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Large eddy simulation of turbulent heat transfer in a non-isothermal channel : Effects of temperature-dependent viscosity and thermal conductivity

Wang, Lei LU ; Liu, Jian LU ; Hussain, Safeer LU and Sundén, Bengt LU (2019) In International Journal of Thermal Sciences 146.
Abstract

In this work, we perform large eddy simulations (LES) to study the influence of variable viscosity and thermal conductivity on forced convection in a non-isothermal channel flow. To prevent thermal dilatational effect, the gas density is assumed to be constant. The temperature ratio T2/T1 is varied from 1.01 to 2.2, where T2 and T1 are the temperatures of hot and cold walls, respectively. The mean turbulent Reynolds number is kept the same at 395. The results indicated that the mean flow fields are significantly affected by the temperature-dependent fluid properties. Despite the modified velocity and temperature profiles, it is interesting to note that the molecular momentum and heat transport... (More)

In this work, we perform large eddy simulations (LES) to study the influence of variable viscosity and thermal conductivity on forced convection in a non-isothermal channel flow. To prevent thermal dilatational effect, the gas density is assumed to be constant. The temperature ratio T2/T1 is varied from 1.01 to 2.2, where T2 and T1 are the temperatures of hot and cold walls, respectively. The mean turbulent Reynolds number is kept the same at 395. The results indicated that the mean flow fields are significantly affected by the temperature-dependent fluid properties. Despite the modified velocity and temperature profiles, it is interesting to note that the molecular momentum and heat transport across the channel remain unchanged. Meanwhile, pronounced differences are exhibited for various turbulence statistics such as root-mean-square velocity and temperature fluctuations, Reynolds shear stress, and correlation between streamwise velocity and temperature. Compared with the isothermal flows, it is also found that the presence of the temperature gradient tends to diminish heat transfer. With increasing the temperature ratio, the Nusselt numbers for both sides are reduced. Moreover, the hot side has a higher Nusselt number than the one at the cold side.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Constant gas density, Large eddy simulation, Temperature gradient, Turbulent forced convection, Variable physical properties
in
International Journal of Thermal Sciences
volume
146
article number
106094
publisher
Elsevier
external identifiers
  • scopus:85072021993
ISSN
1290-0729
DOI
10.1016/j.ijthermalsci.2019.106094
language
English
LU publication?
yes
id
9c669e99-1d74-473c-9e71-79e655af2a93
date added to LUP
2019-09-16 09:04:23
date last changed
2019-11-25 09:34:20
@article{9c669e99-1d74-473c-9e71-79e655af2a93,
  abstract     = {<p>In this work, we perform large eddy simulations (LES) to study the influence of variable viscosity and thermal conductivity on forced convection in a non-isothermal channel flow. To prevent thermal dilatational effect, the gas density is assumed to be constant. The temperature ratio T<sub>2</sub>/T<sub>1</sub> is varied from 1.01 to 2.2, where T<sub>2</sub> and T<sub>1</sub> are the temperatures of hot and cold walls, respectively. The mean turbulent Reynolds number is kept the same at 395. The results indicated that the mean flow fields are significantly affected by the temperature-dependent fluid properties. Despite the modified velocity and temperature profiles, it is interesting to note that the molecular momentum and heat transport across the channel remain unchanged. Meanwhile, pronounced differences are exhibited for various turbulence statistics such as root-mean-square velocity and temperature fluctuations, Reynolds shear stress, and correlation between streamwise velocity and temperature. Compared with the isothermal flows, it is also found that the presence of the temperature gradient tends to diminish heat transfer. With increasing the temperature ratio, the Nusselt numbers for both sides are reduced. Moreover, the hot side has a higher Nusselt number than the one at the cold side.</p>},
  author       = {Wang, Lei and Liu, Jian and Hussain, Safeer and Sundén, Bengt},
  issn         = {1290-0729},
  language     = {eng},
  publisher    = {Elsevier},
  series       = {International Journal of Thermal Sciences},
  title        = {Large eddy simulation of turbulent heat transfer in a non-isothermal channel : Effects of temperature-dependent viscosity and thermal conductivity},
  url          = {http://dx.doi.org/10.1016/j.ijthermalsci.2019.106094},
  doi          = {10.1016/j.ijthermalsci.2019.106094},
  volume       = {146},
  year         = {2019},
}