Hukseflux BLK Series User manual

Copyright by Hukseflux | manual v2214 | www.hukseflux.com | [e-mail]
USER MANUAL BLK -GLD
STICKER SERIES
Black and gold stickers for measuring
convective and radiative heat flux separately
Hukseflux
Thermal Sensors

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Cautionary statements
Cautionary statements are subdivided into four categories: danger, warning, caution and
notice according to the severity of the risk.
DANGER
Failure to comply with a danger statement will lead to death or serious
physical injuries.
WARNING
Failure to comply with a warning statement may lead to risk of death or
serious physical injuries.
CAUTION
Failure to comply with a caution statement may lead to risk of minor or
moderate physical injuries.
NOTICE
Failure to comply with a notice may lead to damage to equipment or may
compromise reliable operation of the instrument.

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Contents
Cautionary statements 2
Contents 3
List of symbols 4
Introduction 5
1Ordering and checking at delivery 8
1.1 Ordering BLK – GLD stickers 8
1.2 Included items 10
2Instrument principle and theory 11
2.1 Introduction 11
2.2 Normal use: moderate-accuracy and comparative measurements 13
3Advanced use: high-accuracy measurements 14
3.1 Introduction 14
3.2 Spectral properties of BLK and GLD stickers 14
3.3 BLK and GLD sensors on the same heat sink 16
3.4 BLK and GLD sensors at different temperatures 20
3.5 Surface temperature correction at high flux levels 21
3.6 Optional correction for sensor temperature dependence 23
3.7 Working with high colour temperature sources; the Sun, Xenon lamps 24
4Examples of BLK and GLD in use 25
4.1 Outgoing radiation heat flux on metallic / reflective surfaces 25
4.2 Sources covering part of the sensor field of view; the view factor 26
4.3 Heat flux measurement to characterise ovens, thermal profiling 28
5Specifications of BLK – GLD sticker series 32
5.1 Specifications of BLK – GLD stickers 32
5.2 Dimensions of BLK – GLD stickers 34
6Installation of BLK – GLD sticker series 36
6.1 Application procedure 36
6.2 Site selection and sensor installation 38
7Maintenance and trouble shooting 40
7.1 Recommended maintenance and quality assurance 40
7.2 Trouble shooting 42
7.3 Calibration and on-site checks 42
8Appendices 43
8.1 Reflection versus wavelength and source temperature 43
8.2 EU declaration of conformity 46

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List of symbols
Quantities Symbol Unit
Heat flux ΦW/m²
Voltage U V
Sensitivity S V/(W/m2)
Temperature T °C or K
Temperature dependence of sensitivity TD %/K
Thermal resistance per unit area Rthermal,A K/(W/m²)
Heat transfer coefficient by convection Ctr (W/m2)/K
Area A m2
Reflection factor r -
Absorbance α-
Emissivity ε-
Stefan-Boltzmann constant: 5.67 x 10-8 σW/m²·K4
Optical view factor f -
Angle of incidence θ°
Solid angle SA sr
Subscripts
Property of sensor sensor
Property of heat sink sink
Property of a radiative source source
Measured radiative heat flux radiative
Measured convective heat flux convective
Sensor with black sticker BLK
Sensor with gold sticker GLD
Property of ambient air air
Property of ambient environment ambient
Total total
Emitted radiative flux emitted
Incoming radiative flux at the sensor position incoming
Absorbed radiative flux absorbed
Reflected radiative flux reflected
Abbreviations
Ultraviolet UV
Visible light VIS
Near-infrared NIR
Far-infrared FIR

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Introduction
Heat flux measurement is a powerful tool to gain insights into processes involving
thermal energy. Heat is transported to an object by convection and radiation. Studying
thermal processes, the cause of temperature changes or heat transport, you may wish to
separate radiative and convective heat flux. This is now possible with the BLK – GLD
sticker series, designed to be used with a wide range of our market-leading heat flux
sensors. The BLK black stickers absorb all radiation and are sensitive to both radiative
and convective heat flux, while the GLD gold reflective stickers reflect all radiation and
are sensitive to convective heat flux only. Applying BLK and GLD stickers, on two
separate heat flux sensors, makes it possible to calculate the contributions of radiative
and convective heat flux:
Φradiative + Φconvective =Φtotal = ΦBLK
Φconvective = ΦGLD
Φradiative = ΦBLK −ΦGLD
BLK – GLD stickers have unique features and benefits:
•makes it possible to perform convective and radiative heat flux measurements
•available as accessory for the five models of the FHF05 series and HFP01 heat flux
sensors
•designed to be applied by the user
Figure 0.1 From left to right: model FHF05-50X50 heat flux sensor, FHF05-50X50 with
BLK-50X50 sticker, and FHF05-50X50 with GLD-50X50 sticker. BLK – GLD stickers are also
available for other dimensions of the FHF05 series and HFP01 heat flux sensors. The BLK
black absorbing stickers will absorb all radiation and are sensitive to both radiative and
convective heat flux, while the GLD gold reflective stickers reflect all radiation and are
sensitive to convective heat flux only.