Water-Cooled Gardon Heat Flux Sensors

 Linear output
 Output directly proportional to heat
transfer rate
 Accurate, rugged, reliable
 Un-cooled models, water cooled models
 Radiometer and limited view accessories
 Measure total heat flux
 Measure radiant heat flux
heat flux sensors are of two basic
types: Gardon sensors and Schmidt-Boelter
sensors, both can provide a self-generated
EMF at the output leads that is directly
proportional to the heat transfer rate. No
power supply or thermoelectric reference
junction is needed.
Gardon sensor
The Gardon-type heat flux sensor consists of a
thin circular foil of constantan attached tightly
over a cooled copper annulus as shown in
Figure 1. The constantan foil forms two
junctions with copper. During thermal
exposure, a thermoelectric voltage, which is
directly proportional to the heat flux absorbed,
will be generated as a direct measure of the
temperature difference between the center and
the periphery of the constantan disk.
Schmidt-Boelter sensor
A special thermopile arrangement is wound on
a thin wafer, which imposes a thermal
resistance parallel to the direction of the heat
flux, forming temperature difference across
the hot and cold junctions, and thus generating
an output proportional to the heat flux, as
shown in Figure 2.