Based on an externally heated high-temperature and high-pressure constant volume combustion chamber system, an optical diagnostic test on the combustion process of diesel-ignited premixed natural gas was carried out using the natural luminescence method. The effects of different natural gas energy substitution rate(ESR), diesel injection pressure pinj and diesel injection mass minj on the ignition and combustion characteristics were studied. The results show that an increase in ESR leads to an increase in the equivalence ratio of methane to air. Since the specific heat of methane is greater than that of air, the increase in ESR has a promoting effect on diesel ignition. At the same time, the decrease in oxygen makes the increase in ESR, having an inhibitory effect. When the diesel injection mass is small, the increase of ESR has a stronger inhibitory effect on ignition than its promoting effect. When the diesel injection mass is large, the opposite result is presented. With the increase of ESR, the proportion of concentrated soot is increased, but under the diesel injection pressure of 100MPa and the ESR of 94%, there is a stage with a high proportion of concentrated soot. When the diesel injection pressure is higher than 100MPa, the enhancement effect of injection pressure on combustion heat release weakens, and there is no significant increase in the amount of ignited methane. Under the injection strategy of minj=10mg, pinj=80MPa, the ignition delay exhibits a strong linear relationship with the ESR range of 94%—96%.
| 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 |