A Numerical Study of the Influence of Different Operating Conditions on the Combustion Development in an Automotive-Size Diesel Engine 2015-01-1852
In this paper, numerical simulations of an automotive-size optical diesel engine have been conducted employing the Reynolds-Averaged Navier-Stokes (RANS) equations with the standard k-ε turbulence model and a reduced n-heptane chemical mechanism implemented in OpenFOAM. The current paper builds on a previous work where the model has been validated for the same engine using optical diagnostic data. The present study investigates numerically the influence of different operating conditions - relevant for modern diesel engines - on the mixture formation development under non-reactive conditions as well as low- and high-temperature ignition behaviour and flame evolution in the presence of strong jet-wall interactions typically encountered in automotive-size diesel engines. Also, emissions of CO and unburned hydrocarbons (UHC) are considered. This has been systematically studied by varying four different engine parameters: 1) Engine swirl: zero, nominal (baseline) and double of the swirl; 2) Fuel injection pressure: 1000 and 1600 (baseline) bar; 3) Intake pressure: 1 (baseline) and 2 bar; 4) Ambient oxygen mole fraction: 21 (baseline) and 15%.
The swirl was found to have a minor influence on the inert fuel spatial distribution. On the other hand, the swirl has a large impact on the high-temperature rather than on the low-temperature ignition and this effect is more pronounced for the low fuel injection pressure case where high-temperature combustion on the up-swirl side is suppressed for the high swirl case. This effect is not observed for the 1600 bar injection pressure case and it can potentially have a strong impact on the unburned hydrocarbons (UHC) emissions.
Citation: Pasunurthi, S., Hawkes, E., Bolla, M., Le, M. et al., "A Numerical Study of the Influence of Different Operating Conditions on the Combustion Development in an Automotive-Size Diesel Engine," SAE Technical Paper 2015-01-1852, 2015, https://doi.org/10.4271/2015-01-1852. Download Citation
Author(s):
Shyam S. Pasunurthi, Evatt R. Hawkes, Michele Bolla, Minh K. Le, Sanghoon Kook, Tommaso Lucchini, Gianluca D'Errico
Affiliated:
University of New South Wales, Dipartimento di Energia, Politecnico di Milano
Pages: 9
Event:
JSAE/SAE 2015 International Powertrains, Fuels & Lubricants Meeting
ISSN:
0148-7191
e-ISSN:
2688-3627
Related Topics:
Diesel / compression ignition engines
Fuel injection
Combustion and combustion processes
Pressure
Hydrocarbons
Wind tunnel tests
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