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In order to meet high-performance propulsion system requirements for aerospace technology and severe future restrictions on hydrazine use, research on non-toxic, high-performance, and low-cost propulsion technology is urgently needed. The N2O-C2 hydrocarbon monopropellant NOFBX (Nitrous Oxide Fuel Blend) provides significant benefits for meeting these criteria and has become a focus of increased research in recent years. In this study, a chemical kinetic model for NOFBX combustion that integrates the reduced C2 sub-mechanism, the N2O sub-mechanism in the literature, and the N2O/CH species reaction mechanism has been developed. The present mechanism consists of 52 species and 325 elementary reactions. For better predictions of ignition and combustion characteristics, the kinetic parameters of the sensitive reactions with comparatively high rate constant uncertainties have been revised. The present model has been validated against published experimental data, including flow reactor results on N2O/H2O/N2 mixture decomposition, shock tube ignition delay times on N2O/C2 hydrocarbons diluted with N2 or Ar mixtures, heat flux of flat flame laminar flame speeds on N2O/C2H2 diluted with N2 mixtures, and Bunsen flame laminar flame speeds on N2O/C2H4 diluted with N2 mixtures. Additionally, this study compares the new model to other published small hydrocarbon fuel kinetic models with a NOx submechanism. The experimental validations show that the present model accurately captures the nitrous oxide decomposition process and precisely predicts N2O, O2, NO, and NO2 vital species concentration distributions. For all N2O-C2 hydrocarbon fuel systems (ethane-, ethylene-, and acetylene-nitrous oxide), the ignition delay times predicted by the present model are in good agreement with the experimental data. Furthermore, at a wider range of initial temperatures (1100-1700 K), initial pressures (0.1-1.6 MPa), and equivalence ratios (0.5-2.0) for the ignition delay times of ethylene-nitrous oxide, the present model exhibits improved predictions of experimental data. For the laminar flame speeds of N2O-C2H2 and N2O-C2H4 mixtures, the present model generally exhibits satisfactory predictions of the experimental data over the whole range of equivalence ratios (0.6-2.0). However, at initial pressure 0.1 MPa and equivalence ratios of 1.0-1.6 for N2O-C2H4 laminar flame speeds, the present model slightly underestimates experimental data. Considering the much higher uncertainty of the measured laminar flame speeds by the Bunsen flame method, this discrepancy is acceptable. Due to the small scale, full experimental validations and good applicability, the present model can be used to further research on multi-dimensional combustion simulation in NOFBX engine combustors.

We developed a H2 and C1-C4 heterogeneous mechanism to describe their catalytic reaction on a platinum catalyst. To verify the mechanism we carried out simulations with methane, ethane, propane, and n-butane and compared the results to the reported experimental data. The ignition and combustion (ignition or combustion of CH4, C2H6 with or without adding H2, C3H8 with or without adding H2, C4H10 with adding H2) was of interest. Good agreement was obtained and we found that H2 improved the ignition of propane and n-butane, and the combustion of ethane. However, their kinetic processes are different. Therefore, the H2 and C1-C4 heterogeneous mechanism determined in this work is reasonable with some certainty and could be used to describe the characteristics of ignition and combustion, which can be used to analyze the kinetic process.

The kinetics of the catalytic ignition processes of hydrogen/n-butane/air on Pt surface is studied to reveal the catalytic ignition mechanism. It is found that the ignition temperature of n-butane is lower when a certain amount of hydrogen is added. However, the effect of hydrogen on the catalytic ignition process and temperature of n-butane depends on the percentage of hydrogen added. When a small amount of hydrogen is added, it has a thermal effect. Adding more hydrogen gas causes it to have a chemical effect. A good fit is obtained between simulated and experimental data for the catalytic ignition temperatures. The ranges of hydrogen content with different effects are also predicted. Furthermore, this kinetic study shows that a different onset reaction of n-butane will lead to different ignition temperatures and mechanisms.

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