Numerical Analysis of Hydrogen Peroxide Addition and Oxygen-Enriched Methane Combustion.

Methane (CH)/air lean combustion can be enhanced by increasing the concentration of the oxidizer, like oxygen (O) enrichment, or adding a strong oxidant to the reactant. Hydrogen peroxide (HO) is a strong oxidizer that yields O, steam, and appreciable heat after decomposition. This study numerically investigated and compared the effects of HO and O-enriched conditions on the adiabatic flame temperature, laminar burning velocity, flame thickness, and heat release rates of CH/air combustion using the San Diego mechanism. The result showed that in fuel-lean conditions, the adiabatic flame temperature changed from HO addition > O-enriched scenario to O-enriched scenario > HO addition with increasing α. This transition temperature was not affected by the equivalence ratio. Adding HO enhanced the laminar burning velocity of the CH/air lean combustion more than the O-enriched scenario. The thermal and chemical effects are quantified in various HO additions, and it is found that the chemical effect has a noticeable contribution to the laminar burning velocity compared with the thermal effect, especially in higher HO addition. Further, the laminar burning velocity had a quasi-linear correlation with (OH) in the flame. The maximum heat release rate was observed at lower temperatures for HO addition and higher temperatures for the O-enriched scenario. The flame thickness was significantly reduced upon adding HO. Finally, the dominant reaction to the heat release rate changed from the reaction of CH + O ↔ CHO + H in the CH/air or O-enriched scenario to the reaction of HO + OH ↔ HO + HO in the HO addition scenario.