H u k s e f l u x T h e r m a l S e n s o r s
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2General Theory
The HF03’s main component is a heat flux sensor. The sensor is
located under the black surface on the front of the HF03. It is
mounted on a metal heat sink, which is in turn protected by a
plastic housing. The heat flux sensor generates a small voltage
signal that is a linear function of the incoming radiant and
convective heat flux.
Using HF03 is easy. For readout, one only needs an accurate
voltmeter that works in the millivolt range. To convert the
measured voltage Vsen to a heat flux , the voltage must be
divided by the sensitivity Esen, a constant that is supplied with
each individual sensor.
= Vsen / Esen 2.1
The sensitivity of HF03 is supplied with each individual
instrument, and can be found on its calibration certificate.
HF03 is read-out by LI19, which essentially is a voltmeter in
which a calibration factor can be entered, to show watt per meter
square.
Expected accuracy:
The expected accuracy of a measurement with HF03 depends on
many factors, but most of all on:
1 the intensity of the radiation
2 wind effects
HF03 is calibrated with a radiant source under conditions of
“natural convection” i.e. no wind.
The wind can play a large role in determining the end result of
the heat flux measurement, and also in discrepancies between
measurement results of one sensor type and another because
surface temperatures on different sensors will deviate from each
other. The quantification of this effect is strongly dependent on
the circumstances. However, deviations of up to 20% have been
reported for different sensor designs, although these were
calibrated under the same conditions.
