To explore the effect of water vapor (H₂O(g)) on the formation characteristics of ultrafine particulate matter (PMs), Huangling coal char reacted in a high-temperature drop tube furnace (DTF) at 1800 K under various O₂/N₂/H₂O atmospheres, with the content of H₂O(g) varied at 0, 5%, 10%, 20% and 30% respectively. The results showed that both the number-based and mass-based particle size distributions (PSDs), the bimodal distribution of ultrafine PMs remained almost unchanged with increasing H₂O(g) content, while the peak of ultrafine PMs shifted and the magnitude of the main peak fluctuated. H₂O(g) elevated the mass fraction of ultrafine PMs with a larger particle size (D₅₀ = 0.2134 μm) and the number fraction of ultrafine PMs with a smaller particle size (D₅₀ = 0.0093 μm and D₅₀ = 0.0167 μm) significantly. With the increase of H₂O(g) content, both the number and mass of ultrafine PMs decreased first and then increased with the inflection point at 5% H₂O(g) content, indicating that lower H₂O(g) content inhibited the formation of ultrafine PMs while higher H₂O(g) content promoted its formation. Meanwhile, with the increase of H₂O(g) content, the average mass of single ultrafine particle, being higher in wet combustion atmospheres than that in dry combustion atmosphere, increased first and then decreased with the inflection point at the content of 5%. In addition, when the H₂O(g) content was 5%, the average particle size of ultrafine particle was the largest, which increased by 9.07% compared with that under dry combustion atmosphere. Finally, the influence mechanism of H₂O(g) on the formation of ultrafine PMs during char combustion was clarified.

为了探索水蒸气（H ₂ O（g））对超细颗粒物（PMs）形成特性的影响，黄陵煤焦在1800 K的高温下降管式炉（DTF）中在各种O ₂ /下进行了反应。在N ₂ / H ₂ O气氛中，H ₂ O（g）的含量分别在0、5％，10％，20％和30％之间变化。结果表明，随着H ₂ O（g）含量的增加，基于数量和基于质量的粒径分布（PSDs），超细颗粒物的双峰分布几乎保持不变，而超细颗粒物的峰发生了变化，且峰尺寸发生了变化。主峰波动。高₂O（克）升高超细PM的质量分数具有较大粒度（d ₅₀  = 0.2134μm）与极细的PM的具有较小粒径的数量级分（d ₅₀  = 0.0093微米和d ₅₀  = 0.0167微米）显著。随着H ₂ O（g）含量的增加，超细颗粒物的数量和质量都先下降，然后随着拐点在5％H ₂ O（g）的增加而增加，这表明较低的H ₂ O（g）含量抑制了超细颗粒物的形成，而更高的H ₂ O（g）含量促进了其形成。同时，随着H ₂的增加O（g）含量，即超细颗粒的平均质量，在湿燃烧气氛中比在干燃烧气氛中要高，然后在拐点为5％时先增加后降低。另外，当H ₂ O（g）的含量为5％时，超细颗粒的平均粒径最大，与干燥燃烧气氛下相比，增加了9.07％。最后，阐明了焦炭燃烧过程中H ₂ O（g）对超细颗粒物形成的影响机理。