This paper reports the validation of a three-dimensional numerical simulation of the in-cylinder processes during gas-exchange, injection, and compression in a direct-injection, hydrogen-fueled internal combustion engine. Computational results from the commercial code Fluent are compared to experimental data acquired by laser-based measurements in a corresponding optically accessible engine. The simulation includes the intake-port geometry as well as the injection event with its supersonic hydrogen jet. The cylinder geometry is typical of passenger-car sized spark-ignited engines. Gaseous hydrogen is injected from a high-pressure injector with a single-hole nozzle. Numerically and experimentally determined flow fields in the vertical, central symmetry plane are compared for a series of crank angles during the compression stroke, with and without fuel injection. With hydrogen injection, the fuel mole-fraction in the same data plane is included in the comparison as well. The results show that the simulation predicts the flow field without injection reasonably well, with increasing numerical-experimental disagreement towards the end of the compression stroke. The injection event completely disrupts the intake-induced flow, and the simulation predicts the post-injection velocity fields much better than the flow without injection at the same crank-angles. The two-dimensional tumble ratio is evaluated to quantify the coherent barrel motion of the charge. Without fuel injection, the simulation significantly over-predicts tumble during most of the compression stroke, but with injection, the numerical and experimental tumble ratio track each other closely. The evolution of hydrogen mole-fraction during the compression stroke shows conflicting trends. Jet penetration and jet-wall interaction are well captured, while fuel dispersion appears under-predicted. Possible causes of this latter discrepancy are discussed.
- Internal Combustion Engine Division
CFD and Optical Investigations of Fluid Dynamics and Mixture Formation in a DI-H2ICE
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Scarcelli, R, Wallner, T, Obermair, H, Salazar, VM, & Kaiser, SA. "CFD and Optical Investigations of Fluid Dynamics and Mixture Formation in a DI-H2ICE." Proceedings of the ASME 2010 Internal Combustion Engine Division Fall Technical Conference. ASME 2010 Internal Combustion Engine Division Fall Technical Conference. San Antonio, Texas, USA. September 12–15, 2010. pp. 175-188. ASME. https://doi.org/10.1115/ICEF2010-35084
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