Unsteady flamelet modeling for N2H4/N2O4 flame accompanied by hypergolic ignition and thermal decomposition
Unsteady flamelet modeling for N2H4/N2O4 flame accompanied by hypergolic ignition and thermal decomposition
复制标题
伴随自燃和热分解的 N2H4/N2O4 火焰的非稳态火焰模型
DOI：
10.1016/j.jaecs.2020.100022
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发表时间：
2021
影响因子：
--
通讯作者：
Kurose R.
中科院分区：
文献类型：
--
作者：
Konishi K.;Kai R.;Kurose R.
通过对N2H4/NTO气态喷流火焰和NTO气流中N2H4喷射火焰的二维数值模拟，研究了火焰面方法在N2H4/NTO(N2H4)/N2O(NTO，N2O4)自燃和热分解燃烧过程中的适用性。对于气体喷流火焰，采用非定常火焰面/进程变量(UFPV)方法进行了数值模拟。另一方面，对于喷射火焰，提出了一种非绝热非定常火焰面/进程变量(NAUFPV)方法，该方法结合了UFPV方法和非绝热火焰/进程变量(NAFPV)方法。通过与直接求解详细化学反应的精确方法得到的结果进行比较，考察了这些方法和其他一些现有火焰面方法的有效性。结果表明，UFPV和NAUFPV方法分别显著改善了对N2H4/NTO气态和喷雾燃烧行为的预测，包括着火过程、火焰升起高度、温度分布和化学物种浓度分布。这表明UFPV方法成功地捕捉到了燃料的自分解火焰，NAUFPV方法还可以考虑液滴蒸发的热损失效应。
In this study, the applicability of the flamelet approach to numerical simulations of hydrazine (N 2 H 4)/nitrogen tetroxide (NTO, N 2 O 4) combustion, in which hypergolic ignition and thermal decomposition occur, is investigated in terms of two-dimensional numerical simulations of two types of N 2 H 4/NTO jet flames, namely, the gaseous N 2 H 4/NTO jet flame and the N 2 H 4 spray jet flame in the gaseous NTO stream. In case of the gaseous jet flame, the numerical simulation is performed employing the unsteady flamelet/progress variable (UFPV) approach. In case of the spray jet flame, on the other hand, a non-adiabatic unsteady flamelet/progress variable (NAUFPV) approach, which combines the UFPV approach and the non-adiabatic flamelet/progress variable (NAFPV) approach, is proposed. The validity of these and some other existing flamelet approaches is investigated by comparison with the results obtained using the exact approach, in which detailed chemical reactions are directly solved. The results show that the UFPV and NAUFPV approaches drastically improve predictions of the N 2 H 4/NTO gaseous and spray combustion behavior, respectively, including the ignition process, the flame lift-off height, and the distributions of temperature and chemical species concentrations. This indicates that self-decomposition flame of fuel is successfully captured by the UFPV approach, and that the NAUFPV approach can additionally take into account the heat loss effect due to evaporation of droplets.