Acta Physico-Chimica Sinica ›› 2019, Vol. 35 ›› Issue (11): 1241-1247.doi: 10.3866/PKU.WHXB201812031

• Article • Previous Articles     Next Articles

Chemical Kinetic Model for the Combustion of the Green Propellant of the Nitrous Oxide Fuel Blend

Dong ZHENG1,*(),Pengfei XIONG2,Beijing ZHONG3   

  1. 1 School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
    2 Airbreathing Hypersonic Technology Research Center, China Aerodynamics Research and Development Center, Mianyang 621000, Sichuan Province, P. R. China
    3 School of Aerospace Engineering, Tsinghua University, Beijing 100084, P. R. China
  • Received:2018-12-18 Accepted:2019-01-01 Published:2019-02-21
  • Contact: Dong ZHENG E-mail:zhengd11@yeah.net
  • Supported by:
    the National Natural Science Foundation of China(51606212);Fundamental Research Funds for the Central Universities, China(2682017CX035)

Abstract:

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 sub-mechanism. 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.

Key words: Nitrous, Small hydrocarbons, Chemical mechanism, Ignition delay time, Green propellant

MSC2000: 

  • O643