Behavior of a small diffusion flame as an electrically active component in a high-voltage circuit

Active control of combustion is challenging because there are few actuators with sufficient power to overcome the effects associated with the significant energy release associated with flames. The control leverage afforded by adjusting the fuel stream has so far been the most effective for this purpose. Naturally occurring flame ions allow an alternative control option via external electric fields, and this mechanism has been investigated, in experimental analysis of small non-premixed flame acted on by a high-voltage grid. During the course of these studies, the voltage–current characteristics of air–methane flames has been identified. This article describes how electric fields acting on flame ions affect the local convective environment and produce a very characteristic electrical behavior that can be analyzed as part of an electrical circuit for control in order to produce a desired flame response, using the ion production as a sensor for overall reaction intensity and a fairly simple PID control algorithm to effect the desired flame response.