Flame visualizations using electrical capacitance tomography (ECT)

Stray-immune circuits are available that will measure very small floating capacitances at high speed These circuits have facilitated the development of Electrical Capacitance Tomography (ECT), which uses fixed, robust metal plates as sensors, arranged non-intrusively around the periphery of the volume of interest. The phenomenon of flame ionization is well understood, with general agreement that the concentration of all the major ions maximize at the flame front. There is also strong experimental evidence to suggest that the presence of carbon particles (and their precursors) results in a large increase in the charge carrying capacity of the flame. This paper reports some initial results from using ECT to visualize the position, size, composition and movement in flames in open and closed combustion chambers.