Characterization and mechanism of soot formation in C 4 H 10 combustion with H 2-NH 3 addition

This study employed extinction method and thermophoretic sampling techniques to explore the characteristics of soot formation in C 4 H 10 combustion with H 2 -NH 3 addition. The impact of H 2 -NH 3 addition on the formation of PAHs and soot was analyzed using ReaxFF MD. It is found that the adding H 2 -NH 3 leads to a decrease of fv max , with the inhibitory effect on soot formation being stronger for i-C 4 H 10 compared to n-C 4 H 10 . Adding H 2 -NH 3 inhibits the growth of soot particles, reducing the peak average primary particle diameter of soot particles. The chemical effect of H 2 promotes soot formation in n-C 4 H 10 combustion but inhibits it in i-C 4 H 10 combustion. However, both NH 3 and H 2 -NH 3 addition chemically inhibit soot formation in C 4 H 10 combustion. The A 1 pathways reveal that the C -C bond cleavage in n-C 4 H 10 is significantly stronger than C -H bond cleavage, while it is exactly the opposite in i-C 4 H 10 . Adding H 2 promotes the reaction equilibrium CH 3 + H 2 4-* CH 4 + H towards the forward reaction, facilitating C -C bond cleavage and A 1 formation in n-C 4 H 10 but inhibiting C -H bond cleavage and A 1 formation in i-C 4 H 10 . However, adding NH 3 results in the cleavage of N -H bonds, producing a large amount of H. This shifts the reaction equilibrium CH 3 + H 2 4-* CH 4 + H towards the reverse reaction, ultimately suppressing A 1 formation.