Method and apparatus for implementing material thermal property measurement by flash thermal imaging
A method and apparatus are provided for implementing measurement of material thermal properties including measurement of thermal effusivity of a coating and/or film or a bulk material of uniform property. The test apparatus includes an infrared camera, a data acquisition and processing computer coupled to the infrared camera for acquiring and processing thermal image data, a flash lamp providing an input of heat onto the surface of a two-layer sample with an enhanced optical filter covering the flash lamp attenuating an entire infrared wavelength range with a series of thermal images is taken of the surface of the two-layer sample.
1. A method for implementing measurement of material thermal properties including measurement of thermal effusivity of a coating and/or film or a bulk material of uniform property comprising:
providing an infrared camera,
providing a data acquisition and processing computer coupled to the infrared camera for acquiring and processing thermal image data,
providing a flash lamp providing an input of heat onto the surface of a two-layer sample;
providing an optical filter covering the flash lamp for attenuating an entire infrared wavelength range of thermal images taken of the surface of a sample, providing said optical filter including a pair of glass plates enclosing a water layer; and
performing a measurement solution to determine material thermal properties including thermal effusivity of the sample.
2. The method as recited in claim 1 , includes providing two-layer sample, and measuring thermal effusivity of each of the two layers without requiring other material information.
3. The method as recited in claim 1 , wherein the measurement solution to determine material thermal properties including thermal effusivity of the sample is represented by:
T
f
(
t
)
=
Q
·
f
1
(
e
1
2
t
)
·
f
3
(
e
1
e
2
,
α
1
L
1
2
,
t
)
,
(
1
)
T
f
(
t
)
=
Q
ρ
1
c
1
L
1
+
ρ
2
c
2
L
2
·
f
4
(
e
1
e
2
,
α
1
L
1
2
,
α
2
L
2
2
,
t
)
,
(
2
)
where T ƒ (t) represents a front surface temperature, where t is time and Q is the total amount of absorbed energy (heat) on surface for the two-layer sample of materials of uniform properties with an instantaneous heat impulse for the cases of a semi-infinite and a finite substrate thickness material, respectively; where L represents sample thickness, e represents thermal effusivity and ρc represents heat capacity; where the subscripts 1 and 2 denote the first-layer or shallow layer material and a second-layer or deep layer material, respectively.
4. The method as recited in claim 1 , wherein performing a measurement solution to determines material thermal properties including thermal effusivity of the sample includes providing a measurement accuracy of <2% absolute errors.
5. The method as recited in claim 1 , wherein performing a measurement solution to determine material thermal properties including thermal effusivity of the sample includes measuring coating and/or film thermal effusivity with known substrate effusivity.
6. The method as recited in claim 1 , wherein performing a measurement solution to determines material thermal properties including thermal effusivity of the sample includes measuring thermal diffusivity of a bulk plate material with known plate thickness.
7. A method for implementing measurement of material thermal properties including measurement of thermal effusivity of a coating and/or film or a bulk material of uniform property comprising:
providing an infrared camera,
providing a data acquisition and processing computer coupled to the infrared camera for acquiring and processing thermal image data,
providing a flash lamp providing an input of heat onto the surface of a two-layer sample;
providing an optical filter covering the flash lamp for attenuating an entire infrared wavelength range of thermal images taken of the surface of a sample; and
performing a measurement solution to determine material thermal properties including thermal effusivity of the sample includes measuring thermal effusivity of a bulk material by bonding a calibrated film on a material surface of the bulk material.
8. A system for implementing measurement of material thermal properties including measurement of thermal effusivity of a coating and/or film or a bulk material of uniform property comprising:
an infrared camera,
a data acquisition and processing computer coupled to the infrared camera for acquiring and processing thermal image data,
a flash lamp providing an input of heat onto the surface of a two-layer sample;
an optical filter covering the flash lamp for attenuating an entire infrared wavelength range of thermal images taken of the surface of a sample, said optical filter including a pair of glass plates enclosing a water layer; and
said data acquisition and processing computer performing a measurement solution to determine material thermal properties including thermal effusivity of the sample.
9. The system as recited in claim 8 , wherein the sample includes a two-layer sample, and thermal effusivity of each of the two layers is measured without requiring other material information.
10. The system as recited in claim 9 , wherein the measurement solution to determine material thermal properties including thermal effusivity of the sample is represented by:
T
f
(
t
)
=
Q
·
f
1
(
e
1
2
t
)
·
f
3
(
e
1
e
2
,
α
1
L
1
2
,
t
)
,
(
1
)
T
f
(
t
)
=
Q
ρ
1
c
1
L
1
+
ρ
2
c
2
L
2
·
f
4
(
e
1
e
2
,
α
1
L
1
2
,
α
2
L
2
2
,
t
)
,
(
2
)
where T ƒ (t) represents a front surface temperature, where t is time and Q is the total amount of absorbed energy (heat) on surface for the two-layer sample of materials of uniform properties with an instantaneous heat impulse for the cases of a semi-infinite and a finite substrate thickness material, respectively; where L represents sample thickness, e represents thermal effusivity and ρc represents heat capacity; where the subscripts 1 and 2 denote the first-layer or shallow layer material and a second-layer or deep layer material, respectively.
11. The system as recited in claim 8 , wherein said data acquisition and processing computer performing a measurement solution to determine material thermal properties including thermal effusivity of the sample provides a measurement accuracy of <2% absolute errors.
12. The system as recited in claim 8 , wherein said data acquisition and processing computer performing a measurement solution to determine material thermal properties including thermal effusivity of the sample includes said data acquisition and processing computer measuring coating and/or film thermal effusivity with known substrate effusivity.
13. The system as recited in claim 8 , wherein said data acquisition and processing computer performing a measurement solution to determine material thermal properties including thermal effusivity of the sample includes said data acquisition and processing computer measuring thermal effusivity of a bulk material by bonding a calibrated film on a material surface of the bulk material.
14. The system as recited in claim 8 , wherein said data acquisition and processing computer performing a measurement solution to determine material thermal properties including thermal effusivity of the sample includes said data acquisition and processing computer measuring thermal diffusivity of a bulk plate material with known plate thickness.