK Turbulence Consortium. From 2014 to 2017 he was Head of Aeronautics, Astronautics and Computational Engineering the University of Southampton. He is an Associate Editor of Computers and Fluids and AIAA Journal.
Abstract
Energy its efficient use in production is key to ensuring the healthy functioning of the world economies. Climate change, together with the haze in growing megalopolises, and water scarcity in many areas are the key environmental challenges of our time. Polluted air and water, especially in places with high population density and high resource demands, have been posing an increasing threat to the mankind. To solve those issues, a complex thinking is very much needed. Traditionally, the involvement of process, mechanical and chemical engineering was considered as a cornerstone of a successful outcome. The close and strategic collaboration from most fields is a strong requirement. The complex systems thinking requires a close synergy of technologists, managers and economists, policymakers and politicians and related social scientists. In this context, ensuring cleaner energy is the necessary condition for cleaner production, especially for reducing the emissions of greenhouse gases and other pollutants, which are directly related to the types and loads of the energy sources used.Introduction
They are various emerging methodologies of sustainability assessment. The footprint methodology is one of gaining considerable attention. Greenhouse gases (ghg – rather than just carbon) footprint becomes a widely accepted environmental accounting tool for business managers, policy makers and non-governmental organisations, attempting to identify mitigation measures that reduce the threat of climate change. The industry is increasingly engaged as a part of policy development and product design.ANALYSIS AND MODELLING
As an illustrative case study of a toll following complex systems thinking presents the development of Process Integration. It originated from Heat Integration to target the minimum heat requirements and following the demand being extended to Total Sites, Locally Integrated energy systems and even to self-sufficient regions methodology. To cover the complexity with wider scope targeting GHG and haze creating emissions, integration of renewable energy sources, biofuels, waste and effluents supply chains, investment, property and material recovery targeting.RESULTS AND DISCUSSION
The presentation will be concluded by suggestions for future research and the discussion and exchange of ideas are most welcome.BIO
Prof Dr-Hab Jiří Jaromír KLEMEŠ, DSc Head of
“Sustainable Process Integration Laboratory – SPIL”, NETME Centre, Faculty of
Mechanical Engineering, Brno University of Technology - VUT Brno, CZ and
Emeritus Professor at “Centre for Process Systems Engineering and
Sustainability”, Pázmány Péter Catholic University, Budapest, and at FIT,
Pannonia University, Veszprem, HU. Previously the Project Director, Senior Project Officer and Hon Reader at Department of Process Integration at UMIST, The University of Manchester and the University of Edinburgh, UK. Founder and a long-term Head of the Centre for Process Integration and Intensification – CPI2, University of Pannonia, Veszprém, Hungary. Awarded by the EC with Marie Curie Chair of Excellence (EXC). Track record of managing and coordinating 93 major EC, NATO and UK Know-How projects. Research funding attracted over 23 M€.
Co-Editor-in-Chief of Journal of Cleaner Production and Chemical Engineering Transactions, Subject Editor of ENERGY and Emeritus Executive Editor of Applied Thermal Engineering. The founder and President of 22 y of PRES (Process Integration for Energy Saving and Pollution Reduction) conferences. Chairperson of CAPE Working Party of EFCE, a member of WP on Process Intensification and of the EFCE Sustainability platform. He authored and coauthored over 400 papers, h-index reaching 50. A number of books published by Elsevier, Woodhead, McGraw-Hill; Ashgate Publishing Cambridge; Springer; WILEY-VCH; Taylor & Francis).
Several times Distinguished Visiting Professor at Universiti Teknologi Malaysia and University Technology Petronas, Malaysia; Xi’an Jiaotong University; the South China University of Technology, Guangzhou and Tianjin University in China; University of Maribor, Slovenia; the Brno University of Technology and the Russian Mendeleev University of Chemical Technology, Moscow. Doctor Honoris Causa of Kharkiv National University “Kharkiv Polytechnic Institute” in Ukraine, the University of Maribor in Slovenia, University POLITEHNICA Bucharest, Romania. “Honorary Doctor of Engineering Universiti Teknologi Malaysia”. Awarded with “Honorary Membership of Czech Society of Chemical Engineering", "European Federation of Chemical Engineering (EFCE) Life-Time Achievements Award" and "Pro Universitaire Pannonica" Gold Medal.
On the Structured Convection
Natural convection driven by heating patterns is referred to as the structured convection. Its understanding is required for a reliable prediction of the local contaminant transport in urban environments where the form of the convection is dictated by the surface topography (building pattern) and thermally-relevant features of this topography like color variations (color patterns of roofs, streets and parks). Similar conditions can be encountered in rural environments where local circulation can be driven by different heating rates of patterns of forests and lakes, and can be significantly modified by the rural terrain topography. Heating patterns can be used to induce proper structure in the flow to improve mixing and thereby would provide an excellent tool to design efficient heat exchangers. Other examples include patterns of local fires, patterns of computer chips, thermal patterning in micro-fluidic devices, and so on. The important unifying features of all these problems is the existence of a certain spatially distributed pattern of external heating applied to the system of interest. The structured convection occurs in systems heated from below as well as in systems heated from above. It occurs regardless of the intensity of heating and thus is of interest in system with small temperature differences. A review of the recent results will be presented with focus on the super-thermo-hydrophobic effect which provides means for drag reduction.
Prof. Jerzy M Floryan
Department of Mechanical and Materials Engineering, the University of Western Ontario in Canada, Canada.
Email: floryan@uwo.ca
Dr. Jerzy M Floryan is a Professor at the Department of Mechanical and Materials Engineering, the University of Western Ontario in Canada. He received PhD from Virginia Tech, US, and postdoctoral training from the Northwestern University, USA. He is Fellow of the American Society of Mechanical Engineers, Canadian Society of Mechanical Engineers, Canadian Aerospace and Space Institute, Engineering Institute of Canada, Japanese Society for the Promotion of Science and American Physical Society, and Associate Fellow of the American Aeronautics and Space Institute. He has been awarded Humboldt Research Prize in Germany, Senior NATO Research Award in France, Science and Technology Fellowship in Japan and Lady Davis Fellowship in Israel. His Canadian awards include Robert W. Angus Medal (Engineering Institute of Canada) and Canadian Pacific Railway Engineering Medal (Canadian Society of Mechanical Engineers). He is Canadian delegate to the International Union of Theoretical and Applied Mechanics (IUTAM). Dr. Floryan held visiting appointments at the Los Alamos National Laboratory (US), German Aerospace Research Establishment (DVLR, Gottingen, Germany), French Aerospace Research Establishment (CERT-ONERA, Toulouse, France), National Aerospace Laboratory (Tokyo, Japan), Paul Sabatier University (Toulouse, France), Ohio University (USA), National University of Singapore (Singapore) and Beijing Institute of Technology (China). He is serving at present as the President of the Canadian Society for Mechanical Engineering.
Abstract
A tremendous effort has been devoted to improving the energy efficiency of home appliances around the world over the past 2 decades, where the adoption of energy labelling, and the enforcement of Minimum Energy Performance Standards (MEPSs) have led to significant energy savings. These efforts are continuing to bring innovation in refrigerator cabinet (i.e. advanced insulation, improved gaskets), sealed refrigeration system (e.g. low GWP refrigerants, efficient fans, compressors and heat exchangers, adaptive defrosts etc.), user-friendly features (e.g. double doors, internet connectivity, on-line access, internal cameras, music/TV) and legislative improvements enforcing more stringent MEPSs. Increased global competition and improved energy efficiency policies of various governments are responsible for bringing innovation into user friendly product development where more energy efficient products are now appearing in the market. The talk will present an overview of some of the recent advancements including novel/alternative technologies that are responsible for the development of energy efficient household refrigerators.BIO
Dr. Bansal currently works for Viking
Range, Middleby Corporation (USA) as their R&D Lead of Energy Efficiency and
Refrigeration. Previously he worked at Oak Ridge National Laboratory (USA) as
Distinguished R&D Scientist during 2010-15, and the University of Auckland
(New Zealand) as Professor (Personal Chair) of Mechanical Engineering and
Associate Dean Postgraduate of the Faculty of Engineering during 1988-2012. He
has presented numerous plenaries and published over 260 technical papers and
three books. He is a Fellow of ASHRAE and Vice-President of Commission B1 of the
International Institute of Refrigeration. He is currently serving as an
Executive Editor of Applied Thermal Engineering, and Associate Editor of J.
Science and Technology for the Built Environment (previously HVAC&R), and J.
of Process Mechanical Engineering (IMechE, UK).Mass Transfer from Clean and Contaminated Bubbles in a Vertical Pipe
Mass transfer from a bubble plays an important role in many industrial processes such as bubble columns and sequestration of carbon dioxide in ocean. Though many studies have been carried out to understand heat and mass transfer from a bubble (Clift et al. 1978), our understanding is still rudimentary especially on effects of surface-active agents, electrolyte and pipe walls on the mass transfer rate. Hence in my laboratory experimental and numerical studies on mass transfer from clean and contaminated bubbles in vertical pipes have been carried out for a decade (Abe et al. 2008; Aoki et al, 2015a, 2015b, 2017; Hayashi et al., 2011, 2014; Hori et al., 2017; 2019; Hosoda et al., 2014, 2015; Kastens et al., 2015). A review of these studies will be made in the presentation, i.e. reviews on (1) mass transfer from clean ellipsoidal and Taylor bubbles, (2) effects of shape oscillation on mass transfer from a Taylor bubble, (2) effects of surfactants with low and high Hatta numbers on mass transfer, (3) effects of carbon-chain lengths of higher alcohols on mass transfer, (4) effects of electrolyte and (5) combined effects of electrolyte and surfactants.
Prof. Akio Tomiyama
Graduate School of Engineering, Kobe University, Japan.
Email: tomiyama@mech.kobe-u.ac.jp
Akio Tomiyama is Professor at Kobe University since 2003. He obtained his PhD from Tokyo Institute of Technology. He was formerly Researcher at the Energy Research Laboratory at Hitachi Ltd. between 1984 and 1988, then Research Associate (1988-1991) and Associate Professor (1991-2002) at the Kobe University. He has served as the Dean of the Graduate School of Engineering, Kobe University from 2015 to 2019. His areas of expertise are multi-scale CFD for multiphase flows, experiments and modeling of bubble dynamics and turbulent dispersed multiphase flows. He has 290 papers in refereed journals and over 300 papers in international conferences. Prof. Tomiyama has been an associate editor of International Journal of Multiphase Flow for 14 years, and is the Editor-in-Chief of Multiphase Science and Technology, a member of editorial advisory board of International Journal of Heat and Fluid Flow, that of Journal of Computational Multiphase Flows and Vice-Chair of the Virtual International Research Institute of Two-Phase Flow and Heat Transfer. He has also served as the President of Japanese Society for Multiphase Flow, a Governing Board Member of International Conference on Multiphase Flow (ICMF), the Scientific Secretary of 5th ICMF, a member of the international scientific committee in 3rd to 6th ICMF, and the Co-Chairperson of 3rd to 7th European-Japanese Two-Phase Flow Group Meetings.
BIO
Dr Henrik Lund is Professor in Energy Planning at Aalborg University and Editor-in-Chief of Elsevier International journal ENERGY. For more than 25 years, his area of expertise has been energy system analysis, energy planning and energy economics. He is the author of more than 200 books and articles and on the Thomson Reuters list of the most highly cited researches in the world.Abstract
This lecture presents the learning of a series of studies that analyze the problems and perspectives of converting the present energy system into a 100 percent renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies including transportation and aviation. The typical smart grid sole focus on the electricity sector often leads to the definition of transmission lines, flexible electricity demands and electricity storage as the primary means to deal with the integration of fluctuating renewable sources. However, the nature of wind power and similar sources has the consequence that these measures are neither very effective nor cost-efficient. The most effective and least-cost solutions are to be found when the electricity sector is combined with the heating sector and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. This presentation illustrates why electricity smart grids should be seen as part of overall smart energy systems and with the case of Denmark illustrate how to design such future energy system.current research directions in the field of computational particle-laden flows
The presentation will survey some current research directions in the field of computational particle-laden flows, such as double-diffusive sedimentation, grain-resolving simulations of cohesive and non-cohesive sediment transport, and salt crystal precipitation in hypersaline lakes. Open questions and future research directions will be outlined.
Prof.
Department of Mechanical Engineering,University of California
Santa Barbara, USA.
Email: meiburg@engineering.ucsb.edu
Professor Meiburg is the director of Center for Interdisc. Research in Fluids in UCSB and was the chair of Mechanical Engineering in UCSB form 7/03 to 6/07. Professor Meiburg's research interests lie in the general area of fluid dynamics and transport phenomena. He has been awarded Presidential Young Investigator Award (1990), Humboldt Senior Research Award (2005), Senior Gledden Fellowship in Institute of Advanced Studies in University of Western Australia (2008), Lorenz G. Straub Award Keynote Speaker in University of Minnesota (2012). He was elected fellow of American Physical Society in 2009 and fellow of ASME in 2013, He worked as a Shimizu Visiting Professor in Stanford University in 2016-17 and Ronald F. Probstein Lecture in MIT in 2018. In 2017-18, he was elected as the chair Division of Fluid Dynamics, American Physical Society.
BIO
Dr Henrik Lund is Professor in Energy Planning at Aalborg University and Editor-in-Chief of Elsevier International journal ENERGY. For more than 25 years, his area of expertise has been energy system analysis, energy planning and energy economics. He is the author of more than 200 books and articles and on the Thomson Reuters list of the most highly cited researches in the world.Abstract
This lecture presents the learning of a series of studies that analyze the problems and perspectives of converting the present energy system into a 100 percent renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies including transportation and aviation. The typical smart grid sole focus on the electricity sector often leads to the definition of transmission lines, flexible electricity demands and electricity storage as the primary means to deal with the integration of fluctuating renewable sources. However, the nature of wind power and similar sources has the consequence that these measures are neither very effective nor cost-efficient. The most effective and least-cost solutions are to be found when the electricity sector is combined with the heating sector and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. This presentation illustrates why electricity smart grids should be seen as part of overall smart energy systems and with the case of Denmark illustrate how to design such future energy system.Development of Advanced Experimental Techniques for Thermal-Fluid Dynamics Studies
The talk will start with the description of the recent progress made by the speaker in developing a novel molecule-based flow diagnostic technique, named as Molecular Tagging Velocimetry and Thermometry (MTV&T), for simultaneous measurements of flow velocity and temperature distributions in fluid flows. Unlike most commonly-used particle-based flow diagnostic techniques such as Particle Image Velocimetry (PIV), MTV&T utilizes specially-designed phosphorescent molecules, which can be turned into long-lasting glowing marks upon excitation by photons of appropriate wavelength, as the tracers for both flow velocity and temperature measurements. The unique glamour of the MTV&T technique will be demonstrated from the application examples to study the thermal effects on the wake instabilities behind a heated cylinder, to quantify of the transient behavior of electroosmotic flows in electrokinetically-driven microfluidics, and to visualize the unsteady heat transfer and phase changing process within micro-sized icing water droplets pertinent to aircraft icing and de-/anti- icing applications. A novel structure-light based digital image projection (DIP) technique will also be introduced to achieve quantitative measurements of the droplet/film thickness distributions to quantify the dynamic impact process of water droplets onto solid surface with different impact velocities and surface wettability. Based on the time-resolved DIP measurements, the time evolution of the droplet shapes in the course of the dynamic impact process, i.e., the spreading, receding, and oscillating of the impinging droplets, under different test conditions are revealed clearly and quantitatively. The quantitative measurements are very helpful to improve our understanding of the important micro-physical processes pertinent aircraft icing phenomena for the development of more effective anti-/de-icing strategies for aircraft icing mitigation.
Prof. Hui Hu
Department of Aerospace Engineering,Iowa State University, USA.
Email: huhui@iastate.edu
Dr. Hui Hu is the Martin C. Jischke Professor and Associate Dept. Chair of Aerospace Engineering at Iowa State University. He received his BS and MS degrees in Aerospace Engineering from Beijing University of Aeronautics and Astronautics (BUAA) in China, and a PhD degree in Mechanical Engineering from the University of Tokyo in Japan. His recent research interests include advanced flow diagnostics; aircraft icing physics and anti-icing/de-icing technology; liquid fuel atomization and spray flow characterization; film cooling and thermal management of gas turbines; wind turbine aerodynamics and rotorcraft aeromechanics; micro-flows and micro-scale heat transfer in microfluidics. Dr. Hu is an ASME Fellow and AIAA Associate Fellow, and is serving as an editor of “Experimental Thermal and Fluid Science-Elsevier” and an associate editor of “ASME Journal of Fluid Engineering”. Dr. Hu received several prestigious awards in recent years, including 2006 NSF-CAREER Award, 2007 Best Paper in Fluid Mechanics Award (Measurement Science and Technology, IOP Publishing), 2009 AIAA Best Paper Award in Applied Aerodynamics, 2012 Mid-Career Achievement in Research Award of Iowa State University, 2013 AIAA Best Paper Award in Ground Testing Technology, and 2014 Renewable Energy Impact Award of Iowa Energy Center. Further information about Dr. Hu’s technical background and recent research activities is available at: http://www.aere.iastate.edu/~huhui/
BIO
Dr Henrik Lund is Professor in Energy Planning at Aalborg University and Editor-in-Chief of Elsevier International journal ENERGY. For more than 25 years, his area of expertise has been energy system analysis, energy planning and energy economics. He is the author of more than 200 books and articles and on the Thomson Reuters list of the most highly cited researches in the world.Abstract
This lecture presents the learning of a series of studies that analyze the problems and perspectives of converting the present energy system into a 100 percent renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies including transportation and aviation. The typical smart grid sole focus on the electricity sector often leads to the definition of transmission lines, flexible electricity demands and electricity storage as the primary means to deal with the integration of fluctuating renewable sources. However, the nature of wind power and similar sources has the consequence that these measures are neither very effective nor cost-efficient. The most effective and least-cost solutions are to be found when the electricity sector is combined with the heating sector and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. This presentation illustrates why electricity smart grids should be seen as part of overall smart energy systems and with the case of Denmark illustrate how to design such future energy system.Drag reduction and heat transfer in turbulent channel flow over circular dimples: the shift of the deepest point of dimples
Dimples have shown reduction in drag and enhancement in heat transfer in turbulent channel flows. However a region of flow recirculation usually occurring at the upstream portion of the dimple limits this drag reduction and heat transfer enhancement. Although shallower dimples can minimise the flow recirculation that occurs, the amount of drag reduction and heat transfer enhancement is also limited due to the shallow dimple depth. A potential solution may be to shift the deepest point of the dimple downstream to reduce the upstream wall slope, thereby reducing the flow recirculation that occurs. Numerical results for circular non-axisymmetric dimples in a fully developed turbulent channel flow show that shifting the deepest point of the dimple downstream reduces the flow recirculation at the upstream portion at the expense of greater flow impingement at the downstream portion. This stronger flow impingement and increased fluid ejection at the downstream edge results in greater heat transfer enhancement. However, large shifts in the deepest point of the dimple downstream generates significant flow impingement and the accompanying form drag, resulting in increased drag and pressure loss. A parametric study is conducted to determine the optimal shifting of the deepest point to reduce drag and enhance heat transfer. Variation in the Nusselt number due to shifting of the deepest point of the dimple is presented as well as a detailed analysis of the shear drag and form drag contributions to the overall drag induced by the shifting of the deepest point of dimples downstream. The overall heat transfer efficiency in terms of the volume goodness ratio is also presented to show the variation in heat transfer efficiency as the deepest point is moved.
Prof. Khoo Boo Cheong
Dept. Mech. Eng., National University of Singapore, Singapore.
Email: mpekbc@nus.edu.sg
BC Khoo graduated from the University of Cambridge with a BA (Honours, 1st Class with Distinction). In 1984, he obtained his MEng from the NUS and followed by PhD from MIT in 1989. He joined NUS in 1989. From 1998 to 1999, he was seconded to the Institute of High Performance Computing (IHPC, Singapore) and served as the deputy Director and Director of Research. In 1999, BC returned to NUS and spent time at the SMA-I (Singapore MIT Alliance I) as the co-Chair of High Performance Computation for Engineered Systems Program till 2004. In the period 2005-2013, under the SMA-II, he was appointed as the co-Chair of Computational Engineering Program. In 2011-2012, BC was appointed the Director of Research, Temasek Laboratories, NUS. Since 2012, he has been the Director, Temasek Laboratories. BC Khoo serves on numerous organizing and advisory committees for International Conferences/Symposiums held in USA, China, India, Singapore, Taiwan, Malaysia, Indonesia and others. He is a member of the Steering Committee, HPC (High Performance Computing) Asia. He has received a Defence Technology Team Prize (1998, Singapore) and the prestigious Royal Aeronautical Prize (1980, UK). Among other numerous and academic and professional duties, he is the Associate Editor of Communications in Computational Physics (CiCP) and Advances in Applied Mathematics and Mechanics (AAMM), and is on the Editorial Board of American Journal of Heat and Mass Transfer, Ocean Systems Engineering (IJOSE), International Journal of Intelligent Unmanned Systems (IJIUS), The Open Mechanical Engineering Journal (OME) and The Open Ocean Engineering Journal. In research, BC ‘s interest are in: (1) Fluid-structure interaction; (2) Underwater shock and bubble dynamics; (3) Compressible/Incompressible multi-medium flow. He is the PI of numerous externally funded projects including those from the Defense agencies like ONR/ONR Global and MINDEF (Singapore) to simulate/study the dynamics of underwater explosion bubble(s), flow supercavitation and detonation physics. His work on water circulation and transport across the turbulent air-sea interface has received funding from the then BP International for predicting the effects of accidental chemical spills. Qatar NRF has funded study on internal sloshing coupled to external wave hydrodynamics of (large) LNG carrier. BC has published over 370 international journal papers, and over 370 papers at international conferences/symposiums. He has presented at over 120 plenary/keynote/invited talks at international conferences/symposiums/meetings.
BIO
Dr Henrik Lund is Professor in Energy Planning at Aalborg University and Editor-in-Chief of Elsevier International journal ENERGY. For more than 25 years, his area of expertise has been energy system analysis, energy planning and energy economics. He is the author of more than 200 books and articles and on the Thomson Reuters list of the most highly cited researches in the world.Abstract
This lecture presents the learning of a series of studies that analyze the problems and perspectives of converting the present energy system into a 100 percent renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies including transportation and aviation. The typical smart grid sole focus on the electricity sector often leads to the definition of transmission lines, flexible electricity demands and electricity storage as the primary means to deal with the integration of fluctuating renewable sources. However, the nature of wind power and similar sources has the consequence that these measures are neither very effective nor cost-efficient. The most effective and least-cost solutions are to be found when the electricity sector is combined with the heating sector and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. This presentation illustrates why electricity smart grids should be seen as part of overall smart energy systems and with the case of Denmark illustrate how to design such future energy system.Convective Phase Change Heat and Mass Transfer at Extremes
Convective boiling in confined environment of ultra-small (<10 um) microgaps, with and without pin fins, is a promising approach for dissipating ultra-high heat fluxes in excess of kW/cm2 with and is an area of increased recent attention. Microgaps are thought to be less prone to flow reversals than microchannels because vaporizing coolant can expand in the spanwise as well as downstream direction. I will provide the first principle theoretical framework for coolant selection and design of microgaps for the removal of high heat fluxes via a strategy of high mass flux, high quality, two-phase forced convection. In support of theoretical analysis, I will discuss the results of an experimental investigation of heat transfer performance of three dedicated microgap coolers for hotspot thermal management. In these experiments, a rectangular microgap, batch micromachined in silicon and instrumented with thin-film resistive thermometry, was employed to assess its capability of dissipating extreme heat fluxes of multiple kW/cm2 while keeping the wall temperature within the limits dictated by electronics reliability. Convective boiling in microgap with heights of 5 μm and 10 μm was tested with and without pin fins in the microgap. Microgap pressure drop and wall temperature measurements, mapped into flow regimes, were obtained with R134a as the coolant, for heat fluxes up to 5 kW/cm2, mass fluxes up to 7,000 kg/m2s, at maximum pressures up to 1.5 MPa and outlet vapor qualities approaching unity. These experimental parameters constitute extreme values in terms of microgap height, mass fluxes, and heat fluxes. New flow regimes were observed as a function of increasing heat flux and microgap geometry. Dominant mechanism(s) of two-phase heat transfer responsible for each regime will be postulated based on flow visualization correlated with pressure drop and thermal resistance measurements.
Prof. Andrei G. Fedorov
School of Mechanical Engineering & Petit Institute of Bioengineering & Bioscience
Georgia Institute of Technology, USA
Email: AGF@gatech.edu
Andrei G. Fedorov is the Woodruff Professor in the School of Mechanical Engineering at Georgia Tech. His current research focuses on MEMS-enabled bioanalytical instrumentation, electron-beam-mediated nanomanufacturing, thermal management of high performance electronics, and portable/distributed power generation with CO2 capture. Dr. Fedorov’s research has been recognized by peers, including the 2006 Branimir F. von Turkovich Outstanding Young Manufacturing Engineer Award from the Society of Manufacturing Engineers (SME) “for contributions and accomplishments in the manufacturing industry” and the 2007 Bergles-Rohsenow Award in Heat Transfer from the American Society of Mechanical Engineers (ASME) for “sustained contribution to heat, mass, and radiation transfer.” Most recently, Dr. Fedorov has been selected to become a recipient of the 2010 Gustus L. Larson Memorial Award, given jointly by Pi Tau Sigma (International Mechanical Engineering Honor Society) and the ASME, in recognition of outstanding achievements in mechanical engineering within ten to twenty years following graduation. Dr. Fedorov authored/co-authored over 200 archival articles published in premier technical journals and refereed conference/symposia proceedings, along with numerous invited and keynote presentations at the major national and international conferences. He is a member of International Advisory Board of the Tokyo Tech’s Global Center of Excellence for Energy Science; serves on Editorial Advisory Boards of the International Journal of Multiscale Computational Engineering, International Journal of Interfacial Phenomena and Heat Transfer, the Journal of Nanoelectronics and Optoelectronics, and Transactions of the Japanese Society of Mechanical Engineers (JSME); and consults a number of government agencies and major corporations worldwide. Dr. Fedorov's research has led to development of new technologies for various applications, resulting in over 40 issued and pending patents. For his inventions of biomedical devices, the World Technology Network (WTN), in cooperation with AAAS Science Magazine, CNN and leading technology companies, selected Dr. Fedorov as a WTN Associate and one of the twenty five “most innovative people and organizations in the science and technology world” nominated for the 2005 World Technology Award in Health and Medicine. Dr. Fedorov was an invited participant in the 2006 National Academy of Engineering (NAE) Frontiers of Engineering Symposium, gathering "the nation's top 100 engineers between the ages of 30-45 from academy, industry and national labs." Dr. Fedorov was recognized with the US National Aeronautics and Space Administration (NASA) Invention & Contribution Board Award for development of catalytic reactor technologies, as well as multiple inventor recognition awards from the Semiconductor Research Corporation (SRC) and Microelectronics Advanced Research Corporation (MARCO). With his students he has started several technology companies, in the space of gene/drug delivery microarrays, therapeutic cell manufacturing and thermal management in medicine, to commercialize his inventions. He serves on the Board of Directors of Horizon Theatre Company (http://www.horizontheatre.com/), a leading contemporary theater in Southeast of the United States.
BIO
Dr Henrik Lund is Professor in Energy Planning at Aalborg University and Editor-in-Chief of Elsevier International journal ENERGY. For more than 25 years, his area of expertise has been energy system analysis, energy planning and energy economics. He is the author of more than 200 books and articles and on the Thomson Reuters list of the most highly cited researches in the world.Abstract
This lecture presents the learning of a series of studies that analyze the problems and perspectives of converting the present energy system into a 100 percent renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies including transportation and aviation. The typical smart grid sole focus on the electricity sector often leads to the definition of transmission lines, flexible electricity demands and electricity storage as the primary means to deal with the integration of fluctuating renewable sources. However, the nature of wind power and similar sources has the consequence that these measures are neither very effective nor cost-efficient. The most effective and least-cost solutions are to be found when the electricity sector is combined with the heating sector and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. This presentation illustrates why electricity smart grids should be seen as part of overall smart energy systems and with the case of Denmark illustrate how to design such future energy system.On the Key Issues and Research Progress about the Aerodynamics of Inlet and Exhaust System of Wide Range and High Speed Vehicles
The plenary report will introduce the research work conducted in Nanjing University of Aeronautics and Astronautics (NUAA) about the inlet and exhaust system of wide range, high speed vehicles engine, especially the Supersonic Combustion Ramjet (Scramjet) and Combined Cycle Engine (CCE, such as the Turbine Based Combined Cycle, TBCC). The outline should be as following: 1. The brief introduction of NUAA and the research group; 2. The introduction of culture background of wide range, high speed vehicles engine, especially the Scramjet and CCE; 3. Why the inlet and exhaust system are very important in the Scramjet engine?—A simple comparison between the Scramjet and conventional turbojet engine; 4. The major problems of inlet and exhaust system encountered in the Scramjet and CCE engines; 5. The key issues in the Scramjet inlet and what we did (1) On the design method and performance study of curved compression inlet; (2) On the dynamic flowfield structure and flow control in a typical Scramjet inlet; (3) On the unsteady flow phenomena and control method in a inlet/isolator; (4) On the design and mode transition process of a typical TBCC inlet; 6. The key issues in the Scramjet exhaust system and what we did (1) On the design method and performance study of Single Expansion Ramp Nozzle (SERN) with strong geometric restriction; (2) On the design method and performance study of 3D Single Expansion Ramp Nozzle (SERN) with streamline tracing techniques; (3) On the design and mode transition process of a typical TBCC exhaust system; (4) On the separation pattern and dynamic transition in the over-expanded SERN; (5) On the effect of Fluid-Structure Interaction (FSI) on the TBCC inlet and exhaust system; (6) On the reconstruction of static pressure of compressible flowfield based on the PIV data. 7. Conclusion.
Prof. Jinglei Xu
College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics,China.
Email:xujl@nuaa.edu.cn
In 1996 and 1999, the master's degree and the doctor's degree of fluid machinery and engineering were obtained at Xi’an Jiaotong University, respectively. In 1999, he joined the Nanjing University of Aeronautics and Astronautics and engaged in the teaching and research of the theory and engineering of aerospace propulsion. In 2002, he was employed as an associate professor and was hired as a professor and a doctoral supervisor in 2008. The current director of the Department of Energy and Dynamics and the Head of the Mechanical Head of the Impeller. Professor Xu is mainly engaged in the research of engine internal flow dynamics, hypersonic propulsion system, advanced measurement technology of complex flow field, flow control and pneumatic vector nozzle, etc. More than 90 scientific research papers have been published, including 20 international SCI retrieval periodical papers, nearly 70 EI, ISTP retrieval papers, and more than 20 papers at AIAA, ASME, ISABE and other important international conferences. It has applied for 18 national invention patents and 7 authorizations. In 2012, Prof. Xu won a third prize for national defense science and technology achievement (the first completion person). In 2015, Prof. Xu won the First Prize of National Defense Science and Technology Achievements. In 2019, Prof. Xu won the Second prize for national scientific and technological progress.
Abstract
A tremendous effort has been devoted to improving the energy efficiency of home appliances around the world over the past 2 decades, where the adoption of energy labelling, and the enforcement of Minimum Energy Performance Standards (MEPSs) have led to significant energy savings. These efforts are continuing to bring innovation in refrigerator cabinet (i.e. advanced insulation, improved gaskets), sealed refrigeration system (e.g. low GWP refrigerants, efficient fans, compressors and heat exchangers, adaptive defrosts etc.), user-friendly features (e.g. double doors, internet connectivity, on-line access, internal cameras, music/TV) and legislative improvements enforcing more stringent MEPSs. Increased global competition and improved energy efficiency policies of various governments are responsible for bringing innovation into user friendly product development where more energy efficient products are now appearing in the market. The talk will present an overview of some of the recent advancements including novel/alternative technologies that are responsible for the development of energy efficient household refrigerators.BIO
Dr. Bansal currently works for Viking
Range, Middleby Corporation (USA) as their R&D Lead of Energy Efficiency and
Refrigeration. Previously he worked at Oak Ridge National Laboratory (USA) as
Distinguished R&D Scientist during 2010-15, and the University of Auckland
(New Zealand) as Professor (Personal Chair) of Mechanical Engineering and
Associate Dean Postgraduate of the Faculty of Engineering during 1988-2012. He
has presented numerous plenaries and published over 260 technical papers and
three books. He is a Fellow of ASHRAE and Vice-President of Commission B1 of the
International Institute of Refrigeration. He is currently serving as an
Executive Editor of Applied Thermal Engineering, and Associate Editor of J.
Science and Technology for the Built Environment (previously HVAC&R), and J.
of Process Mechanical Engineering (IMechE, UK).
Abstract
A tremendous effort has been devoted to improving the energy efficiency of home appliances around the world over the past 2 decades, where the adoption of energy labelling, and the enforcement of Minimum Energy Performance Standards (MEPSs) have led to significant energy savings. These efforts are continuing to bring innovation in refrigerator cabinet (i.e. advanced insulation, improved gaskets), sealed refrigeration system (e.g. low GWP refrigerants, efficient fans, compressors and heat exchangers, adaptive defrosts etc.), user-friendly features (e.g. double doors, internet connectivity, on-line access, internal cameras, music/TV) and legislative improvements enforcing more stringent MEPSs. Increased global competition and improved energy efficiency policies of various governments are responsible for bringing innovation into user friendly product development where more energy efficient products are now appearing in the market. The talk will present an overview of some of the recent advancements including novel/alternative technologies that are responsible for the development of energy efficient household refrigerators.BIO
Dr. Bansal currently works for Viking
Range, Middleby Corporation (USA) as their R&D Lead of Energy Efficiency and
Refrigeration. Previously he worked at Oak Ridge National Laboratory (USA) as
Distinguished R&D Scientist during 2010-15, and the University of Auckland
(New Zealand) as Professor (Personal Chair) of Mechanical Engineering and
Associate Dean Postgraduate of the Faculty of Engineering during 1988-2012. He
has presented numerous plenaries and published over 260 technical papers and
three books. He is a Fellow of ASHRAE and Vice-President of Commission B1 of the
International Institute of Refrigeration. He is currently serving as an
Executive Editor of Applied Thermal Engineering, and Associate Editor of J.
Science and Technology for the Built Environment (previously HVAC&R), and J.
of Process Mechanical Engineering (IMechE, UK).