Thermographic Particle Velocimetry (TPV) for Simultaneous Interfacial Temperature and Velocity Measurements
File(s)
Published version
Author(s)
Charogiannis, A
Markides, C
Zadrazil, I
Type
Journal Article
Abstract
We present an experimental technique, that we refer to as ‘thermographic particle velocimetry’ (TPV),
which is capable of the simultaneous measurement of two-dimensional (2-D) surface temperature and
velocity at the interface of multiphase flows. The development of the technique has been motivated by
the need to study gravity-driven liquid-film flows over inclined heated substrates, however, the same
measurement principle can be applied for the recovery of 2-D temperature- and velocity-field information
at the interface of any flow with a sufficient density gradient between two fluid phases. The proposed
technique relies on a single infrared (IR) imager and is based on the employment of highly reflective
(here, silver-coated) particles which, when suspended near or at the interface, can be distinguished from
the surrounding fluid domain due to their different emissivity. Image processing steps used to recover the
temperature and velocity distributions include the decomposition of each original raw IR image into separate
thermal and particle images, the application of perspective distortion corrections and spatial calibration,
and finally the implementation of standard particle velocimetry algorithms. This procedure is
demonstrated by application of the technique to a heated and stirred flow in an open container. In addition,
two validation experiments are presented, one dedicated to the measurement of interfacial temperature
and one to the measurement of interfacial velocity. The deviations between the results generated
from TPV and those from accompanying conventional techniques do not exceed the errors associated
with the latter.
which is capable of the simultaneous measurement of two-dimensional (2-D) surface temperature and
velocity at the interface of multiphase flows. The development of the technique has been motivated by
the need to study gravity-driven liquid-film flows over inclined heated substrates, however, the same
measurement principle can be applied for the recovery of 2-D temperature- and velocity-field information
at the interface of any flow with a sufficient density gradient between two fluid phases. The proposed
technique relies on a single infrared (IR) imager and is based on the employment of highly reflective
(here, silver-coated) particles which, when suspended near or at the interface, can be distinguished from
the surrounding fluid domain due to their different emissivity. Image processing steps used to recover the
temperature and velocity distributions include the decomposition of each original raw IR image into separate
thermal and particle images, the application of perspective distortion corrections and spatial calibration,
and finally the implementation of standard particle velocimetry algorithms. This procedure is
demonstrated by application of the technique to a heated and stirred flow in an open container. In addition,
two validation experiments are presented, one dedicated to the measurement of interfacial temperature
and one to the measurement of interfacial velocity. The deviations between the results generated
from TPV and those from accompanying conventional techniques do not exceed the errors associated
with the latter.
Date Issued
2016-03-01
Date Acceptance
2016-02-18
Citation
International Journal of Heat and Mass Transfer, 2016, 97, pp.589-595
ISSN
0017-9310
Publisher
Elsevier
Start Page
589
End Page
595
Journal / Book Title
International Journal of Heat and Mass Transfer
Volume
97
Copyright Statement
© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://
creativecommons.org/licenses/by/4.0/).
creativecommons.org/licenses/by/4.0/).
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/K008595/1
Subjects
Mechanical Engineering & Transports
01 Mathematical Sciences
09 Engineering
02 Physical Sciences
Publication Status
Published