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A Numerical Study on the Effects of the Orifice Geometry between Pre- and Main Chamber for a Natural Gas Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 08, 2017 by SAE International in United States
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The spark-ignited pre-chamber stratified combustion system is one of the most effective ways of expanding lean-burn ability and improving the performance of a natural gas engine. For these pre-chamber engines, the geometrical structure of orifices between the pre- and main chamber plays a significant role on the gas flow and flame propagation behaviors. The present study aims to investigate the effects of orifice number and diameter on combustion characteristics of a Shengdong T190 natural gas engine through CFD simulation. Various geometrical structures for the pre-chamber orifices were designed, offering variations in the number of orifices (4 to 8), and in the diameter of orifices (1.6mm to 2.9mm). A non-dimensional parameter β was employed to characterize the relative flow area of the orifices in the design.
CFD simulations of combustion processes for these designs were carried out using a simplified chemical reaction kinetic mechanism for methane. Results show that, for a constant β value, the 6-orifice design can obtain the optimal results, while the design of excessive orifices leads to insufficient radial propagation of flames in the main chamber, and the design of less orifices leads to insufficient circumferential flames propagations in the main chamber. For a 6-orifice pre-chamber, a design of larger diameters leads to slower penetrating for the flame jets and insufficient radial flames propagations in the main chamber, and a design of relatively smaller orifice diameters leads to insufficient circumferential flames propagations in the main chamber. The optimal orifice diameter obtained in this study is 2mm, corresponding to a β value of 0.3. Consequently, it was confirmed that the optimal design is the 6-orifice with diameter of 2mm for the pre-chamber. This design achieves a 35.0% increase of indicated thermal efficiency and a 78.0% reduction of NOx emission compared to the prototype engine.
CitationWang, M., Leng, X., He, Z., Wei, S. et al., "A Numerical Study on the Effects of the Orifice Geometry between Pre- and Main Chamber for a Natural Gas Engine," SAE Technical Paper 2017-01-2195, 2017, https://doi.org/10.4271/2017-01-2195.
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- Arkadiusz J, Wojciech T, Arkadiusz K, et al. Numerical simulation of two-stage combustion in SI engine with prechamber[J]. Applied Mathematical Modelling, 2013, 37: 2961-2982.
- Shah, A., Tunestal, P., and Johansson, B., "Effect of Relative Mixture Strength on Performance of Divided Chamber ‘Avalanche Activated Combustion’ Ignition Technique in a Heavy Duty Natural Gas Engine," SAE Technical Paper 2014-01-1327, 2014, doi:10.4271/2014-01-1327.
- Douailler, B., Ravet, F., Delpech, V., Soleri, D. et al., "Direct Injection of CNG on High Compression Ratio Spark Ignition Engine: Numerical and Experimental Investigation," SAE Technical Paper 2011-01-0923, 2011, doi:10.4271/2011-01-0923.
- Shah, A., Tunestal, P., and Johansson, B., "CFD Simulations of Pre-chamber Jets’ Mixing Characteristics in a Heavy Duty Natural Gas Engine," SAE Technical Paper 2015-01-1890, 2015, doi:10.4271/2015-01-1890.
- Toulson, E., Schock, H., and Attard, W., "A Review of Pre-Chamber Initiated Jet Ignition Combustion Systems," SAE Technical Paper 2010-01-2263, 2010, doi:10.4271/2010-01-2263.
- Boeckhoff N, Mögele H. Improvement & new applications of the MAN 51/60 gas engine for marine & power plant[C]//CIMAC Paper NO.:294,2013.
- Watanabe K, Goto K, Hashimoto H, et al. Update on Wärtsilä 4-stroke gas product development[C]//CIMAC Paper NO.:406, 2013.
- Christian T, Andreas B, Nikolaus S, et al. GE’s all new J920 gas engine- a smart accretion of two-stage turbocharging, ultra lean combustion concept and intelligent controls [C]//CIMAC Paper NO.:289,2013.
- Jan GAO, De-ming JIANG, Zuo-hua HUANG, et al. Numerical study on spray and mixture stratified combustion in a direct injection gasoline engine[J]. Transactions of CSICE, 2005, 23(4):296-306.
- Zesty E, Nagy T, Simmie J M. Reduction of a detailed kinetic model for the ignition of methane/propane mixtures at gas turbine conditions using simulation error minimization methods [J]. Combustion and Flame, 2011, 158:1469-1476.
- Shu-sheng Li, Shu-zhan Bai, Xiao-wei Xing, et al. Influence of pre-chamber parameters on combustion process in large natural gas engine [J]. Chinese Internal Combustion Engine Engineering, 2012, 33(6):72-76. (in Chinese)
- Kirkpatrick Allan, Kim Giheon, Olsen Daniel. CFD modeling of the performance of a pre-chamber for use in a large bore natural gas engine. ASME ICES 2005-1049.
- Heywood, J.B., “Internal Combustion Engine Fundamentals”, International edition, McGraw-Hill, New York, 1988.
- Watson, H., Milkins, E., Goldsworth, L., "Optimizing the spark ignition pre-chamber geometry including spark plug configuration for minimum NOx emissions and maximum efficiency," SAE Paper 82013, 1982.