Laminar Burning Velocities of Ammonia/n-Heptane/Air Mixtures at Pressures up to 1.0 MPa

The present study expanded the available database of laminar burning velocities (LBVs) of ammonia/n-heptane/air premixed flames (blending ratios of n-C₇H₁₆ up to 100%) to 1.0 MPa using a high-pressure, constant-volume combustion vessel with a pressure release tank. A relatively small-scale NH₃/n-C₇H₁₆ mechanism (named WUT-NH₃/n-C₇H₁₆) was developed via a modular and hierarchical approach. The developed mechanism was validated by the laminar burning velocities of pure NH₃ and n-C₇H₁₆, NH₃/H₂, NH₃/H₂/CO, NH₃/CH₄, NH₃/C₂H₆, NH₃/C₃H₈, and NH₃/n-C₇H₁₆. In addition, the mutual interactions between ammonia and n-heptane in premixed flames were examined. Kinetic analysis shows that n-C₇H₁₆ enhances NH₃ consumption by providing the radicals (Ḣ, ȮH, Ö, etc.). Compared to the cases for the mixture ratios of n-C₇H₁₆ of 5 and 20%, it is found that reaction pathways of NH₃ consumption: NH₃ → ṄH₂ → HNO → NO are strengthened with the increase of n-heptane addition. Overall, the effects of n-C₇H₁₆ on NH₃ in LBV at an elevated pressure and the interaction processes were identified.