Calibration of micro-encapsulated liquid crystals using hue angle and a dimensionless temperature

Hay, Jennifer L.; Hollingsworth, D. Keith

doi:10.1016/s0894-1777(98)10026-2

Cited by 48 publications

(21 citation statements)

References 6 publications

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“…Color image acquisition system based on three basic colors R, G and B was used in the investigations. When the liquid crystals calibration and the measurements take place in identical and constant geometrical and lighting conditions, the HSI system allows conversion of three-component RGB signal into a single hue matrix [13,26]. RGB components of the color image of any pixel of the observed surface with variable temperature recorded by the measurement system, Fig.…”

Section: What Are We Trying To Findmentioning

confidence: 99%

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Boiling heat transfer in vertical minichannels. Liquid crystal experiments and numerical investigations

Hożejowska

Piasecka

Poniewski

2009

International Journal of Thermal Sciences

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Section: What Are We Trying To Findmentioning

confidence: 99%

“…It is assumed that, similar to [13], the mean temperature error for a single point determined on the basis of hue in the calibration experiment, amounts to:…”

Section: Foil Temperaturementioning

confidence: 99%

Boiling heat transfer in vertical minichannels. Liquid crystal experiments and numerical investigations

Hożejowska

Piasecka

Poniewski

2009

International Journal of Thermal Sciences

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“…The course of calculations used for the evaluation of the accuracy of heating foil temperature measurements with liquid crystals thermography is presented in [1]. Similarly to [1,8], it is assumed that the mean temperature error for the single point, determined on the basis of hue in calibration experiment, amounts to:…”

Section: Evaluation Of the Accuracy Of Heating Foil Temperature Measumentioning

confidence: 99%

Equalizing calculus in Trefftz method for solving two-dimensional temperature field of FC-72 flowing along the minichannel

Hożejowska

Piasecka

2014

Heat Mass Transfer

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The paper focuses on the numerical solution to two-dimensional temperature field of boiling liquid flowing along a vertical, asymmetrically heated minichannel with a rectangular cross-section. One of the walls of a minichannel is DC supplied single-sided enhanced foil with mini-recesses distributed unevenly in the selected area. The parallel walls are made of glass panes for thermal insulation and they are intended for observation of the two-phase flow and the void fraction. The thin layer of thermosensitive liquid crystal paint on the outer side of the foil enabled to record two-dimensional temperature distribution of outer foil surface. The paper described computations based on Trefftz method for finding two-dimensional temperature field of boiling liquid flowing along the minichannel. The presented research is limited only to the liquid phase of the two-phase mixture observed in the minichannel. The velocity of liquid flowing through the minichannel is represented by a piecewise linear approximating function. To solve energy equation for liquid phase, Trefftz functions specially generated for this purpose were employed. Temperature field in the fluid was approximated by a linear combination of Trefftz functions. Equalizing calculus was applied to the Trefftz method to smooth temperature measurements and reduce measurement errors.Temperature at the interface between working fluid and foil amounts to the saturation temperature. Temperature distribution in the foil and the glass pane was also computed using proper Trefftz functions. List of symbols

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“…7b. Hue in the polar coordinate system represents the wavelength of the dominant color and is defined as an angle in the following way [4,5,7,18]:…”

Section: Selected Color Models Algorithm Of Color Image Acquisition mentioning

confidence: 99%

“…Similarly to [4,6,18], it is assumed that the mean temperature error for the single point, determined on the basis of hue in the calibration experiment, amounts to:…”

Section: Evaluation Of the Accuracy Of Heating Foil Temperature Measumentioning

confidence: 99%

Determination of the Temperature Field Using Liquid Crystal Thermography and Analysis of Two-Phase Flow Structures in Research on Boiling Heat Transfer in a Minichannel

Piasecka¹

2013

Metrology and Measurement Systems

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The paper presents the application of liquid crystal thermography for temperature determination and visualisation of two phase flow images on the studied surface. Properties and applications of thermochromic liquid crystals are discussed. Liquid crystals were applied for two-dimensional detection of the temperature of the heating foil forming one of the surfaces of the minichannel along which the cooling liquid flowed. The heat flux supplied to the heating surface was altered in the investigation and it was accompanied by a change in the color distribution on the surface. The accuracy of temperature measurements on the surface with liquid crystal thermography is estimated. The method of visualisation of two-phase flow structures is described. The analysis of monochrome images of flow structures was employed to calculate the void fraction for some cross-sections. The flow structure photos were processed using Corel graphics software and binarized. The analysis of phase volumes employed Techsystem Globe software. The measurement error of void fraction is estimated.

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Calibration of micro-encapsulated liquid crystals using hue angle and a dimensionless temperature

Cited by 48 publications

References 6 publications

Boiling heat transfer in vertical minichannels. Liquid crystal experiments and numerical investigations

Boiling heat transfer in vertical minichannels. Liquid crystal experiments and numerical investigations

Equalizing calculus in Trefftz method for solving two-dimensional temperature field of FC-72 flowing along the minichannel

Determination of the Temperature Field Using Liquid Crystal Thermography and Analysis of Two-Phase Flow Structures in Research on Boiling Heat Transfer in a Minichannel

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