When injecting hydrogen gas into the intake air path and in-cylinder environment of an internal combustion engine, there is a transition from supercritical to subcritical between the injection pressure and ambient pressure. High-speed schlieren imaging technology was used to study the injection characteristics under different conditions in a constant volume combustion bomb. The results show that the penetration distance, jet surface area, and jet volume of the hydrogen jet vary with time under different conditions. However, the change in the jet cone angle after 1ms is not significant, and the difference remains within 2°. When the supercritical injection enters the supercritical environment, the interaction between the jet and surrounding gases enhances turbulence intensity, which facilitates the entrainment of more surrounding gases. An empirical formula for the jet penetration distance of the hydrogen jet was proposed, which has proved to be high accuracy. These results can be utilized to optimize the mixture formation and combustion of hydrogen internal combustion engines, providing references for hydrogen injection strategies.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |