基于预燃室湍流射流点火氨燃料着火燃烧过程研究

In order to investigate the ignition and combustion characteristics of ammonia under turbulent jet ignition (TJI) mode, in this work, a three-dimensional numerical model of the constant volume combustion bomb (CVCB) with a TJI system was built in the numerical simulation software CONVERGE. And the ignition and combustion of ammonia was studied under TJI mode fueled with hydrogen in the pre-chamber. The results showed that, impacted by the intake process of the main combustion chamber and pre-chamber combustion after ignition, the flow between main combustion chamber and pre-chamber cane be divided into four stages. The pressure in the pre-chamber increases after the ignition and combustion of pre-chamber mixture, and a high-speed jet from the pre-chamber towards the main combustion chamber forms causing by the pre-chamber flame entrained the unburned mixture and combustion products. At spark timing, under the combined action of gas flow between the main combustion chamber and pre-chamber and hydrogen injection, the pre-chamber can be divided into three zones: over-rich mixture zone, homogeneous mixture zone and lean-mixture zone. Moreover, the overall combustion process can be divided into three stages: cold jet stage, jet flame ignition stage, and fast combustion stage in the main combustion chamber.