Electric field modulation effect and mechanism on n-alkanes fuel pyrolysis: A ReaxFF MD and DFT study

To promote the fuel utilization efficiency in the aviation and space transport, the electric field was selected as an efficiency method to modify the fuel pyrolysis rate. This work investigated the surrogate fuel component n-alkane (n-pentane, n-heptane and n-decane) pyrolysis process under the electric field. The three n-alkanes py-rolysis rate and reaction pathway were analyzed. And the reaction mechanism under the electric field was discussed by the bond cracking potential energy (PES), system thermal motion and energy. The molecular dy-namics results showed the n-alkanes pyrolysis was modulated by the electric field strength, which promotion in weak electric field and inhibition in strong field. The species transformation net was complicated and selective while the conversion flux was reduced by the strong field. The field improved the molecule polarization and deformation to result in the edged carbon bond and H bond dissociation with lower energy barriers. Analyzing the molecular motion and system energy, the intermolecular distance was elongated, and interaction energy was reduced, which caused to the decrease of collision frequency under the field. The contribution of electric field to the single molecule decomposition and inhibition molecules motion worked together on the global n-alkane pyrolysis. This work supplied a theory support to the promoting fuel utilization using the electric energy.

Automated summary

In this study, the electric field was used to modify the pyrolysis rate of n-alkane fuels. The pyrolysis process and mechanism of three n-alkanes (n-pentane, n-heptane, and n-decane) under the electric field were investigated. It was found that the electric field strength had an impact on the pyrolysis rate, with weak electric fields promoting pyrolysis and strong electric fields inhibiting pyrolysis. The electric field also induced molecular polarization and deformation, resulting in lower energy barriers for carbon bond and hydrogen bond dissociation. The increased intermolecular distance and reduced interaction energy caused a decrease in collision frequency. The contribution of the electric field to both individual molecule decomposition and inhibition of molecular motion played a role in the overall pyrolysis of n-alkanes. This work provides theoretical support for promoting fuel utilization using electric energy.