Self-ignition of hydrocarbon–hydrogen–air mixtures

Three-dimensional numerical simulation of a continuously rotating detonation in the annular combustion chamber with a wide gap and separate delivery of fuel and oxidizer

“…where P is the pressure and [S] denotes the concentration of species S. Equation (2) was obtained by ¦tting the dependences of the induction period on the pressure and temperature obtained for reaction (1) to those calculated within the framework of an extensively tested detailed kinetic mechanism of hydrogen oxidation [21,22]. Note that the heat of reaction (1) was modi¦ed to make the calculated ChapmanJouguet detonation velocity D CJ for the stoichiometric hydrogenair mixture be consistent with its thermodynamic value (D CJ ≈ 1970 m/s).…”

Kinetic and dynamic analysis of hydrogen-enrichment mixtures in combustor systems – A review paper

“…However, a higher hydrogen fuel fraction is required to auto-ignite the flame under the temperature regime. Further, the addition of hydrogen to hydrocarbon/air plays the role of a self-ignition inhibitor at temperature lower than 1050 K. This is mainly caused by the formation of fewer active species, like HO radicals, which in turn hinder the chain-branching processes [6]. By adding hydrogen and maintaining the condition of mild combustion, the critical auto-ignition with tri-brachial flames still contains the linear relation between the flow time and the square of the adiabatic ignition delay time [26] (as shown in Eq.…”

“…However, the benefits of using pure hydrogen as a source of fuel seem to be limited due to some difficulties, particularly on storage issues. These difficulties are relating to its low density (0.08 kg/m at 300 K and 1 atm), wider range of fammability limits (from 4% to 75%), higher laminar flame velocity (2.3 m/s at normal conditions) and very low ignition energy (0.02 mJ) [6] and this drawback properties would make pure hydrogen becoming a second alternative energy sources Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/rser compared to pure hydrocarbons. From the previous study, hydrocarbon-hydrogen fuel mixtures would be the best substitution to overcome these drawbacks (local flame extinction, combustion instabilities, lower power output, etc.…”

“…Moreover, for the diffusion of combustion, hydrogen-enrichments can suppress the formation of soot particles [72,90] and reduce ignition delay [6,26,53,91].…”

The Effect of Hydrogen Addition on the Combustion Characteristics of RP-3 Kerosene/Air Premixed Flames

“…Nevertheless, CO emissions become quite difficult to control under lean conditions. Furthermore, it has been found that a strong correlation exists between NO x and CO emissions: NO x emissions reduction will increase CO emissions [2]. This trade-off problem between NO x and CO emissions can only be solved by adding new degrees of freedom (e.g., hydrogen) to the system.…”