Kinetic modelling of the ignition delays in monomethylhydrazine/hydrogen/oxygen/argon gaseous mixtures

Abstract

International audienc

Contributions of Experimental Data Obtained in Concentrated Mixtures to Kinetic Studies: Application to Monomethylhydrazine Pyrolysis

“…Total rate constant predictions from RCCSD(T)/CBS//M06-2x/aug-cc-pVTZ energetics are displayed in Figure 13, as well as the branching ratios between the two reaction products. The reaction with the H atoms is the fastest, followed by the reaction with NH 2 , and finally with CH 3 , in contrast with the previous observations for CH 3 NNH for which the H abstraction with NH 2 was the slowest. Moreover, the rate constants with CH 3 NNH are significantly larger (one order of magnitude) than with CH 2 NNH 2 , suggesting that N-aminonethanimine may be a bottleneck in the thermal degradation of MMH, with a substantial residual concentration in the pyrolysis gases.…”

“…54 (CBS-QB3), and the value in braces is from Song et al 52 . 3 Scaled harmonic vibrational frequencies in cm -1 , italic values are associated to hindered internal rotors 4 Rotational constants in cm -1…”

“…However, all these interesting features are poorly characterized in terms of chemical kinetics. MMH thermal decomposition has been studied in flow reactor and shock tubes. − Detailed chemical kinetic models (DCKM) for thermal decomposition have been developed by Catoire et al, Sun et al, , and Cook et al and more recently by Li et al Those models were validated against time speciation profiles obtained in highly diluted (less than hundreds ppmv MMH) and diluted (1 up to 3 mol % MMH) mixtures in shock tubes. Theoretical calculations were applied to improve both the thermochemistry and the kinetics. ,,, The model proposed by Cook et al .…”

“…Zero point vibrational corrected energy in Hartree. Energies evaluated at the RCCSD(T)/aug-cc-pV∞Z//M06-2x-D3/aug-cc-pVTZ level of theory 2 Energy in kcal mol -1 relative to NH2NH + X 3. Scaled harmonic vibrational frequencies in cm-1 , italic values are associated to hindered internal rotors…”

The Kinetic Model Including Singlet Oxygen and Ozone in Hydrogen-Air Mixture

“…The moment of OH mole fraction reaching the maximum is considered as the criteria to judge the ignition delay time. Table 1 The ignition delay time and experiment conditions Table 1 shows the ignition delay time and the experiment conditions [8]. [9], Tayor [10], Dowdy [11], Aung [12].The initial temperature is 300 K and pressure is 1 atm.…”