Effect of structural parameters of active pre-chamber on ammonia/hydrogen premixed combustion process: A numerical investigation
Zhe Kang, Da Peng, Luo Jing, Yang Lv, Lan Li
Abstract
The development of zero-carbon fuels is of great significance for reducing carbon emissions. Using an ammonia/hydrogen mixture as fuel, the combustion in engine through an active pre-chamber has a good effect on reducing carbon emissions. Moreover, the utilization of active pre-chamber is able to achieve rapid combustion speed, therefore leading to higher overall thermal efficiency. In order to realize an optimized combustion process , it is essential to investigate effects of the structural parameters of active pre-chamber on combustion process. Therefore, in this paper, an active pre-chamber combustion model was established based on a mass-produced gasoline engine, the mixture of ammonia and hydrogen was used as fuel, 8 different pre-chamber structure schemes were proposed, variations such as the angle and number of nozzle holes and the volume ratio of the pre-chamber to engine clearance volume were considered to investigate their influences. The results indicate that scheme 8, with a 60° nozzle angle, 6 holes, 1.6 mm aperture and 3.6 % volume ratio, is the optimal pre-chamber structure proposed in this study. Under this scheme, numerical calculations show an optimum thermal efficiency of 47.93 %. This study also revealed the interaction mechanism between structural parameters of active pre-chamber and the combustion process of ammonia/hydrogen mixture, which is significantly important for optimizing combustion processes and engine performance, and provides research references for the industrial utilization of ammonia-hydrogen combustion engines in passenger vehicles.