Advanced

Heat flux reconstruction by inversion of experimental infrared temperature measurements – Application to the impact of a droplet in the film boiling regime

Chaze, W. LU ; Caballina, O. ; Castanet, G. ; Pierson, J. F. ; Lemoine, F. and Maillet, D. (2019) In International Journal of Heat and Mass Transfer 128. p.469-478
Abstract

An Inverse Heat Conduction Problem (IHCP) is considered in order to estimate the transient heat flux extracted from a hot solid surface by an impinging droplet. The resolution of the IHCP is made with the so-called quadrupole method, which provides an analytical expression of the temperature and the heat flux at the front surface of the solid wall, where the drop impact takes place. In the experiments, the thermal response of the front surface is recorded using IR thermography. For that, sapphire is chosen as the material of the solid wall, and the front surface is coated with a thin TiAlN ceramic layer (thickness of 300 nm). The latter is highly emissive and opaque in the IR while sapphire is transparent at the same wavelengths. This... (More)

An Inverse Heat Conduction Problem (IHCP) is considered in order to estimate the transient heat flux extracted from a hot solid surface by an impinging droplet. The resolution of the IHCP is made with the so-called quadrupole method, which provides an analytical expression of the temperature and the heat flux at the front surface of the solid wall, where the drop impact takes place. In the experiments, the thermal response of the front surface is recorded using IR thermography. For that, sapphire is chosen as the material of the solid wall, and the front surface is coated with a thin TiAlN ceramic layer (thickness of 300 nm). The latter is highly emissive and opaque in the IR while sapphire is transparent at the same wavelengths. This feature allows the surface impacted by the droplet to be viewed from the bottom by the IR camera. This approach has been implemented to gain some insights into the heat transfer from the solid surface as well as the formation and growth of the vapor film, which appears under the droplet in the regime of film boiling, when the solid temperature is much higher than the boiling temperature of the liquid. Due to the small thickness of the vapor film, heat conduction is predominant in the vapor layer. Hence, the thickness of the vapor film can be deduced from the value of the reconstructed local heat flux, assuming a linear profile of temperature between the liquid interface of the droplet at the saturation temperature and the solid surface measured by IR thermometry.

(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
Drop impact, Film boiling, Inverse Heat Conduction Problem, IR thermography, Vapor layer
in
International Journal of Heat and Mass Transfer
volume
128
pages
10 pages
publisher
Pergamon
external identifiers
  • scopus:85053082726
ISSN
0017-9310
DOI
10.1016/j.ijheatmasstransfer.2018.08.069
language
English
LU publication?
yes
id
761ad94d-2df9-410b-acc5-40a8f2cb039a
date added to LUP
2018-10-08 09:52:09
date last changed
2020-03-24 06:24:37
@article{761ad94d-2df9-410b-acc5-40a8f2cb039a,
  abstract     = {<p>An Inverse Heat Conduction Problem (IHCP) is considered in order to estimate the transient heat flux extracted from a hot solid surface by an impinging droplet. The resolution of the IHCP is made with the so-called quadrupole method, which provides an analytical expression of the temperature and the heat flux at the front surface of the solid wall, where the drop impact takes place. In the experiments, the thermal response of the front surface is recorded using IR thermography. For that, sapphire is chosen as the material of the solid wall, and the front surface is coated with a thin TiAlN ceramic layer (thickness of 300 nm). The latter is highly emissive and opaque in the IR while sapphire is transparent at the same wavelengths. This feature allows the surface impacted by the droplet to be viewed from the bottom by the IR camera. This approach has been implemented to gain some insights into the heat transfer from the solid surface as well as the formation and growth of the vapor film, which appears under the droplet in the regime of film boiling, when the solid temperature is much higher than the boiling temperature of the liquid. Due to the small thickness of the vapor film, heat conduction is predominant in the vapor layer. Hence, the thickness of the vapor film can be deduced from the value of the reconstructed local heat flux, assuming a linear profile of temperature between the liquid interface of the droplet at the saturation temperature and the solid surface measured by IR thermometry.</p>},
  author       = {Chaze, W. and Caballina, O. and Castanet, G. and Pierson, J. F. and Lemoine, F. and Maillet, D.},
  issn         = {0017-9310},
  language     = {eng},
  month        = {01},
  pages        = {469--478},
  publisher    = {Pergamon},
  series       = {International Journal of Heat and Mass Transfer},
  title        = {Heat flux reconstruction by inversion of experimental infrared temperature measurements – Application to the impact of a droplet in the film boiling regime},
  url          = {http://dx.doi.org/10.1016/j.ijheatmasstransfer.2018.08.069},
  doi          = {10.1016/j.ijheatmasstransfer.2018.08.069},
  volume       = {128},
  year         = {2019},
}