Details
| Original language | English |
|---|---|
| Pages (from-to) | 2778-2787 |
| Number of pages | 10 |
| Journal | Combustion and Flame |
| Volume | 162 |
| Issue number | 7 |
| Publication status | Published - 16 May 2015 |
Abstract
To describe the premixed combustion of natural gas in internal combustion engines, the flamelet approach is often assumed to be appropriate. It postulates a thin flame front which is wrinkled by turbulence but locally spreads like a laminar flame. Numerous correlations for the macroscopic turbulent flame speed to the local laminar flame speed exist. In this study seven correlations are validated at engine conditions, i.e., at high pressure (up to 7.0MPa) and high turbulence (turbulent Reynolds number up to 4.4·104), with the help of measurements from a single cylinder research gas engine. The stoichiometry, the exhaust gas recirculation rate, and the engine speed are varied. Simulations of the detailed reaction kinetics with the diffusive species and energy transport are performed to calculate the laminar flame speed. The flame propagation is described by a zonal cylinder model on the basis of the measured in-cylinder pressure traces, to determine the turbulent flame speed with respect to the thermal expansion of the reacting gas. Additionally, Computational Fluid Dynamics (CFD) simulations of the in-cylinder charge motion are performed to describe the turbulent flow field. It is found that four flame speed correlations including a pressure-dependent term predict flame speed ratios in quantitative accordance to the measurements. This is noteworthy, as these correlations are mostly developed for lower turbulence and at considerable lower pressure. It supports the hypothesis that flamelet-like combustion is still found above the Klimov-Williams criterion.
Keywords
- Charge dilution, High pressure, Laminar flame speed, Methane-air, Single cylinder gas engine, Turbulent flame speed
ASJC Scopus subject areas
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In: Combustion and Flame, Vol. 162, No. 7, 16.05.2015, p. 2778-2787.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Validation of turbulent flame speed models for methane-air-mixtures at high pressure gas engine conditions
AU - Ratzke, Ansgar
AU - Schöffler, Tobias
AU - Kuppa, Kalyan
AU - Dinkelacker, Friedrich
PY - 2015/5/16
Y1 - 2015/5/16
N2 - To describe the premixed combustion of natural gas in internal combustion engines, the flamelet approach is often assumed to be appropriate. It postulates a thin flame front which is wrinkled by turbulence but locally spreads like a laminar flame. Numerous correlations for the macroscopic turbulent flame speed to the local laminar flame speed exist. In this study seven correlations are validated at engine conditions, i.e., at high pressure (up to 7.0MPa) and high turbulence (turbulent Reynolds number up to 4.4·104), with the help of measurements from a single cylinder research gas engine. The stoichiometry, the exhaust gas recirculation rate, and the engine speed are varied. Simulations of the detailed reaction kinetics with the diffusive species and energy transport are performed to calculate the laminar flame speed. The flame propagation is described by a zonal cylinder model on the basis of the measured in-cylinder pressure traces, to determine the turbulent flame speed with respect to the thermal expansion of the reacting gas. Additionally, Computational Fluid Dynamics (CFD) simulations of the in-cylinder charge motion are performed to describe the turbulent flow field. It is found that four flame speed correlations including a pressure-dependent term predict flame speed ratios in quantitative accordance to the measurements. This is noteworthy, as these correlations are mostly developed for lower turbulence and at considerable lower pressure. It supports the hypothesis that flamelet-like combustion is still found above the Klimov-Williams criterion.
AB - To describe the premixed combustion of natural gas in internal combustion engines, the flamelet approach is often assumed to be appropriate. It postulates a thin flame front which is wrinkled by turbulence but locally spreads like a laminar flame. Numerous correlations for the macroscopic turbulent flame speed to the local laminar flame speed exist. In this study seven correlations are validated at engine conditions, i.e., at high pressure (up to 7.0MPa) and high turbulence (turbulent Reynolds number up to 4.4·104), with the help of measurements from a single cylinder research gas engine. The stoichiometry, the exhaust gas recirculation rate, and the engine speed are varied. Simulations of the detailed reaction kinetics with the diffusive species and energy transport are performed to calculate the laminar flame speed. The flame propagation is described by a zonal cylinder model on the basis of the measured in-cylinder pressure traces, to determine the turbulent flame speed with respect to the thermal expansion of the reacting gas. Additionally, Computational Fluid Dynamics (CFD) simulations of the in-cylinder charge motion are performed to describe the turbulent flow field. It is found that four flame speed correlations including a pressure-dependent term predict flame speed ratios in quantitative accordance to the measurements. This is noteworthy, as these correlations are mostly developed for lower turbulence and at considerable lower pressure. It supports the hypothesis that flamelet-like combustion is still found above the Klimov-Williams criterion.
KW - Charge dilution
KW - High pressure
KW - Laminar flame speed
KW - Methane-air
KW - Single cylinder gas engine
KW - Turbulent flame speed
UR - http://www.scopus.com/inward/record.url?scp=84929960590&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2015.04.011
DO - 10.1016/j.combustflame.2015.04.011
M3 - Article
AN - SCOPUS:84929960590
VL - 162
SP - 2778
EP - 2787
JO - Combustion and Flame
JF - Combustion and Flame
SN - 0010-2180
IS - 7
ER -