Format:
7
ISSN:
1879-2189
Content:
The shape of the mean temperature profile in turbulent Rayleigh–Bénard Convection (RBC) plays an important role in the understanding and prediction of heat transfer. Based on the characteristics of the mean temperature profile, we propose a four-layer structure for each half of a turbulent RBC cell. Layer I, a thin layer adjacent to the bottom or top plate, is the traditional thermal diffusional sub-layer, in which the mean temperature is dominated by linear growth. It is found, empirically, that there exists a layer in which the mean temperature deficit can be approximated by a power-law decay, and this layer is called Layer III. Between Layer I and Layer III there exists a transitional or buffer layer, which is designated Layer II. Outside Layer III is a well-mixed outer layer, Layer IV. In a fully turbulent RBC, Layers I, II, and III occupy a small fraction of the RBC cell, but these layers contain nearly all the temperature increment. Layer IV occupies a large fraction of the RBC cell, but with negligible temperature increment. One parameter that quantifies the shape of the mean temperature is the thermal displacement thickness [delta theta]d. The four-layer model is used to clarify the contribution of different layers to the thermal displacement thickness in a turbulent RBC. It is found that the integral in the calculation of the thermal displacement thickness mainly comes from Layer III.
In:
International journal of heat and mass transfer, Amsterdam [u.a.] : Elsevier, 1960, 148(2020) vom: Feb., Artikel-ID 119021, 1879-2189
In:
volume:148
In:
year:2020
In:
month:02
In:
elocationid:119021
In:
extent:7
Language:
English
DOI:
10.1016/j.ijheatmasstransfer.2019.119021
URL:
https://doi.org/10.1016/j.ijheatmasstransfer.2019.119021
Author information:
Du Puits, Ronald 1964-
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