Heat transfer deterioration in upward and downward pipe flows of supercritical n-decane for actively regenerative cooling
Li, Yong LU
; Markides, Christos N.
; Sunden, Bengt
LU
and Xie, Gongnan
LU
(2021)
In International Journal of Thermal Sciences
168.
- Abstract
In this paper, we consider the flow and heat transfer behaviour of turbulent upward and downward flows of supercritical n-decane, in order to reveal the features of heat transfer deterioration (HTD) that would be expected in relevant active regenerative cooling systems for scramjet engines. Specific focus is placed on key velocity-field features that appear in these flows. Following the validation of six turbulence models, the SST k-ω and RNG k-ϵ models are found to be suitable for simulating the upward and downward flow cases, respectively. “M” type velocity profiles (a non-monotonicity of the velocity along the radial direction) are observed, which arise due to a spatially-varying interplay between the inertial and viscous forces in... (More)
In this paper, we consider the flow and heat transfer behaviour of turbulent upward and downward flows of supercritical n-decane, in order to reveal the features of heat transfer deterioration (HTD) that would be expected in relevant active regenerative cooling systems for scramjet engines. Specific focus is placed on key velocity-field features that appear in these flows. Following the validation of six turbulence models, the SST k-ω and RNG k-ϵ models are found to be suitable for simulating the upward and downward flow cases, respectively. “M” type velocity profiles (a non-monotonicity of the velocity along the radial direction) are observed, which arise due to a spatially-varying interplay between the inertial and viscous forces in the flow domain, while larger velocity gradients in the buffer layer are also observed that contribute to the phenomenon of HTD. Furthermore, it is found that the secondary flows as well as the different mass fluxes that arise due to the velocity increase from the wall to the flow core zone (i.e., the influencing range and intensity of cross-sectional kinetic energy), respectively, are observed in the HTD development region, as well as the HTD peak area and degradation regions. A zone of higher thermal diffusion appears in the near-wall region, which acts as a thermal barrier and contributes to HTD.
(Less)
- author
- Li, Yong
LU
; Markides, Christos N.
; Sunden, Bengt
LU
and Xie, Gongnan
LU
- organization
- publishing date
- 2021-10-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Heat transfer deterioration, Secondary flow, Supercritical n-decane, Thermal diffusion, Velocity strains
- in
- International Journal of Thermal Sciences
- volume
- 168
- article number
- 107066
- publisher
- Elsevier
- external identifiers
-
- scopus:85107115264
- ISSN
- 1290-0729
- DOI
- 10.1016/j.ijthermalsci.2021.107066
- language
- English
- LU publication?
- yes
- id
- ebb9d384-2488-42ce-9dbb-002ccabbb5b0
- date added to LUP
- 2021-06-22 11:19:43
- date last changed
- 2023-11-08 15:43:03
@article{ebb9d384-2488-42ce-9dbb-002ccabbb5b0,
abstract = {{<p>In this paper, we consider the flow and heat transfer behaviour of turbulent upward and downward flows of supercritical n-decane, in order to reveal the features of heat transfer deterioration (HTD) that would be expected in relevant active regenerative cooling systems for scramjet engines. Specific focus is placed on key velocity-field features that appear in these flows. Following the validation of six turbulence models, the SST k-ω and RNG k-ϵ models are found to be suitable for simulating the upward and downward flow cases, respectively. “M” type velocity profiles (a non-monotonicity of the velocity along the radial direction) are observed, which arise due to a spatially-varying interplay between the inertial and viscous forces in the flow domain, while larger velocity gradients in the buffer layer are also observed that contribute to the phenomenon of HTD. Furthermore, it is found that the secondary flows as well as the different mass fluxes that arise due to the velocity increase from the wall to the flow core zone (i.e., the influencing range and intensity of cross-sectional kinetic energy), respectively, are observed in the HTD development region, as well as the HTD peak area and degradation regions. A zone of higher thermal diffusion appears in the near-wall region, which acts as a thermal barrier and contributes to HTD.</p>}},
author = {{Li, Yong and Markides, Christos N. and Sunden, Bengt and Xie, Gongnan}},
issn = {{1290-0729}},
keywords = {{Heat transfer deterioration; Secondary flow; Supercritical n-decane; Thermal diffusion; Velocity strains}},
language = {{eng}},
month = {{10}},
publisher = {{Elsevier}},
series = {{International Journal of Thermal Sciences}},
title = {{Heat transfer deterioration in upward and downward pipe flows of supercritical n-decane for actively regenerative cooling}},
url = {{http://dx.doi.org/10.1016/j.ijthermalsci.2021.107066}},
doi = {{10.1016/j.ijthermalsci.2021.107066}},
volume = {{168}},
year = {{2021}},
}