Large-eddy simulation of methane direct injection using the full injector geometry

FUEL

卷:290

Article

Yosri, M. R.¹  Ho, J. Z.¹  Meulemans, M.¹  Talei, M.¹  Gordon, R. L.¹  Brear, M. J.¹  Cosby, D.²  Lacey, J. S.³ 

[1] Univ Melbourne, Dept Mech Engn, Parkville, Vic 3010, Australia

[2] Continental, Newport News, VA USA

[3] Katholieke Univ Leuven, Dept Mech Engn, B-3001 Leuven, Belgium

关键词: Large-Eddy Simulation (LES);    Constant Volume Chamber (CVC);    Schlieren;    Under-expanded gaseous jet;    Direct Injection (DI);   

DOI  :  10.1016/j.fuel.2020.120019

来源: Elsevier

【 摘 要 】

Understanding the mixing process of under-expanded gaseous-fuel jets from an outward opening injector is essential for developing Direct Injection (DI) internal combustion engines. This paper presents a Large-Eddy Simulation (LES) study of the DI of methane into a Constant Volume Chamber (CVC), considering the full, internal geometry of a prototype injector. Four cases at conditions relevant to Compressed Natural Gas (CNG) DI engines are investigated, with methane as a surrogate for CNG. A new post-processing method permits the 3D LES field to be projected into a 2D density gradient field that can be compared to a schlieren image. The LES results are then validated against high-speed, schlieren imaging experiments, demonstrating that the simulations are able to reproduce experimental trends. Three main regions of the external flow are observed: a recirculation zone just downstream of the injector tip, a stagnation zone and a far-mixing zone. The location of the stagnation zone increases as the CVC pressure decreases, consistent with a theory presented in the literature. The modelling of the full internal geometry of the injector leads to a determination of the injector pressure losses. Once the pressure loss within the injector is considered, a short version of the injector can reasonably represent the full injector for prediction of the external flow.

【 授权许可】

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