Effects of Geometry on Passive Pre-Chamber Combustion Characteristics

Abstract
Towards a fundamental understanding of the ignition characteristics of pre-chamber (PC) combustion engines, computational fluid dynamics (CFD) simulations were conducted using CONVERGE. To assist the initial design of the KAUST pre-chamber engine experiments, the primary focus of the present study was to assess the impact of design parameters such as throat diameter, nozzle diameter, and nozzle length. The well-stirred reactor combustion model coupled with a methane oxidation mechanism reduced from GRI 3.0 was used. A homogeneous charge of methane and air with λ = 1.3 on both the PC and main chamber (MC) was assumed. The geometrical parameters were shown to affect the pre-chamber combustion characteristics, such as pressure build-up, radical formation, and heat release as well as the composition of the jets penetrating and igniting the main chamber charge. In addition, the backflow of species pushed inside the pre-chamber due to the flow reversal (FR) event was analyzed. It was found that the narrow throat type of pre-chamber is strongly influenced by the throat diameter, but weakly influence by nozzle length. A flow reversal pattern was observed, which promoted the accumulation of intermediate species in the PC, leading to a secondary heat release.

Citation
Silva, M., Sanal, S., Hlaing, P., Cenker, E., Johansson, B., & Im, H. G. (2020). Effects of Geometry on Passive Pre-Chamber Combustion Characteristics. SAE Technical Paper Series. doi:10.4271/2020-01-0821

Acknowledgements
The paper is based upon work supported by Saudi Aramco Research and Development Center FUELCOM3 program under Master Research Agreement Number 6600024505/01. FUELCOM (Fuel Combustion for Advanced Engines) is a collaborative research undertaking between Saudi Aramco and KAUST intended to address the fundamental aspects of hydrocarbon fuel combustion in engines, and develop fuel/engine design tools suitable for advanced combustion modes. The computational simulations utilized the Shaheen supercomputer at KAUST Supercomputing Laboratory. The authors thank Convergent Science Inc. for providing the CONVERGE license.

Publisher
SAE International

Conference/Event Name
SAE 2020 World Congress Experience, WCX 2020

DOI
10.4271/2020-01-0821

Additional Links
https://www.sae.org/content/2020-01-0821/

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