Advanced

The abnormal heat transfer behavior of supercritical n-decane flowing in a horizontal tube under regenerative cooling for scramjet engines

Chen, Youqian ; Li, Yong LU ; Sunden, Bengt LU and Xie, Gongnan LU (2020) In Applied Thermal Engineering 167.
Abstract

This paper aims to describe the reasons why abnormal heat transfer occurs under the condition of regenerative cooling applied in scramjet engines. Supercritical n-decane flowing in a horizontal tube under various mass flow rates (G = 0.001, 0.002, 0.003, 0.004 kg/s) and heat fluxes (qw = 100, 200, 300, 400 kW/m2) is investigated by numerical simulations. The mechanisms of the abnormal heat transfer were explained from the perspective of thermal diffusivity, velocity and the process of vortex evolution. The great temperature difference generated by the extreme operating condition (low mass flow rate and large heat flux) contributes to the higher buoyancy force inside the tube. Several interesting phenomena are found... (More)

This paper aims to describe the reasons why abnormal heat transfer occurs under the condition of regenerative cooling applied in scramjet engines. Supercritical n-decane flowing in a horizontal tube under various mass flow rates (G = 0.001, 0.002, 0.003, 0.004 kg/s) and heat fluxes (qw = 100, 200, 300, 400 kW/m2) is investigated by numerical simulations. The mechanisms of the abnormal heat transfer were explained from the perspective of thermal diffusivity, velocity and the process of vortex evolution. The great temperature difference generated by the extreme operating condition (low mass flow rate and large heat flux) contributes to the higher buoyancy force inside the tube. Several interesting phenomena are found due to the existence of the vortices and a very special one is the slight downturn when the wall temperature reaches the first maximum point. In addition, the basic principles of the abnormal heat transfer are represented by the regularity of the distribution of thermal diffusivity, and mainstream velocity. An important conclusion is that the thinner boundary layer of the flow generated by the high velocity in the mainstream direction is benefit for restraining the abnormal heat transfer.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Buoyancy, Horizontal tube, Slight downturn, Supercritical n-decane, Vortex dissipation
in
Applied Thermal Engineering
volume
167
article number
114637
publisher
Elsevier
external identifiers
  • scopus:85075343632
ISSN
1359-4311
DOI
10.1016/j.applthermaleng.2019.114637
language
English
LU publication?
yes
id
7b275f3a-6763-4851-8c0b-c51fdf622222
date added to LUP
2019-12-10 12:33:04
date last changed
2020-02-25 04:30:00
@article{7b275f3a-6763-4851-8c0b-c51fdf622222,
  abstract     = {<p>This paper aims to describe the reasons why abnormal heat transfer occurs under the condition of regenerative cooling applied in scramjet engines. Supercritical n-decane flowing in a horizontal tube under various mass flow rates (G = 0.001, 0.002, 0.003, 0.004 kg/s) and heat fluxes (q<sub>w</sub> = 100, 200, 300, 400 kW/m<sup>2</sup>) is investigated by numerical simulations. The mechanisms of the abnormal heat transfer were explained from the perspective of thermal diffusivity, velocity and the process of vortex evolution. The great temperature difference generated by the extreme operating condition (low mass flow rate and large heat flux) contributes to the higher buoyancy force inside the tube. Several interesting phenomena are found due to the existence of the vortices and a very special one is the slight downturn when the wall temperature reaches the first maximum point. In addition, the basic principles of the abnormal heat transfer are represented by the regularity of the distribution of thermal diffusivity, and mainstream velocity. An important conclusion is that the thinner boundary layer of the flow generated by the high velocity in the mainstream direction is benefit for restraining the abnormal heat transfer.</p>},
  author       = {Chen, Youqian and Li, Yong and Sunden, Bengt and Xie, Gongnan},
  issn         = {1359-4311},
  language     = {eng},
  month        = {02},
  publisher    = {Elsevier},
  series       = {Applied Thermal Engineering},
  title        = {The abnormal heat transfer behavior of supercritical n-decane flowing in a horizontal tube under regenerative cooling for scramjet engines},
  url          = {http://dx.doi.org/10.1016/j.applthermaleng.2019.114637},
  doi          = {10.1016/j.applthermaleng.2019.114637},
  volume       = {167},
  year         = {2020},
}