Growth of Electrically Charged Soot Particles in Flames

A part of the soot particles in fuel-rich hydrocarbon flames carry an electric charge. Charges of both signs occur on soot particles in the same flame. Through a molecular beam sampling system, charged soot particles and smaller ions have been drawn from low pressure flames of acetylene and benzene and analyzed in an electrostatic mass filter and a deflection system. The development of particle mass, number density and the volume fraction of charged and neutral soot is reported for these flames under different burning conditions. The volume fraction of charged soot in acetylene flames increases with temperature while there are no large charged soot particles at all in benzene flames. The role of charged species in the mechanism of soot formation and the process of charging is discussed in terms of a chemiionization mechanism. This article is from 'Combustion Problems in Turbine Engines Held at the Propulsion and Energetics Panel Symposium (62nd) Cesme (Turkey) on 3-6 October 1983,' AD-A140 700, p19-1 - 19-10.