Thermal Imaging Through Liquid Media

[BespinSunset]

I have some questions about the limits of using thermal imagers to map the heat released due to material deformations of solids surrounded in a liquid media.

1) Can thermal imagers be used to make accurate assessments in liquid media?

2) What are the factors which limit the media between camera and object?

3) What limits the operating temperature of Thermal Imagers? and what limits their measuring range?

4) In the specific case of making measurements at extremely low temperatures of say -180C, and SUPPOSING the measuring device were capable of measuring these kind of temperatures, would the low temperature medium between the camera and the object being measured cause problems with obtaining a reliable image?

Cheers for any help,
Bespin

 

[IRstuff]

1) As a general rule, no. Water, as a example, does not transmit much IR.

2) Obviously, the absorption of the medium. Water's absorption coefficient is >10/cm above 3um, which, for all intents and purposes, a brick wall.

3,4) noise sources and internal temperature, which is essentially the same effect. Most infrared sensors used for thermography are cooled to 77 kelvin, which is -196°C, but is bombarded from all sides by thermal sources such as the vacuum dewar, optics emission, etc. In order to make accurate measurements at cold temperatures, you'll need to cool the optics and pretty much everything around the detector.

TTFN

 

[BespinSunset]

Thanks!

Yes, the camera we use is a JEOL7200, using liquid nitrogen as a coolant. I can appreciate what your saying.

If it were possible to monitor temperatures THROUGH a liquid coolant media, do you think that the cooling affects of the media on the specimen would effectively null the temperature increase due to plastic deformation?

Actually, I guess this question moves away from Infrared Imaging; It's more the effect of the coolant on temperature change of the specimen due to plastic deformation. Anyway...any ideas would be appreciated!

 

[IRstuff]

I'm not sure if plastic or any other deformation would have any significant impact at all.

The fact that your specimen is in contact with a liquid media means that both convective and conductive cooling from the media are in full force.

This means that the surface temperature of the specimen will indeed be affected by the media, regardless of any secondary effects.
TTFN

 

[BespinSunset]

Hi, Just wanted to drop in and say thanks for the tips. Most appreciated.