Measurement of diffusion and thermal diffusion in ternary fluid mixtures using a two-color optical beam deflection...

Area of Science:

• Physical Chemistry
• Chemical Engineering
• Fluid Dynamics

Background:

• Understanding multicomponent diffusion and thermal diffusion is crucial for various chemical processes.
• Existing methods for ternary mixtures can be complex and lack precision.

Purpose of the Study:

• To develop and validate a highly sensitive two-color beam deflection technique for measuring transport properties in ternary fluid mixtures.
• To determine diffusion matrices, thermal diffusion, and Soret coefficients for specific ternary mixtures.

Main Methods:

• Utilized a novel two-color beam deflection setup for simultaneous measurement of two laser beams.
• Employed a numerical model coupled with nonlinear least-squares fitting to analyze coupled heat and mass transport equations.
• Incorporated thermal diffusion forced Rayleigh scattering experiments to refine results.

Main Results:

• Successfully measured time-dependent concentration profiles for all three components in ternary mixtures.
• Obtained diffusion matrix, thermal diffusion, and Soret coefficients using the developed numerical model.
• Achieved independent determination of three Soret coefficients from stationary beam deflection amplitudes.

Conclusions:

• The developed two-color beam deflection method provides a sensitive and accurate approach for studying transport phenomena in ternary fluid mixtures.
• Measurements on specific ternary mixtures showed partial agreement with existing literature data, highlighting the need for further validation.
• The technique offers a robust pathway for characterizing complex fluid systems.