HFS Heat Flux Sensor Instruction Manual
7
Take the sensor’s temperature measurement, T
°C
, at each measurement in time
along with the calibrated sensitivity, S
Calib
, to determine the heat flux sensitivity at that
specific temperature, S
@ T
°C
.
𝑆
@
𝑇℃
=
𝑀
.
𝐹.∗ 𝑆
𝐶𝑎𝑙𝑖𝑏
= [0.00334 ∗ 𝑇
℃
+ 0.917 ] ∗ 𝑆
𝐶𝑎𝑙𝑖𝑏
Calculating Heat Flux
Using the DC voltage measurements taken from the heat flux wire leads (white &
bright red), the heat flux values can be calculated using the adjusted sensitivity for that
specific sensor and the following equation.
where
q”
is the heat flux absorbed through the sensor,
∆V
q”
is the HFS sensor output heat
flux voltage, and S
@ T
°C
. is the sensitivity of the sensor that has been adjusted according
to the sensor’s temperature at that specific time.
For example:
A voltage value of 1.80 mV is measured across the heat flux
leads, and the sensor’s calibrated sensitivity is specified to equal 0.90 µV/(W/m
2
),
and the sensor’s temperature is measured to be equal to 30°C from the
thermocouple leads at that point in time. The calculation for heat flux is as follows.
1.
First, adjust the sensitivity according to the measured sensor temperature
from the sensor’s integrated Type-T thermocouple. (Ignore this step if using
the UHFS-09 sensor).
M.F. = 0.00334*T
°
C
+ 0.917
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
-50
-30
-10
10
30
50
70
90
110
130
Sensor Temperature (°C)
Sensitivity Multiplication Factor Versus
Sensor Temperature (25
°
C Origin)
