Kinetics of Ignition and Combustion in the Al–CH₄–O₂ System

Abstract

The extensive analysis of chain mechanism development in the Al–CH4–O2 mixture is conducted on the basis of a novel kinetic model taking into account the latest theoretical data on rate constants of elementary reactions. The physical properties of Al-containing compounds, needed for the calculation of their transport coefficients, are estimated with the use of a quantum-chemical approach. It has been shown that the addition of a small amount of aluminum nanoparticles to the methane–oxygen mixture substantially accelerates the chain mechanism and results in the decrease of the ignition delay and the increase of the laminar flame speed. The higher the concentration of Al in the mixture, the greater the effect of combustion enhancement. The principal reactions responsible for this effect are indicated.

Review of Chemical Reactivity of Singlet Oxygen with Organic Fuels and Contaminants

“…Applying the excitation power of singlet oxygen emerged as one of the most attractive approaches in combustion enhancement in internal combustion (IC) engines [188,197–201] . This implies that when singlet oxygen is presented in combustion systems, such as H 2 −O 2, [194,202–204] CH 4 −O 2, [193,205,206] and CO−H 2 −O 2 [192] it intensifies the ignition and enhances the decomposition kinetic. For example, in the CO−H 2 −O 2 system, singlet oxygen showed an ability to convert selectively and rapidly CO into CO 2 at 900 K [192] .…”

Experimental study of combustion of composite fuel comprising n-decane and aluminum nanoparticles

“…In the recent study, addressed the analysis of chain mechanism development in the Al-CH 4 -O 2 mixture [40], on the basis of calculation with the developed detailed kinetic model it was revealed that the addition of nano-Al to methane results in the acceleration of methane oxidation. In that paper, the intensification of chain process in the CH 4 -air mixture due to adding small amount of Al nanoparticles to methane was explained by the appearance of the novel channels of chain mechanism development.…”

“…At the first stage, Al atoms interact with O 2 with the formation of AlO and O in the course of reaction path R1. This reaction occurs with rather high rate (its rate constant k R1 = 2.31 × 10 13 × T 0.17 cm 3 /mole/s [40]) even at low temperature, because it has zero activation barrier. Further, atomic oxygen reacts with n-decane in the reaction of chain propagation n-C 10 In the case of pure n-decane oxidation, at low temperatures T ≤ 1000 K, the chain mechanism is initiated by the following [42] n-C 10 H 22 + O 2 = C 10 H 21 + HO 2 .…”

Aluminum Combustion under Different Condition: A Review

“…Aluminum is a reactive material that can be used as fuel added for propellant, ethanol, CH4 and solid-fuel [1][2][3][4]. Aluminum also has a high energy density and is also low in cost [5].…”