Exploring the effect of fluid dynamics and kinetic mechanisms on n-heptane autoignition in transient jets
- Department of Environmental Engineering and Physics, University of Basilicata, viale dell'Ateneo Lucano 10, 85100 Potenza (Italy)
The influence of physical parameters and of flow patterns on the prediction of n-heptane ignition dynamic in transient reacting n-heptane jets, in high pressure environment under laminar conditions, has been explored by using different kinetic mechanisms. Some preliminary transient laminar flamelet computations have been performed, thus showing that the sensitivity of the ignition time to strain rate depends on the kinetic mechanism used. Therefore, the structure of the reacting jet, in particular the localization of ignition spots, is investigated. The results show that, if the initial temperature of the reacting mixture is out of the intermediate range (800-1000 K) towards lower values, the fluid dynamics has an essential role. In this case, the ignition delay time is almost insensitive to the specific kinetic mechanism adopted, conversely it is severely shortened by increasing the streamwise velocity. The burning spot is located in the core of fuel roll-up, where low values of scalar dissipation rate occur. Nevertheless, the most reactive mixture fraction conditions are well predicted by chemical kinetics, as they are in good agreement with those computed for the one-dimensional diffusion layer. When the initial temperature of fuel and air is increased in the intermediate range, ignition is strongly dependent on the kinetic mechanism used. In these cases, the choice of an accurate chemical scheme is fundamental in order to obtain reliable results. (author)
- OSTI ID:
- 21262170
- Journal Information:
- Combustion and Flame, Vol. 157, Issue 2; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HEPTANE
AUTOIGNITION
FLUID MECHANICS
PRESSURE RANGE MEGA PA 10-100
JETS
TRANSIENTS
MIXTURES
AIR
FUELS
CALCULATION METHODS
ONE-DIMENSIONAL CALCULATIONS
STRAIN RATE
TIME DELAY
DIFFUSION
TIME DEPENDENCE
FORECASTING
COMBUSTION KINETICS
SENSITIVITY
VELOCITY
CONFIGURATION
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 0273-0400 K
LAMINAR FLOW
Reacting jets