C-THERM TCi Operator's Manual page 103

C is the 1/m value for vacuum.
C

e W
(
1
M
e , sensor effusivity can be calculated from (20).
1
In practice, for high effusivity (high k) materials equation (13) is inaccurate, because the heat
flows also laterally and the one-dimensional heat flow assumption is no longer satisfied.
Equations (13), (14) and (15) are only approximate.
A better representation of this case can be achieved by a second order polynomial
approximation. Example of sensor effusivity calibration curve using metals is given below.
This curve can be mathematically described (instead of (17)) as:
1
   
2
M e M
2 2 1
m
Where M and M describe the curve of the effusivity calibration and are proportional to:
2 1
1

M
 
1
I A G
And C is the same expression as in (17), i.e. 1/m value for vacuum.
Equation (21) is deducted empirically.

2
s m C
)

e C
2
  
2
m C W Amp
(
(20)

)
TCi Operator Manual
(21)
(22)
97