Further Remarks on the Stability of Boiling Heat Transfer
Author: N. Zuber
Publisher:
Published: 1958
Total Pages: 80
ISBN-13:
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Author: N. Zuber
Publisher:
Published: 1958
Total Pages: 80
ISBN-13:
DOWNLOAD EBOOKAuthor:
Publisher:
Published: 1958
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAn analytical expression is presented which permits the prediction of the maximum nucleate heat flux in pool boiling of saturated or subcooled liquids. The numerical values of the empirical constants which appear in the Kutateladze and Borishanskii criteria for the burnout'' heat flux are derived from the theory. An analytical expression for the empirical function which appears in the correlation of Griffith is also derived. The hitherto unexplored features of transition boiling, i.e., the hydrodynamic instability, the well defined geometrical configuration and the frequency dependence are described, supported by experimental evidence, and used as the basis for the analytical work. The peak heat flux in transition boiling is shown to be limited by the combined effects of Taylor and Helmholtz instabilitiess whereas the minimum transitional heat flux is limited by the effect of Taylor instability ony. The analysis leads to the conclusion that because of the statistical nature of the ddsturbances and the bandwidth'' of the unstable wavelengths which govern the process, an inherent uncertainty exists in determining the exact value of the heat flux at burnout.'' The width of this uncertainty range is plus or minus 14%. The often noted poor reproducibility of experimental data on burnout'' can be inferred, therefore, from the analysis. The reason analytical attacks upon the burnout'' problem, based upon considerations of bubble agitation and other nucleate boiling characteristics, have not been successful is discussed. The literature has shown conclusively that the surface conddtions play the dominant role in determining the superheat accompanying a given heat flux. The analysis reveals, in addition, that even if the nucleating characteristics of the surface were known the problem could still not be solved from these considerations because the mechanism of the instability occurs in the fluid away from the surface. The extension of the analysis to flow systems is briefly discussed. (auth).
Author: N. Zuber
Publisher:
Published: 1959
Total Pages: 216
ISBN-13:
DOWNLOAD EBOOKAuthor: Brookhaven National Laboratory
Publisher:
Published: 1948
Total Pages:
ISBN-13:
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Publisher: Academic Press
Published: 1968
Total Pages: 551
ISBN-13: 0080575595
DOWNLOAD EBOOKAdvances in Heat Transfer
Author: George Yadigaroglu
Publisher: Springer
Published: 2017-08-19
Total Pages: 221
ISBN-13: 3319587188
DOWNLOAD EBOOKThis book is the maiden volume in a new series devoted to lectures delivered through the annual seminars “Short Courses on Multiphase Flow,” held primarily at ETH Zurich continuously since 1984. The Zurich short courses, presented by prominent specialists in the various topics covered, have attracted a very large number of participants. This series presents fully updated and when necessary re-grouped lectures in a number of topical volumes. The collection aims at giving a condensed, critical and up-to-date view of basic knowledge on multiphase flows in relation to systems and phenomena encountered in industrial applications. The present volume covers the background of Multiphase Flows (MPF) that introduces the reader to the particular nature and complexity of multiphase flows and to basic but critical aspects of MPFs including concepts and the definition of the quantities of interest, an introduction to modelling strategies for MPFs, flow regimes, flow regime maps and tr ansition criteria. It also deals with the ubiquitous needs of the multiphase-flow modeller, namely pressure drop and phase distribution, i.e., the void fraction and the topology of the phases that determines the flow regimes.
Author: Jack Ekin
Publisher: Oxford University Press
Published: 2006-10-12
Total Pages: 704
ISBN-13: 0198570546
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Author: George D. Huffman
Publisher:
Published: 1963
Total Pages: 112
ISBN-13:
DOWNLOAD EBOOKAn assessment of working fluids for use in a high-temperature dynamic power conversion system is presented. The method of comparison of the various fluids consists of a preliminary design of the major system components. The results are presented as conversion system weights for the considered fluids, potassium, sodium, lithium, bismuth, and lead, at various values of turbine inlet temperatures. On the basis of the generated data, it has been concluded that only potassium and sodium are practical for use as a working fluid in the temperature range of consideration, 2000 to 4000 R. It is further concluded that potassium and sodium at turbine inlet temperatures from 2800 to 3200 R offer systems of sufficiently low weight to warrant further and more detailed investigations.