Differential molecular diffusion effects in turbulent mixing

R. W. Bilger, R. W. Dibble

Research output: Contribution to journalArticlepeer-review

86 Scopus citations


The differential diffusion of two species in a turbulent mixing flow is considered. In flows of moderate Reynolds number molecular diffusivities can te a subtantial fraction of the effective turbulent diffusivity and significant differential diffusion can result for species with widely different molecular diffusivities. A theory is presented for the mean and second moments of concentration difference and results are reported for computations for a jet of hydrogen and propane mixing with air. An experiment using Rayleigh scattering to detect the differential diffusion is suggested. Differential diffusion is considered to be very significant in turbulent diffusion flames where molecular and thermal diffusivities are large at high temperatures.

Original languageEnglish (US)
Pages (from-to)161-172
Number of pages12
JournalCombustion science and technology
Issue number3-4
StatePublished - Jun 1 1982
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • General Physics and Astronomy


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