Experimental study on radiation attenuation by a water film

- An optical method was used to measure water film thickness.
- Infrared radiation attenuation was derived from FTIR spectroscopic data.
- The shielding effect of water film was confirmed.
- Attenuation up to 95% was obtained for films less than 1 mm thick.

Radiative transfer through a water film was investigated. Films with average thicknesses between 100 and 380μm were studied. The film thickness was measured using an optical method based on the attenuation of a near infrared laser beam. The attenuation of infrared radiation on a wide spectral range was determined simultaneously by using a FTIR spectrometer. A high attenuation efficiency was observed even for such small film thicknesses, which demonstrated the shielding effect of water films. Extension of present observations to high temperature sources allows the evaluation of the film absorption, which was predicted in the range 60-95% for films between 100μm and 1 mm and for incident radiation from blackbodies up to 1473 K.