Compressibility Effects on the Scalar Dissipation Rate

John Panickacheril John, Diego A. Donzis, Katepalli R. Sreenivasan

Research output: Contribution to journalArticle

Abstract

Scalar dissipation rate plays an important role in combustion, especially for fast chemistry in non-premixed flames. Even for finite-rate chemistry, it is a parameter of major importance in models based on flamelets, probability density function methods, and conditional moment closures. Compressibility can influence the behavior of scalar dissipation but existing models do not consider them in the form of large dilatational effects, which are present in combustion in high-speed propulsion systems such as scramjets in hypersonic flight. This paper considers these effects on the scalar dissipation rate, in particular its mean value, spectral density, probability density function, as well the alignment of the scalar gradient with the strain field of the flow. The major result of this study is that the majority of the compressibility effects on inertial-type scales can be taken into account if the classical scaling laws of incompressible turbulence are rescaled by taking only the solenoidal contributions. However, additional effects of compressibility need to be considered at smaller scales.

Original languageEnglish (US)
Pages (from-to)1320-1333
Number of pages14
JournalCombustion Science and Technology
Volume192
Issue number7
DOIs
StatePublished - Jul 2 2020

Keywords

  • Scalar dissipation
  • combustion
  • compressibility effects
  • flames

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Physics and Astronomy(all)

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