Binary Diffusion Coefficients for Combustion Modeling
William S. McGivern, Jeffrey A. Manion
Recent studies have demonstrated that combustion models can be as sensitive to the binary diffusion coefficients of the fuel species as to the kinetics of major chemical reactions. We have constructed a reversed-flow chromatographic apparatus for the measurement of binary diffusion coefficients of hydrocarbons, detected using flame ionization detection, and inert species detected by thermal conductivity. We have measured the binary diffusion coefficients for several systems at temperatures from (300-723) K. The system is characterized by determining the binary diffusion coefficients of dilute argon in helium and dilute helium in argon as well as nitrogen in helium using a thermal conductivity detector. The diffusion of dilute methane in helium has been measured using the flame ionization detection and found to be in excellent agreement with literature values. Comparison of the measurements and simulations of the output of the diffusion column in the reversed-flow system show dependences on diffusion time and injection volume that must be considered to ensure accurate diffusion coefficients.
Proceedings of the 6th U.S. Combustion Institute Meeting