Correction to "New Measurements of the Apparent Thermal Conductivity of Nanofluids and Investigation of Their Heat Transfer Capabilities"

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Commonly asked questions in thermodynamics / Marc J. Assael ... [et al.].

Includes bibliographical references and index.Book fair2012xxi, 346 p. :"Accurate and clearly explained answers to common questions. Every scientist and engineer encounters problems that may be solved at least in part using the principles of thermodynamics. The importance of thermodynamics is often so fundamental to life that we should all have a fairly detailed understanding of this core field. This clearly written, easy-to-follow guide allows even nonscientists considering use of alternative fuel sources to achieve a solid grounding in thermodynamics. The authors cover topics spanning from energy sources to the environment to climate change. A broad audience of general readers, students, industry professionals, and academic researchers will appreciate the answers found in this book"--"Acutely aware that this is especially the case for thermodynamics and thermophysics. The subjects of thermodynamics and thermophysics play a role to some extent in every other discipline of science from the nano-scale to the cosmos and astrophysics with biology and life-sciences on the way. Furthermore, while some aspects of thermodynamics under pin the very fundamentals of these subjects, others parts of thermodynamics impact upon almost every application in engineering. In consequence the range of individuals who may have questions about thermodynamics and its applications encompass most of the world's scientists and engineers at most of the levels of activity from the undergraduate to the research frontier. "-

Commonly Asked Questions in Thermodynamics

Have you ever had a question that keeps persisting and for which you cannot find a clear answer? Is the question seemingly so "simple" that the problem is glossed over in most resources, or skipped entirely? CRC Press/Taylor and Francis is pleased to introduce Commonly Asked Questions in Thermodynamics, the first in a new series of books that address the questions that frequently arise in today's major scientific and technical disciplines. Designed for a wide audience, from students and researchers to practicing professionals in related areas, the books are organized in a user frien

DOI:10.1068/htwu197 Measurement of the viscosity of cyclopentane

Abstract. Measurements for the viscosity of cyclopentane in the liquid phase are presented. The measurements cover the temperature range from 210 to 310 K, from atmospheric pressure up to 25 MPa, and were performed in a vibrating-wire viscometer. The uncertainty of the measurements is estimated to be 0.5%, rising to 1 % at low temperatures, an estimate confirmed by the comparison of the viscosity of water and toluene with standard correlations.

Towards the viscosity of refrigerant/oil mixtures

The paper describes the current status of knowledge of the viscosity of refrigerants R32, R124, R125, R134a, R141b and R152a and their mixtures, in the liquid and vapour states along the saturation line and as a function of pressure. The analysis reveals that there remain significant discrepancies between the results of measurements of the viscosity of pure refrigerants by different authors. These differences are particularly marked when different techniques are employed but almost always exceed the claimed mutual uncertainties. The theoretically-based scheme of Vesovic and Wakeham (VW) for the prediction of the viscosity of mixtures from their pure components is used in a modified form to examine predictions of the behaviour of refrigerant mixtures

Qualitative and Quantitative Investigation of Multiple Large Eddy Simulation Aspects for Pollutant Dispersion in Street Canyons Using OpenFOAM

Air pollution is probably the single largest environment risk to health and urban streets are the localized, relevant hotspots. Numerous studies reviewed the state-of-the-art models, proposed best-practice guidelines and explored, using various software, how different approaches (e.g., Reynolds-averaged Navier–Stokes (RANS), large eddy simulations (LES)) inter-compare. Open source tools are continuously attracting interest but lack of similar, extensive and comprehensive investigations. At the same time, their configuration varies significantly among the related studies leading to non-reproducible results. Therefore, the typical quasi-2D street canyon geometry was selected to employ the well-known open-source software OpenFOAM and to investigate and validate the main parameters affecting LES transient simulation of a pollutant dispersion. In brief, domain height slightly affected street level concentration but source height had a major impact. All sub-grid scale models predicted the velocity profiles adequately, but the k-equation SGS model best-resolved pollutant dispersion. Finally, an easily reproducible LES configuration is proposed that provided a satisfactory compromise between computational demands and accuracy

Implicit Definition of Flow Patterns in Street Canyons—Recirculation Zone—Using Exploratory Quantitative and Qualitative Methods

Air pollution is a major health hazard for the population that increasingly lives in cities. Street-scale Air Quality Models (AQMs) are a cheap and efficient way to study air pollution and possibly provide solutions. Having to include all the complex phenomena of wind flow between buildings, AQMs employ several parameterisations, one of which is the recirculation zone. Goal of this study is to derive an implicit or explicit definition for the recirculation zone from the flow in street canyons using computational fluid dynamics (CFD). Therefore, a CFD-Large Eddy Simulation model was employed to investigate street canyons with height to width ratio from 1 to 0.20 under perpendicular wind direction. The developed dataset was analyzed with traditional methods (vortex visualization criteria and pollutant dispersion fields), as well as clustering methods (machine learning). Combining the above analyses, it was possible to extract qualitative features that agree well with literature but most importantly to develop quantitative expressions that describe their topology. The extracted features’ topology depends strongly on the street canyon dimensions and not surprisingly is independent of the wind velocity. The developed expressions describe areas with common flow characteristics inside the canyon and thus they can be characterised as an implicit definition for the recirculation zone. Furthermore, the presented methodology can be further applied to cover more parameters such us oblique wind direction and heated-facades and more methods for data analysis

Measurements of the Thermal Conductivity of 1,1,1,3,3-Pentafluoropropane (R245fa) and Correlations for the Viscosity and Thermal Conductivity Surfaces

New experimental data on the thermal conductivity of 1,1,1,3,3-pentafluoropropane (R245fa) are reported that cover a wide range of liquid conditions. These new experimental data were made with a transient hot-wire apparatus and cover the liquid phase over a temperature range of 173–344 K and a pressure range of 0.1–71 MPa. The experimental data reported here have an expanded uncertainty (0.95 level of confidence) of less than 1%. The measurements are used with selected literature data to develop correlations for the thermal conductivity. On the basis of this expanded uncertainty and comparisons with experimental data, the thermal conductivity correlation for R245fa is estimated to have a relative expanded uncertainty (0.95 level of confidence) of about 2% at a 95% confidence level for the liquid phase at pressures to 70 MPa and 2% for the vapor phase. In addition, we surveyed literature data and developed a correlation for the viscosity of R245fa. The estimated relative expanded uncertainty (0.95 level of confidence) of this correlation is 3% for the liquid phase at pressures to 40 MPa and 2% for the vapor phase