Design and optimization of the nozzle geometry of a high pressure hydrogen injector

Abstract

[EN] Hydrogen, a clean-burning fuel with one of the highest energy densities, is seen as the future fuel, not only for automobile applications but also to generate electricity. The use of hydrogen to power internal combustion engines has yielded promising results. Due to the lack of carbon in hydrogen, no carbon compounds are emitted into the atmosphere by these engines. Air pollution will be reduced, leaving just nitrogen oxides as source of harmful emissions. Moreover, injection techniques are closely linked to abnormal combustion in spark-ignition engines such as knocking, pre-ignition or backfiring. Port fuel injection issues such as pre-ignition or backfiring can be solved with direct injection. The goal of this thesis is to optimize the geometry of the nozzle of a single cylinder highpressure direct injection hydrogen engine. Parameters were varied over a wide range of values to implement the ideal nozzle. Angles ! and " together with the diameter of the injector hole were among those considered. The model was implemented in CATIA and then imported into CONVERGE to prepare the nozzle for a Computational Fluid Dynamics simulation. A single hole nozzle and a two-hole nozzle were the two models that were created. Lambda, cylinder pressure, heat release rate or mass flow rate were some of the values studied. Over the course of this work, it was examined how the influence of the parameters affected the values indicated above.

[ES] El objetivo de este trabajo es optimizar un motor de investigación monocilíndrico para su uso con hidrógeno bajo inyección directa a alta presión. Se están investigando diversas estrategias de inyección y geometrías de inyectores con respecto a su efecto en el proceso de combustión. Para mantener bajo el esfuerzo experimental, se utilizan simulaciones 3D-CFD de la combustión para estimar los efectos de los diseños de toberas modificadas. En este trabajo, se van a construir e investigar diferentes geometrías de toberas mediante simulación. Posteriormente, el modelo del inyector se integrará en un modelo de combustión para estimar los efectos sobre la combustión además de la influencia sobre la formación de la mezcla.