Hukseflux Blk series User manual

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.

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Figure 0.2 Working with BLK - GLD stickers: measuring the radiative and convective

heat fluxes on an espresso machine.

BLK – GLD stickers are easy to use:

They are designed to be applied by the user but can optionally also be pre-applied at the

factory. Applying a sticker to a heat flux sensor does not change the sensitivity of the

sensor, so no additional calibration is required. Using the reliable measurement technology

behind our heat flux sensors, separating convective and radiative heat flux has never been

easier.

Figure 0.3 BLK – GLD sticker series is a range of accessories for use with Hukseflux heat

flux sensors of the FHF05 series and HFP01. The stickers have matching sizes and are

designed to be applied by the user to the sensor.

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There is restriction to use BLK and GLD stickers: in particular if there is a notable amount

of solar radiation, the GDL sticker will absorb a significant part of it.

NOTICE

Treat BLK and GLD stickers with care. Avoid abrasive action. Clean gently with

soft cloth and if needed with demi-water. The gold layer of the GLD sticker is

extremely thin and may easily be rubbed off.

NOTICE

The GLD sticker will not perfectly reflect radiation from sources with

blackbody temperature higher than 4000 K. Solar radiation is in this category.

When in doubt, consult this manual or Hukseflux.

See also:

•BLK – GLD sticker application instruction video on our YouTube channel

•FHF05 series general-purpose heat flux sensor

•FHF05SC series a self-calibrating version of the FHF05 series

•model HFP01 for increased sensitivity

•heater HTR02 series, for calibration and verification of performance of FHF-type

sensors

•view our complete range of heat flux sensors

Figure 0.4 Overview of BLK-GLD stickers series: black absorbing stickers and gold

reflective stickers matching FHF05 series and HFP01 heat flux sensors. They are designed

to be applied by the user but can optionally also be pre-applied at the factory. The figure

shows, from left to right, the stickers GLD and BLK on FHF05-10X10, FHF05-15X30,

FHF05-50X50, FHF05-15X85 and FHF05-85X85. BLK-GLD sticker series is also available

for model HFP01 and FHF05SC series.

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1Ordering and checking at delivery

1.1 Ordering BLK – GLD stickers

The BLK – GLD sticker series is a range of accessories for use with Hukseflux heat flux

sensors of FHF05(SC) series and HFP01.

The ordering codes of the different versions in the series are BLK-10X10, BLK-15X30, BLK-

50X50, BLK-15X85, BLK-85x85, BLK-80, GLD-10X10, GLD-15X30, GLD-50X50, GLD-

15X85, GLD-85X85 and GLD-80.

Table 1.1.1 Overview of versions in the BLK – GLD sticker series

BLK versions

BLK-10X10