Explicit formulation of the reactivity of hydrogen, methane and decane

Autoignition dynamics of DME/air and EtOH/air homogeneous mixtures

“…Since the conclusions drawn with this methodology are limited to the neighborhood of the specific operating conditions considered, the analysis has to be assessed or even repeated for any significantly different set of operating conditions. Although these mathematical tools are still successfully employed [7][8][9], their usefulness is questionable when they have to deal with the very large chemical kinetics mechanisms that have lately been of interest. The development of algorithmic methodologies for the construction of reduced models facilitated considerably the analysis of autoignition processes.…”

A new method for systematic 1-step chemistry reduction applied to hydrocarbon combustion

“…This strategy avoids the need to define a virtual species with ad-hoc thermodynamic parameters [4,10] . Next, let us introduce a general reaction rate for the global reaction (21) as…”

“…As duly noted in the literature, chemical timescales associated with ignition are different from those of premixed flame propagation and tackling both phenomena with a single step is non-trivial [8,27,28] . It is well understood that the ignition process can be well represented by chained reactions building up a radical pool, which eventually will trigger heat-releasing reactions [21,22,29,30] . The exponential character arises from the fact that the reaction rate is proportional to the radical pool concentration, leading to an exponential evolution of radical concentrations [22] .…”

“…Regarding the second objective, several options can be found in the literature recovers the kinetic properties. Starting from the detailed chemistry elementary rates, partial-equilibrium and quasisteady-state approximations are used in fully analytically derived mechanisms [9,20] , while more systematic methods study the kinetic source term Jacobian to obtain the main chemical time-scales (see, e.g., [2,3,21] ). Very short mechanisms (1-2 steps) tend to resort directly to carefully fitted rates to recover the desired set of kinetic properties [4,10] .…”

“…The method relies only on fitting nine parameters based on detailed chemistry calculations or experimental data, but does not require any tabulation. Section 4 presents a new passive scalar approach based on an eigenvalue study of the Jacobian similar to [2,3,21,22] . The passive scalar serves as an efficiency function in the singlestep chemistry and allows to recover ignition characteristics, in addition to partially-premixed phenomena.…”