1. Gas jet flow characteristic of high-pressure methane pulsed injection of single-hole cylindrical nozzle.
- Author
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Lei, Yan, Liu, Jiaxing, Qiu, Tao, Li, Yunqiang, Wang, Yupeng, Wan, Bo, and Liu, Xianwu
- Subjects
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JETS (Fluid dynamics) , *GAS flow , *NOZZLES , *MACH number , *SPRAY nozzles , *METHANE , *NATURAL gas - Abstract
• An optical test rig is built to observe the high-pressure methane gas direct injection in a CVB. • A 3D numerical model of high-pressure methane injection in a CVB is verified by the test data. • The methane jet penetration has a two-stage behavior induced by the dynamic inner flow inside the nozzle. • The methane jet tip penetration and the penetration speed become saturated as the injection pressure rises high enough. • This jet saturation behavior is caused by inner flow saturation of Mach number and gas velocity inside the nozzle. For a direct injection natural gas engine, the fuel jets into the cylinder in cycles, and this gas pulsed injection process causes crucial effects on the combustion. This study presents an experimental investigation on the methane direct injection. An optical test rig is designed to observe the high-pressure methane jet into a constant-volume bomb (CVB), and a numerical model is built to analyze the gas flow. The methane jet has a two-stage feature. The gas jet characteristic parameters (the tip penetration, penetration speed, jet cone cover area) change rapidly in dynamic stage I, and become stable in stable stage II. The dynamic process inside the nozzle induces this two-stage gas jet flow. The inner methane flow experiences a time delay from the inlet to the outlet, and the gas jet undergoes the same time delay to maintain stable. Furthermore, the injection pressure has great effects on the gas jet. As the injection pressure rises high enough, the gas jet saturation behavior occurs, and it is caused by inner flow saturation of Mach number, Reynolds number and gas velocity inside the nozzle. It is not necessary to increase injection pressure as high as possible for improving the gas jet characteristics. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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