Abstract

This paper discusses the fl ame ionization effect on the combustion processes in gaseous suspensions of the dispersed fuels. It is shown that the two-phase fl ame ionization<br />affects almost all the processes of the fuel conversion – kinetics of the dispersed fuel combustion, processes of the interphase heat and mass transfer, processes of the nucleation and coagulation in the fl ame, formation of nanoscale products of the metal particles combustion. It is shown that the electrostatic interaction between the charged nanoparticles and ions or polar molecules in the gaseous phase leads to the appearance of molecular “pumps” that can signifi cantly change the kinetics of the heterogeneous chemical reactions and the heat exchange between particles and gas. The infl uence of the thermal ionization of the fl ame on the nucleation mechanism<br />and rate in gas-dispersed systems is discussed. The possibility of a barrier-free homogenous and heterogeneous nucleation in the dusty fl ame of metallic particles is shown. The effect of electrostatic and polarizing interactions of ions and molecules<br />on the kinetics of the ternary gas-phase reactions is considered. The infl uence of the monodisperse aerosol ionization degree on the kinetics of its coagulation is analyzed. It is concluded that electrostatic interaction between the particles strongly affects the inhibition of the coagulation process in gas-phase combustion products and the possibility of very fast (explosive) charged particle coagulation of monodisperse aerosols. The possibility of the targeted size of metal oxides nanoparticles control, controlled ionizing of dusty fl ames and the role of ion particle entrainment, the dependency of their size of the fl ame ionization degree are discussed. Some effects arising in complex plasma of condensed combustion products under its own electric fi elds in fl ames, also when the burning dust is entrained into a constant electric field and their practical applications for diagnosis are considered.

Highlights

  • The idea of using plasmas to improve fuel burning has a long history and the last two decades is actively developing

  • The hot plasma is generated in electric arc AC or DC and leads to a strong heating of the ambient in the discharge channel, which significantly reduces the energy of electrons required for the flame ionization

  • The electrons temperature is close to the gas temperature and the gas phase of plasma is close to equilibrium

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Summary

Introduction

The idea of using plasmas to improve fuel burning has a long history and the last two decades is actively developing. This became a relevant scientific and technical direction named Plasma Assisted Ignition and Combustion. The majority of data of plasma impact on fuel conversion processes are obtained for a gas flame. Recent researches in this area are reviewed in [1]. The plasma impact on a dispersed fuel ignition and combustion processes in the oxidizing gas is less studied. To intensify the burning of coals and the flame stabilization

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