Heat transfer

About: Heat transfer is a research topic. Over the lifetime, 181795 publications have been published within this topic receiving 2923586 citations. The topic is also known as: heat exchange.

Inside the Supernova: A Powerful Convective Engine

Abstract: Condensed Abstract: We present an extensive study of the inception of supernova explosions by following the evolution of the cores of two massive stars (15 Msun and 25 Msun) in two dimensions. Our calculations begin at the onset of core collapse and stop several 100 ms after the bounce, at which time successful explosions of the appropriate magnitude have been obtained. (...) Guided by our numerical results, we have developed a paradigm for the supernova explosion mechanism. We view a supernova as an open cycle thermodynamic engine in which a reservoir of low-entropy matter (the envelope) is thermally coupled and physically connected to a hot bath (the protoneutron star) by a neutrino flux, and by hydrodynamic instabilities. (...) In essence, a Carnot cycle is established in which convection allows out-of-equilibrium heat transfer mediated by neutrinos to drive low entropy matter to higher entropy and therefore extracts mechanical energy from the heat generated by gravitational collapse. We argue that supernova explosions are nearly guaranteed and self-regulated by the high efficiency of the thermodynamic engine. (...) Convection continues to accumulate energy exterior to the neutron star until a successful explosion has occurred. At this time, the envelope is expelled and therefore uncoupled from the heat source (the neutron star) and the energy input ceases. This paradigm does not invoke new or modified physics over previous treatments, but relies on compellingly straightforward thermodynamic arguments. It provides a robust and self-regulated explosion mechanism to power supernovae which is effective under a wide range of physical parameters.

Process heat transfer

Abstract: Process Heat Transfer presents comprehensive coverage of both classical and new topics on the subject. Classical aspects discussed include shell-and-tube heat exchangers, double pipe exchangers, reboilers, and condensers. New topics covered include process integration, heat exchanger selection, heat transfer associated with thermodynamic cycles, and ohmic heating. The book includes both worked examples and problems at the end of each chapter. Extensive sections on the fundamental principles of heat transfer and fluid flow, in addition to a wealth of material on applied techniques and problems, make Process Heat Transfer an invaluable text/reference for students and professionals in mechanical engineering, chemical engineering, and applied heat transfer. "In summary, the essential usefulness of this book is as a 'one-stop' source of information on the basic theory and mechanism of heat transfer, typical correlations and methods for use in thermal design, and all types of modern process heat transfer equipment...the book represents very good value and can certainly be recommended as a textbook for general courses on process heat transfer...it will also be very useful as a general source book for the practicing engineer who needs access to a wide range of information on process heat transfer in a single volume...." - From a review in Heat Transfer Engineering 1042 pages, © 1994

Natural convection cooling of a localised heat source at the bottom of a nanofluid-filled enclosure

Abstract: This article presents a numerical study of natural convection cooling of a heat source embedded on the bottom wall of an enclosure filled with nanofluids. The top and vertical walls of the enclosure are maintained at a relatively low temperature. The transport equations for a Newtonian fluid are solved numerically with a finite volume approach using the SIMPLE algorithm. The influence of pertinent parameters such as Rayleigh number, location and geometry of the heat source, the type of nanofluid and solid volume fraction of nanoparticles on the cooling performance is studied. The results indicate that adding nanoparticles into pure water improves its cooling performance especially at low Rayleigh numbers. The type of nanoparticles and the length and location of the heat source proved to significantly affect the heat source maximum temperature.