Massachusetts Institute of Technology
|Evelyn N. Wang is an Associate Professor, the Gail E. Kendall Professor, in the Mechanical Engineering Department at MIT. She is also the Associate Director of the Solid State Solar Thermal Energy Conversion (S3TEC) Center, a DOE Energy Frontiers Research Center. She received her BS from MIT in 2000 and MS and PhD from Stanford University in 2001, and 2006, respectively. From 2006-2007, she was a postdoctoral researcher at Bell Laboratories, Alcatel-Lucent. Her research interests include fundamental studies of micro/nanoscale heat and mass transport and the development of efficient thermal management, water desalination, and solar thermal energy systems. Her work has been honored with awards including the 2012 ASME Bergles-Rohsenow Young Investigator Award in Heat Transfer, as well as several best paper awards at various conferences.|
University of Sydney
|Professor Steve Armfield investigates the fluid mechanics of a range of environmental and industrial flows using computational, theoretical and experimental approaches, leading to applications as diverse as improved river management and the design of more efficient building ventilation systems. My main focus is on the development of computational models and algorithms to allow the prediction of highly unsteady, buoyancy-driven and -dominated flows, such as the natural convection boundary layers that develop adjacent to vertical heated surfaces, the two-layer mixing flow that occurs when a lighter fluid passes over a denser fluid, and thermal fountains and plumes.|
Queensland University of Technology
|Ian Turner is a professor of computational mathematics in the School of Mathematical Sciences at the Queensland University of Technology. His main research interests are in the ﬁelds of computational mathematics and numerical analysis, where he has over thirty years experience in solving systems of coupled, nonlinear partial diﬀerential equations that govern ﬂow in porous media. He has published over 200 research articles in a wide cross section of journals spanning science and engineering, and his multidisciplinary research demonstrates a strong interaction with industry. He was named in the 2015 Thomson Reuters list of Highly Cited Researchers.|
Evelyn N. Wang (Massachusetts Institute of Technology)
Nanoengineered surfaces offer new possibilities to manipulate fluidic and thermal transport processes for a variety of applications including thermal management and energy conversion systems. In this talk, I will first discuss the use of nanoengineered surfaces to increase efficiency in solar thermophotovoltaic devices. Such surfaces allow us to engineer the spectral properties and to define the active area of the emitter with respect to the absorber. Accordingly, we report efficiencies up to 6 times greater than those previously reported. I will also discuss opportunities to use nanoengineered surfaces to enhance phase-change heat transfer. Specifically in condensation, we demonstrated enhanced performance by using scalable superhydrophobic nanostructures via jumping-droplets. Furthermore, we observed that these jumping-droplets carry a residual charge, which can be harnessed for electrostatic energy harvesting. These studies provide important insights into the complex physical processes underlying heat-structure interactions and offer a path to achieving increased efficiency in next generation energy systems.
S. W. Armfield (University of Sydney), W. Lin (James Cook University), N. Williamson (University of Sydney)
Fountains occur when dense fluid is injected upwards (or light fluid downwards) into a less (more) dense environment. In the absence of boundary effects (i.e. a free fountain) the denser fluid penetrates to a ﬁnite height, stops, and falls back around the rising fluid as an annular plunging plume. The initial maximum rise height of the negatively buoyant jet is determined by a balance between the source momentum flux and the opposing source buoyancy flux, and by the amount of ambient fluid entrained by the jet. The ﬁnal fountain height is also determined by the interaction between the rising inner fluid and the falling outer fluid. Therefore our ability to predict the fountain height, and other quantities such as the density of the fountain efflux fluid, depends critically on our ability to predict the entrainment and the interaction and mixing of the rising and falling flows, which in turn requires a thorough understanding of the dynamics and structure of the flows. As well as their wide range of applications fountains are a canonical turbulent flow containing features of jets and plumes, with strong mixing and entrainment, all mediated by the momentum/buoyancy balance.
Many of the fountain features show a strong degree of self-similarity and there has been considerable success in developing scaling and integral relations that accurately predict the relation between quantities such as the fountain height and the control parameters for the flow. Many typical fountain applications, such as in building ventilation and effluent discharge, occur at relatively low turbulent Reynolds numbers, also making the flow accessible via Direct and Large Eddy Simulation. Existing scaling and integral relations will be reviewed and discussed with respect to recent numerical simulations.
Ian Turner (Queensland University of Technology)
Multiscale approaches for simulating transport in porous media generally fall into four main categories: (i) upscaling techniques such as homogenisation, where calculations on a representative ‘mirocell’ are used to derive the effective coefficients in the macroscopic averaged equations; (ii) multiscale finite difference, volume and element techniques, where an approximate fine-scale solution is reconstructed based on a two-level coarse grid solution; (iii) multiscale continuum-network models that couple a network model on the microscale with a continuum model on the macroscale; and (iv) distributed microstructure models, which consist of coupled continuum equations that have to be solved simultaneously at the macroscopic and microscopic (microcell) scales. Here we focus on models based on the approaches (i) and (iv) for furthering the understanding of the drying process.
An overview of the important role that ﬁnite volume methods and Krylov subspace approaches play in the computational modelling of flow in heterogeneous, porous media will be presented. The solution strategies employed for the nonlinear macroscopic conservation laws are presented, together with the novel computational techniques used for simulating the transport phenomena evident at the microscale. Some recent industrial applications related to wood drying are chosen to elucidate the effectiveness of this modelling framework and to assess the computational performance of the underlying algorithms.