Conditional moment closure modeling of turbulent nonpremixed combustion in diluted hot coflow

Seung Hyun Kim, Kang Y. Huh*, Bassam Dally

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

102 Scopus citations

Abstract

The conditional moment closure (CMC) model is applied to predict flame structures and NO formation in the moderate and intense low oxygen dilution combustion mode. The effects of oxygen concentration in a hot diluted oxidant stream are investigated in the experimental condition of Dally et al. [Proc. Combust. Inst. 29 (2002) 1147-1154]. The GRI 2.11 Mech is used for description of chemical reaction including NOx chemistry. The conditional scalar dissipation rate, which describes the effect of turbulent mixing on finite chemistry, is calculated by integrating the transport equation for probability density function (PDF). A new PDF is proposed to describe three stream mixing in terms of a single mixture fraction. The conditional mean predictions of temperature, and CO, OH, and NO mass fractions are in good agreement with measurements. The unconditional Favre mean predictions of CO and NO mass fractions are also in reasonable agreement. Upstream underprediction of OH and NO in the low oxygen concentration case may be attributed to uncertainty in low temperature reaction mechanism and mixing prediction. Differential diffusion effects are shown to be nonnegligible in the present flames. The CMC model is an attractive choice for simulation of MILD combustion in which conditional fluctuations of reactive scalars are small enough for first-order closure of conditional mean reaction rates to remain valid.

Original languageEnglish (US)
Pages (from-to)751-757
Number of pages7
JournalProceedings of the Combustion Institute
Volume30
Issue number1
DOIs
StatePublished - 2005
Event30th International Symposium on Combustion - Chicago, IL, United States
Duration: Jul 25 2004Jul 30 2004

Bibliographical note

Funding Information:
This work is supported by the BK21 project of the Ministry of Education and the Combustion Engineering Research Center at Korea Advanced Institute of Science and Technology.

Publisher Copyright:
© 2004 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Keywords

  • CMC
  • MILD combustion
  • Turbulent nonpremixed flames

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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