|
| Large Eddy Simulation of Stratified Lean Combustion in a Direct Injection Hydrogen Engine |
| DOI：10.13949/j.cnki.nrjgc.2025.02.001 |
| Key Words:hydrogen jet simplified injector model stratified lean combustion direct injection hydrogen engine large eddy simulation（LES） |
|
| Hits: 488 |
| Download times: 280 |
| Abstract:To investigate the formation process of the stratified lean mixture in a direct injection hydrogen engine and its influence on the combustion process， three-dimensional computational fluid dynamics （CFD） numerical simulation was carried out on the hydrogen jet， mixing process， and combustion process of two hydrogen injectors of different sizes under the same engine operating conditions based on large eddy simulation （LES） method. An injector simplification scheme was adopted to reduce the calculation time and maintain high accuracy. The effectiveness of the injector simplification scheme was verified by constant-volume vessel and engine simulations respectively. In the constant-volume vessel simulation， the root mean square errors of the jet penetrations of the two hydrogen injectors under different vessel back pressures compared to the test data were within 5.0%. In the engine simulation， engine cylinder pressures in the combustion stage with the two hydrogen injectors were basically consistent with the test data. The engine simulation results show that there is no substantial difference in the basic characteristics of the engine mixture formation process of the two injectors， but the engine with the small-flow injector has a better mixture stratification effect before ignition and smaller combustion cycle variation. The end of injection （EOI） significantly affects the stability of hydrogen-stratified lean combustion. Excessive delay of EOI will cause the mixture around the spark plug to be too lean， resulting in slow ignition or even misfire. |
| View Full Text View/Add Comment Download reader |