scholarly journals Bulk transfer coefficients of momentum and sensible heat over semiarid grassland surface and their parameterization scheme

2013 ◽  
Vol 62 (9) ◽  
pp. 099202
Author(s):  
Yue Ping ◽  
Zhang Qiang ◽  
Li Yao-Hui ◽  
Wang Run-Yuan ◽  
Wang Sheng ◽  
...  
Keyword(s):  
Parameterization Scheme ◽  
Sensible Heat ◽  
Transfer Coefficients ◽  
Semiarid Grassland ◽  
Bulk Transfer Coefficients

Diffusion Layer Theory for Turbulent Vapor Condensation With Noncondensable Gases

1993 ◽  
Vol 115 (4) ◽  
pp. 998-1003 ◽  
Author(s):  
P. F. Peterson ◽  
V. E. Schrock ◽  
T. Kageyama
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Mass Transfer ◽  
Vapor Condensation ◽  
Sensible Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Noncondensable Gas ◽  
Noncondensable Gases ◽  
Vertical Tubes

In turbulent condensation with noncondensable gas, a thin noncondensable layer accumulates and generates a diffusional resistance to condensation and sensible heat transfer. By expressing the driving potential for mass transfer as a difference in saturation temperatures and using appropriate thermodynamic relationships, here an effective “condensation” thermal conductivity is derived. With this formulation, experimental results for vertical tubes and plates demonstrate that condensation obeys the heat and mass transfer analogy, when condensation and sensible heat transfer are considered simultaneously. The sum of the condensation and sensible heat transfer coefficients becomes infinite at small gas concentrations, and approaches the sensible heat transfer coefficient at large concentrations. The “condensation” thermal conductivity is easily applied to engineering analysis, and the theory further demonstrates that condensation on large vertical surfaces is independent of the surface height.

Transfer coefficients of sensible heat on a snowmelt surface

1994 ◽  
Vol 53 (3-4) ◽  
pp. 233-240 ◽  
Author(s):  
N. Ishikawa ◽  
Y. Kodama
Keyword(s):  
Sensible Heat ◽  
Transfer Coefficients

scholarly journals Characteristics of Land–Atmosphere Interaction Parameters over the Tibetan Plateau

2011 ◽  
Vol 12 (4) ◽  
pp. 702-708 ◽  
Author(s):  
Shuzhou Wang ◽  
Yaoming Ma
Keyword(s):  
Heat Transfer ◽  
Tibetan Plateau ◽  
Transfer Coefficient ◽  
Momentum Transfer ◽  
Roughness Length ◽  
The Tibetan Plateau ◽  
Transfer Coefficients ◽  
Bulk Transfer Coefficients ◽  
Resistance To Heat ◽  
Excess Resistance

Abstract In this study, eddy covariance flux data collected from three research stations on the Tibetan Plateau—Qomolangma for Atmospheric and Environmental Observation and Research, Nam Co for Multisphere Observation and Research, and Southeast Tibet Station for Alpine Environment Observation and Research, Chinese Academy of Sciences—are used to analyze the variation of momentum transfer coefficient (CD), heat transfer coefficient (CH), aerodynamic roughness length (z0m), thermal roughness length (z0h), and excess resistance to heat transfer (kB−1, where k is von Kármán’s constant and B−1 is a non-dimensional bulk parameter). The following results are found. The monthly average surface roughness, bulk transfer coefficient, and excess resistance to heat transfer at all three stations are obtained. The values of average heat bulk transfer coefficients are larger than those of average momentum bulk transfer coefficients at all three stations. The parameter kB−1 exhibits clear diurnal variations with lower values in the night and higher values in the daytime, especially in the afternoon. Negative values of kB−1 are often observed in the night for relatively smooth surfaces on the Tibetan Plateau, indicating that heat transfer efficiency may exceed that of momentum transfer.

Latent and Sensible Heat-Transfer Rates in the Boiling of Binary Mixtures

1982 ◽  
Vol 104 (3) ◽  
pp. 474-478 ◽  
Author(s):  
J. R. Thome
Keyword(s):  
Heat Transfer ◽  
Heat Transport ◽  
Binary Mixtures ◽  
Boiling Heat Transfer ◽  
Constant Heat Flux ◽  
Absolute Pressure ◽  
Sensible Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Boiling Heat Transfer Coefficient

Nucleate pool boiling bubble departure data were obtained for the liquid nitrogen-argon cryogenic binary mixture system at 1.3 atmospheres absolute pressure. The latent and sensible heat transport rates at individual boiling sites were calculated from the data to deduce their effect on the degradation in the boiling heat-transfer coefficient in binary mixtures. The latent heat-transfer rate is a result of the bubble evaporation mechanism and the sensible heat-transport rate is due to cyclic thermal boundary layer stripping by departing bubbles. The latent and sensible heat-transport rates at individual boiling sites were found to decrease to a minimum at the maximum vapor-liquid mole fraction difference for both constant heat flux and wall superheating conditions. The large decrease in binary boiling heat-transfer coefficients was thus partially explained by the retardation of these two mechanisms and should be included in any model for predicting boiling heat-transfer coefficients in binary and multicomponent mixtures.

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