Electromagnetic fields and nanoenergetic particles in reacting flows
File(s)
Author(s)
Kritikos, Efstratios
Type
Thesis
Abstract
To increase the environmental sustainability of the transportation and energy generation sectors, new technologies must be developed. This research provides a theoretical and numerical investigation of multiphysics phenomena in reacting flows as a possible path for innovation towards more effective control of reacting flows. The main focus is on the interaction of reacting flows with electromagnetic fields and nanoenergetic particles across a range of scales. First, quantum mechanics computations of hydrocarbon oxidation reactions are performed. Results show that electric fields affect the electronic structure of the transition states, leading to catalysis or inhibition. The electron distribution is also affected by strong magnetic fields, as a consequence of the induced currents. Second, reactive molecular dynamics simulations of hydrocarbon oxidation are performed. Findings indicate that electrostatic fields affect the collision frequency and translational, rotational, and vibrational degrees of freedom of reactants and products. The Lorentz force could introduce stabilization and alignment effects. Results also highlight the impact of the used charge equilibration method on the prediction of the system's electrodynamics. Conversely, the magnetic response of hydrocarbon kinetics was negligible. Subsequently, the behaviour of metal nanoparticles, either as fuel substitutes or fuel additives, under external electric fields is analyzed. Nanoparticles act as catalysts in the dissociation process of heavy hydrocarbon and oxygen molecules. External electric fields can further increase the reactivity of the system. Moreover, the negatively charged absorbed species diffuse along the surface under the Lorentz forces, causing anisotropic chemical compositions and shell thicknesses in the nanoparticle. Lastly, to study the electromagnetic field effects in reacting flows at macroscales, a computational fluid dynamics code is developed. The numerical framework describes electromagnetic wave interactions with neutrals, ions, and electrons, considering classical electrodynamics and quantum mechanical effects. Results show that electrostatic and inhomogeneous magnetostatic fields can significantly influence the reacting flow. Additionally, for sufficiently high ion and electron concentration and mobility, time-dependent electromagnetic waves are induced. This research offers a comprehensive evaluation of multiphysics phenomena at the quantum, atomistic, and macroscopic levels, with the potential of inspiring novel technologies for the propulsion and power generation sectors.
Version
Open Access
Date Issued
2023-08
Date Awarded
2023-12
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Giusti, Andrea
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)