Correlations of high-pressure lean methane and syngas turbulent burning velocities: Effects of turbulent Reynolds, Damköhler, and Karlovitz numbers

S. S. Shy, C. C. Liu, J. Y. Lin, L. L. Chen, A. N. Lipatnikov, S. I. Yang

Research output: Contribution to journalConference articlepeer-review

44 Scopus citations

Abstract

This paper investigates correlations of high-pressure turbulent burning velocities (ST) using our recent ST measurements of lean methane and syngas spherical flames at constant elevated pressures (p) and constant turbulent Reynolds numbers (ReT = u′ LI/ν), where u′, LI, and ν are the r.m.s. turbulent fluctuation velocity, the integral length scale of turbulence, and the kinematic viscosity of reactants, respectively. Such constant constraints are achieved by applying a very large high-pressure, dual-chamber explosion facility that is capable of controlling the product of u′ LI in proportion to the decreasing m due to the increase ofp. We have found that, contrary to popular scenario for ST enhancement with increasingp at any fixed u′, ST actually decreases similarly as laminar burning velocities (SL) with increasing p in minus exponential manners when values of ReT are kept constant. Moreover, ST increases noticeably with increasing ReT varying from 6700 to 14,200 at any constantp ranging from 1 atm to 10 atm. It is found that a better correlation for the normalization of ST is a power-law relation of ST/u′ = aDab where Da = (LI/u′)(SL/dF) is the turbulent Damköhler number, δF ≈ α/SL is the laminar flame thickness, and α is the thermal diffusivity of unburned mixture. Thus, the very scattering ST data for each of lean methane and syngas mixtures can be merged on their ST/u′ vs. Da curves with very small data fluctuations. For lean methane flames with the Lewis number (Le) ≈ 1, ST/u′ ≈ 0.12Da0.5. supporting a distributed reaction zone model anticipated by Ronney (1995), while for lean syngas flames with Le ≈ 0.76 < 1, ST/u′ ≈ 0.52Da0.25. supportinga theory predicted by Zimont (1979). A simple physical mechanism is proposed in attempt to explain what causes the aforesaid discrepancy on the power-law constants.

Original languageEnglish
Pages (from-to)1509-1516
Number of pages8
JournalProceedings of the Combustion Institute
Volume35
Issue number2
DOIs
StatePublished - 2015
Event30th International Symposium on Combustion - Chicago, IL, United States
Duration: 25 Jul 200430 Jul 2004

Keywords

  • Elevated pressure
  • Expanding spherical flames
  • Turbulent burning velocities
  • Turbulent Damköhler and Karlovitz numbers
  • Turbulent Reynolds number

Fingerprint

Dive into the research topics of 'Correlations of high-pressure lean methane and syngas turbulent burning velocities: Effects of turbulent Reynolds, Damköhler, and Karlovitz numbers'. Together they form a unique fingerprint.

Cite this