Linear-Eddy Modeling of Autoignition under Thermal Stratification
Please always quote using this URN: urn:nbn:de:0297-zib-10562
- The influence of thermal stratification on autoignition at constant volume and high pressure is investigated under turbulent conditions using the one-dimensional Linear-Eddy Model (LEM) and detailed hydrogen/air chemistry. Results are presented for the influence of initial temperature inhomogeneities on the heat release rate and the relative importance of diffusion and chemical reactions. The predicted heat release rates are compared with heat release rates of Chen et al. and Hawkes et al. obtained by two-dimensional Direct Numerical Simulations (DNS). Using the definition of Chen et al. for the displacement speed of the H2 mass fraction tracked at the location of maximum heat release, and a comparison of budget terms, different combustion modes including ignition front propagation and deflagration waves are identified and the results are compared to the DNS data. The LEM approach shows qualitatively and quantitatively reasonable agreement with the DNS data over the whole range of investigated temperature fluctuations. The results presented in this work suggest that LEM is a potential candidate as a sub-model for CFD calculations of HCCI engines.
Author: | Michael Oevermann, Heiko Schmidt, Alan R. Kerstein |
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Document Type: | ZIB-Report |
Tag: | HCCI; Linear-Eddy Modell; Selbstzündung; Turbulenz HCCI; Linear-Eddy Model; autoignition; thermal explosion; turbulence |
MSC-Classification: | 76-XX FLUID MECHANICS (For general continuum mechanics, see 74Axx, or other parts of 74-XX) / 76Fxx Turbulence [See also 37-XX, 60Gxx, 60Jxx] / 76F25 Turbulent transport, mixing |
80-XX CLASSICAL THERMODYNAMICS, HEAT TRANSFER (For thermodynamics of solids, see 74A15) / 80Axx Thermodynamics and heat transfer / 80A25 Combustion | |
80-XX CLASSICAL THERMODYNAMICS, HEAT TRANSFER (For thermodynamics of solids, see 74A15) / 80Axx Thermodynamics and heat transfer / 80A32 Chemically reacting flows [see also 92C45, 92E20] | |
Date of first Publication: | 2008/01/29 |
Series (Serial Number): | ZIB-Report (08-05) |
ISSN: | 1438-0064 |
ZIB-Reportnumber: | 08-05 |