This Brief reports on heat transfer from a solid boundary in a saturated porous medium. Experiments reveal overall heat transfer laws when the flow along the wall is driven by buoyancy produced by large temperature differences, and mathematical analysis using advanced volume-averaging techniques produce estimates of how heat is dispersed in the porous zone. Engineers, hydrologists and geophysicists will find the results valuable for validation of laboratory and field tests, as well as testing their models of dispersion of heat and mass in saturated media.

This updated edition of a widely admired text provides a user-friendly introduction to the field that requires only routine mathematics. The book starts with the elements of fluid mechanics and heat transfer, and covers a wide range of applications from fibrous insulation and catalytic reactors to geological strata, nuclear waste disposal, geothermal reservoirs, and the storage of heat-generating materials. As the standard reference in the field, this book will be essential to researchers and practicing engineers, while remaining an accessible introduction for graduate students and others entering the field. The new edition features 2700 new references covering a number of rapidly expanding fields, including the heat transfer properties of nanofluids and applications involving local thermal non-equilibrium and microfluidic effects.

To improve the confidence of subsurface storage of fluids such as carbon-dioxide, acid-gas and hydrogen at various geological sites, a proper fluid dynamic understanding of flow phenomena occurring because of injecting these source fluids into a porous medium is necessary. While many advancements have been made in predicting the fluid flows in a uniform porous medium, the flow dynamics inside a non-uniform porous media remains less well understood. In this Thesis, we use theory, numerical simulations and experiments to clarify the fluid mechanics of injecting a source fluid into a saturated, multi-layered porous media in which each of the adjacent layers are separated by a sharp permeability jump. Throughout this study, we have considered small density differences between the source and ambient fluids (satisfying the Boussinesq approximation) and both these fluids are completely miscible with each other. The goal of the study is to inform three practical questions. The first research component is to predict the early-time spreading dynamics of plume fluid striking an inclined permeability jump, within porous media having upper- and lower-layers of comparable thicknesses. The plume fluid, upon striking a permeability jump, results in a pair of oppositely directed gravity currents propagating along slope in the up- and downdip directions. To address the flow dynamics along an inclined permeable boundary, we develop a theoretical model in which we derive coupled non-linear partial differential equations describing gravity currents propagating along slope and their draining into the lower layer. The model predicts flow dynamics at both transient- and steady-state conditions. We further validate this model with similitude laboratory experiments. Experimental images show that the interface of the flow front is blurred due to hydrodynamics dispersion, and hence is not especially sharp. The implications of this observation vis-{\` a}-vis theoretical model assumptions are discussed. The second research component is to study the effect of impermeable bottom and sidewall boundaries on the dynamics of the injected fluid. For this, we construct a two-layered porous medium inside a rectangular box and conduct experiments for various combinations of the source condition, permeability jump angle and layer depth. The experiments reveal the formation of two pairs of gravity currents, one in the upper layer (propagating along the permeability jump), and the second in the lower layer (propagating along the bottom boundary of the box). The dynamical influence of one gravity current upon the other, such as the occurrence of runout-override and remobilization from a state of runout, is investigated. At later instants in time, the gravity current flows are impeded due to the vertical sidewall boundaries which allows us to distinguish between two qualitatively different filling regimes, i.e.\,sequential vs.~simultaneous filling of the upper- and lower-layers. Furthermore, parameter combinations conducive to one or the other filling regime are also identified. The third research component regards to the flow pattern inside a more complicated multi-layered porous medium, i.e.~consisting of up to five layers. For this we derive steady analytical solutions for the gravity currents formed along each of the permeability jump boundaries. The model predicts the outer envelope of the flow pattern corresponding to steady flow conditions. Finite-element based COMSOL simulations are also performed for different combinations of layer permeabilities and also by changing the permeability jump angles. The comparison of outer envelope with the theory shows good agreement. Also, the impact of adding intermediate layers of different permeabilities on the maximum span of runout and storage areas are investigated.

This book comprises the select proceedings of the International Conference on Recent Trends in Developments of Thermofluids and Renewable Energy (TFRE 2020). The major topics covered include aerodynamics, alternate energy, bio fuel, bio heat transfer, computational fluid dynamics, control mechanism for constant power generation, and energy storage. The book also discusses latest developments in the fields of electric vehicles, hybrid power systems, and solar and renewable energy. Given the scope of its contents, this book will be useful for students, researchers, and professionals interested in the field of thermofluids and renewable energy resources.

CLIFFORD K. HOAND STEPHEN W. WEBB Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185, USA Gas and vapor transport in porous media occur in a number of important applications includingdryingofindustrialandfoodproducts,oilandgasexploration,environm- tal remediation of contaminated sites, and carbon sequestration. Understanding the fundamental mechanisms and processes of gas and vapor transport in porous media allows models to be used to evaluate and optimize the performance and design of these systems. In this book, gas and vapor are distinguished by their available states at stan- ? dard temperature and pressure (20 C, 101 kPa). If the gas-phase constituent can also exist as a liquid phase at standard temperature and pressure (e. g. , water, ethanol, toluene, trichlorothylene), it is considered a vapor. If the gas-phase constituent is non-condensable at standard temperature and pressure (e. g. , oxygen, carbon di- ide, helium, hydrogen, propane), it is considered a gas. The distinction is important because different processes affect the transport and behavior of gases and vapors in porous media. For example, mechanisms specific to vapors include vapor-pressure lowering and enhanced vapor diffusion, which are caused by the presence of a g- phase constituent interacting with its liquid phase in an unsaturated porous media. In addition, the “heat-pipe” exploits isothermal latent heat exchange during evaporation and condensation to effectively transfer heat in designed and natural systems.