Probability density function treatment of turbulence/chemistry interactions during the ignition of a temperature-stratified mixture for application to HCCI engine modeling
- 246 Hesse Hall, Mailstop 1740, Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740 (United States)
- Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740 (United States)
- School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, NSW 2052 (Australia)
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-9051 (United States)
Homogeneous charge compression ignition (HCCI) engine technology promises to reduce NO{sub x} and soot emissions while achieving high thermal efficiency. Temperature and mixture stratification are regarded as effective means of controlling the start of combustion and reducing the abrupt pressure rise at high loads. Probability density function methods are currently being pursued as a viable approach to modeling the effects of turbulent mixing and mixture stratification on HCCI ignition. In this paper we present an assessment of the merits of three widely used mixing models in reproducing the moments of reactive scalars during the ignition of a lean hydrogen/air mixture ({phi}=0.1, p=41atm, and T=1070 K) under increasing temperature stratification and subject to decaying turbulence. The results from the solution of the evolution equation for a spatially homogeneous joint PDF of the reactive scalars are compared with available direct numerical simulation (DNS) data [E.R. Hawkes, R. Sankaran, P.P. Pebay, J.H. Chen, Combust. Flame 145 (1-2) (2006) 145-159]. The mixing models are found able to quantitatively reproduce the time history of the heat release rate, first and second moments of temperature, and hydroxyl radical mass fraction from the DNS results. Most importantly, the dependence of the heat release rate on the extent of the initial temperature stratification in the charge is also well captured. (author)
- OSTI ID:
- 21125483
- Journal Information:
- Combustion and Flame, Vol. 155, Issue 4; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PROBABILITY DENSITY FUNCTIONS
IGNITION
MIXING
SIMULATION
STRATIFICATION
HEAT
AIR
COMBUSTION
DIESEL ENGINES
HYDROGEN
TURBULENCE
HYDROXYL RADICALS
TEMPERATURE RANGE 1000-4000 K
SCALARS
MATHEMATICAL SOLUTIONS
TIME DEPENDENCE
COMPRESSION
MASS
COMPARATIVE EVALUATIONS
HCCI
Mixing models