Study of ozone-enhanced combustion in H2/CO/N2/air premixed flames by laminar burning velocity measurements and kinetic modeling

Reaction Mechanism Reduction for Ozone-Enhanced CH4/Air Combustion by a Combination of Directed Relation Graph with Error Propagation, Sensitivity Analysis and Quasi-Steady State Assumption

“…The decomposition of ozone in the pre-heating zone of the flame can initiate and accelerate chain-branching reactions [29]; as a result, the laminar flame speed is increased and the ignition delay time is decreased. Such an enhancement has already been supported both numerically and experimentally by many researchers [30][31][32][33]. Wang et al [31] and Halter et al [30] proposed a sub-mechanism that could be used in conjunction with GRI-Mech 3.0 to predict such an enhancement.…”

Investigation of the Effects of Plasma Discharges on Methane Decomposition for Combustion Enhancement of a Lean Flame

“…Table 1 shows the experimental test matrix, where S SO is the standoff distance defined as the axial distance between the HV electrode upper edge and the needle tip (see Figure 2a). All experiments were conducted by fixing both the air and the fuel flow rates at 1.12 ± 0.04 g/s and 0.0023 ± 0.0002 g/s respectively, which corresponded to the characteristic axial velocities of fuel and air flows at the burner exit of about u f = 0.074 ms −1 and u a = 2.3 ms −1 , and a global equivalence ratio [36] m is the mass flow rate, the subscripts f and a denote the fuel and the air respectively, while the subscript st refers to the stoichiometric conditions with a stoichiometric fuel-to-air ratio equal to 0.0559. It is worth observing that the local equivalence ratio differs from the global one: it varies into the flame region due to the diffusive nature of the flame, approaching unity in the proximity of the flame surface [36].…”

“…Concerning this last aspect, combustion enhancement has been observed when applying a DBD-PA for fuel/oxidizer decomposition [32,33]. Among all configurations, coaxial DBD-PAs have been widely investigated as fuel reforming reactors with promising results when applied to combustion systems [34][35][36].…”

On the role of excited species in hydrogen combustion

“…The rate constant of reaction (37) based on experimental studies [65] and supported theoretically [139,140] is adopted. Note that reaction (X16) is included in the MSU mechanism with very high rate constant (half of the rate of reaction (37)) suggested by Starik and Titova [14].…”

“…It was demonstrated [34] that due to the incompleteness of the MSU mechanism (absence of many reverse reactions) it predicts an incorrect balance between O atoms, excited and ground state oxygen in ozone flames. It should be noted, however, that ozone reactions from the MSU mechanism [25,30] excluding excited oxygen species are mostly balanced, and their implementation in the recent studies of combustion enhancement by ozone [6,[35][36][37][38][39] is justified. Yet, conclusions based on the complete set of reactions taken from the MSU mechanism by Ombrello et al [7], and by Bourig et al [26], should be treated cautiously.…”