Influence of Geometric Parameters of Pre-Chamber on Mixture Formation in Marine Ammonia/Hydrogen Engines

Pre-chamber ignition technology can address the issue of uneven in-cylinder mixture combustion in large-bore marine engines. The impact of various pre-chamber structures on the formation of the mixture and jet flames within the pre-chamber is explored. This study performed numerical simulations on a large-bore marine ammonia/hydrogen pre-chamber engine prototype, considering pre-chamber volume, throat diameter, the distance between the hydrogen injector and the spark plug, and the hydrogen injector angle. Compared with the original engine, when the pre-chamber volume is 73.4 ml, the throat diameter is 14 mm, the distance ratio is 0.92, and the hydrogen injector angle is 80 degrees. Moreover, the peak pressure in the pre-chamber increased by 23.1%, and that in the main chamber increased by 46.3%. The results indicate that the performance of the original engine is greatly enhanced by altering its fuel and pre-chamber structure.