Scanning liquid-crystal thermometry and stereo velocimetry for simultaneous three-dimensional measurement of temperature and velocity field in a turbulent Rayleigh-B�rnard convection

Fujisawa, Nobuyuki; Funatani, Shumpei; Katoh, Noriyuki

doi:10.1007/s00348-004-0891-2

Cited by 46 publications

(28 citation statements)

References 20 publications

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“…Normally, heating from the bottom and sides of the cup causes thermal convection, which promotes mixing of the fluid inside, and results in a uniform temperature field [9][10][11][12][13]. Therefore, the magnitude of the thermal convection is a key to understanding the temperature fields in the cup and the accuracy of the viscosity measurement in the vibrational viscometer.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermal Convection on Viscosity Measurement in Vibrational Viscometer

Akpek¹,

Youn²,

Maeda³

et al. 2014

JFCMV

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This paper describes the experimental study of viscosity measurement error in the vibrational type viscometer, which measures viscous damping of the oscillating circular plate in a fluid in continuously increasing temperatures. The experiments are carried out to measure non-uniformity of the temperature field in the test cup of the vibrational viscometer in continuously increasing temperatures, while changing the viscosity of the target fluids. Experimental outcomes show that non-uniformity of the temperature grows in the cup and results in viscosity measurement error, when the viscosity of the fluid increases. In order to understand this phenomenon, velocity measurement by particle image velocimetry is conducted in the test cup for fluids of varying viscosity. The results indicate that mixing is enhanced in the low-viscosity fluid by the occurrence of unsteady thermal convection, while weaker convection appears in the high-viscosity fluid.

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Section: Introductionmentioning

confidence: 99%

Effect of Thermal Convection on Viscosity Measurement in Vibrational Viscometer

Akpek¹,

Youn²,

Maeda³

et al. 2014

JFCMV

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“…They state that there is a clear advantage to using the S and I image data, in addition to H, and reported an uncertainty of 0.06 K in a range of 2.3 K (2.6 %), evaluating the average temperature in interrogation windows. Fujisawa et al (2005) later reported uncertainty values of 0.13 K, using a stereoscopic setup (also 2D interrogation windows), on TLCs with a temperature response range of 2.3 K (5.7 %), also calibrating temperature with all three variables. Note that all of the research done up to this point has been performed using mean color values, calculated over designated areas of the sensor, and not individually for each tracer particle.…”

Section: Calibrationmentioning

confidence: 99%

“…Fujisawa and Hashizume (2001) performed a study of synthetical data, using a multi-variable calibration approach, and reported uncertainty values of 0.06 K in a range of 2.3 K (2.6 %) for two-dimensional interrogation windows. Fujisawa et al (2005) later reported uncertainty values of 0.13 K, using a stereoscopic setup, on TLCs with a temperature response range of 2.3 K (5.7 %), using a similar approach. It should be noted, however, that even though the HSI color space has been the transformation of choice for most research groups using this measurement technique, it is not the only means of interpreting color of digital images in order to extract their temperature information.…”

Section: Introductionmentioning

confidence: 99%

“…Up to this day, all of the reports on this flow diagnostics technique are based on acquiring color images of flows, with high concentrations of TLC material, and reconstructing planar temperature fields. Extensions of this principle like scanning methods (Fujisawa and Funatani 2000;Fujisawa et al 2005;Lutjen et al 2001) and stereoscopic arrangements (Funatani and Fujisawa 2002;Fujisawa et al 2004Fujisawa et al , 2005 have also been used to reconstruct three-dimensional temperature flow fields. All of these measurements rely on the concept of breaking the color images into sections and evaluating the mean temperature of the flow in each section.…”

Section: Introductionmentioning

confidence: 99%

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Non-encapsulated thermo-liquid crystals for digital particle tracking thermography/velocimetry in microfluidics

Segura

Cierpka

Rossi

et al. 2012

Microfluid Nanofluid

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The ever accelerating state of technology has powered an increasing interest in heat transfer solutions and process engineering innovations in the microfluidics domain. In order to carry out such developments, reliable heat transfer diagnostic techniques are necessary. Thermo-liquid crystal (TLC) thermography, in combination with particle image velocimetry, has been a widely accepted and commonly used technique for the simultaneous measurement and characterization of temperature and velocity fields in macroscopic fluid flows for several decades. However, low seeding density, volume illumination, and low TLC particle image quality at high magnifications present unsurpassed challenges to its application to three-dimensional flows with microscopic dimensions. In this work, a measurement technique to evaluate the color response of individual non-encapsulated TLC particles is presented. A Shirasu porous glass membrane emulsification approach was used to produce the nonencapsulated TLC particles with a narrow size distribution and a multi-variable calibration procedure, making use of all three RGB and HSI color components, as well as the proper orthogonally decomposed RGB components, was used to achieve unprecedented low uncertainty levels in the temperature estimation of individual particles, opening the door to simultaneous temperature and velocity tracking using 3D velocimetry techniques.

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“…Such system is called combined TLC scanning stereo PIV. In this system, two parallel light-sheets are provided from metal halide lumps with rotary shutter mechanism (Fujisawa et al, 2005), which allows high intensity illumination for the measurement of velocity at various planar-sections in the three-dimensional flow field. Details of the pulse illumination system are described in Fujisawa et al (2005).…”

Section: Combined Tlc Piv Systemmentioning

confidence: 99%

Simultaneous imaging techniques for temperature and velocity fields in thermal fluid flows

Fujisawa

Funatani

Watanabe

2008

J Vis

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In this paper, non-intrusive imaging techniques for simultaneously measuring temperature and velocity fields of thermal liquid flows are described. The experimental methods for temperature imaging considered here are the thermo-sensitive liquid crystal tracers and the laser-induced fluorescence, which are combined with particle image velocimetry (PIV) to measure simultaneously the corresponding 2D and 3D velocity fields. The features of these experimental methods and characteristics are examined, covering the measurable temperature range, uncertainty of measurement, time response and so on. The successful examples of simultaneous measurement of temperature and velocity fields are described for turbulent Rayleigh-Bérnard convection of a horizontal fluid layer and turbulent buoyant plume issuing from a circular nozzle, and their physical mechanisms of transport phenomena are explained.

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Scanning liquid-crystal thermometry and stereo velocimetry for simultaneous three-dimensional measurement of temperature and velocity field in a turbulent Rayleigh-B�rnard convection

Cited by 46 publications

References 20 publications

Effect of Thermal Convection on Viscosity Measurement in Vibrational Viscometer

Effect of Thermal Convection on Viscosity Measurement in Vibrational Viscometer

Non-encapsulated thermo-liquid crystals for digital particle tracking thermography/velocimetry in microfluidics

Simultaneous imaging techniques for temperature and velocity fields in thermal fluid flows

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