Numerical Study on Internal Flow and Cavitation Characteristics of GDI Injectors for Different Nozzle Orifice Geometries

Chaoqun Hu, Zhijun Wu (), Alessandro Ferrari (), Meng Ji, Jun Deng and Oscar Vento
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Chaoqun Hu: School of Automotive Studies, Tongji University, Shanghai 201800, China
Zhijun Wu: School of Automotive Studies, Tongji University, Shanghai 201800, China
Alessandro Ferrari: Energy Department, Politecnico di Torino, 10129 Turin, Italy
Meng Ji: School of Automotive Studies, Tongji University, Shanghai 201800, China
Jun Deng: School of Automotive Studies, Tongji University, Shanghai 201800, China
Oscar Vento: Energy Department, Politecnico di Torino, 10129 Turin, Italy

Energies, 2024, vol. 17, issue 16, 1-21

Abstract: The geometry of an orifice is a major determinant of nozzle internal flow and cavitation, which directly govern spray atomization and consequently affect combustion and fuel economy in internal combustion engines. In this study, simulation models of the nozzle at different angles between the normal and the injection hole inlet cross-section and the injection hole axis, as well as with different injection hole cone angles (a positive angle between the injection hole axis and its walls implies a divergent hole), were investigated by means of a previously developed numerical model that was validated based on experimental data from X-ray image technology. The results indicate that as the angle between the normal and the injection hole inlet cross-section and the injection hole axis increases, the cavitation asymmetry within the injection hole intensifies, accompanied by a decrease in the gas volume fraction. On one side of the injection hole, the hydraulic flip width expands, while, on the other side of the injection hole, the flow state gradually changes from hydraulic flip to super-cavitation flow, transitional cavitation and fully reattached flow. The divergent orifice layout intensifies cavitation, and the higher the positive injection hole cone angle, the bigger the hydraulic flip width. The convergent layout of the injection hole suppresses cavitation, and cavitation inside the nozzle disappears completely when the injection hole cone angle is less than −10°.

Keywords: GDI; nozzle geometry; internal flow; cavitation; CFD (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2024
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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