FEDSM2000-11043

Proceedings of ASME FEDSM’00 ASME 2000 Fluids Engineering Division Summer Meeting June 11-15, 2000, Boston, Massachusetts FEDSM2000-11043 DUAL EMISSION LASER INDUCED FLUORESCENCE TECHNIQUE (DELIF) FOR OIL FILM THICKNESS AND TEMPERATURE MEASUREMENT Carlos H. Hidrovo and Douglas P. Hart Massachusetts Institute of Technology Cambridge, MA 02139 ABSTRACT This paper presents the development and implementation of a Dual Emission Laser Induced Fluorescence (DELIF) technique for the measurement of film thickness and temperature of tribological flows. The technique is based on a ratiometric principle that allows normalization of the fluorescence emission of one dye against the fluorescence emission of a second dye, eliminating undesirable effects of illumination intensity fluctuations in both space and time. Although oil film thickness and temperature measurements are based on the same two-dye ratiometric principle, the required spectral dye characteristics and optical conditions differ significantly. The effects of emission reabsorption and optical thickness are discussed for each technique. Finally, calibrations of the system for both techniques are presented along with their use in measuring the oil film thickness and two-dimensional temperature profile on the lubricating film of a rotating shaft seal. INTRODUCTION Laser Induced Fluorescence (LIF) is based on the use of a light source to excite a fluorescence substance (fluorophore or fluorescent dye) that subsequently emits ligh...