Flashback is one undesirable condition that can occur in state of the art combustion or burner systems, such as gas turbine combustion systems having one or more fuel nozzles configured to provide a premixing of fuel and air in a premixing zone located upstream of a burning zone (main combustion zone). The flashback condition generally occurs when a flame travels upstream from the main burning zone into the premixing zone, which is not intended to sustain combustion reactions. As a consequence, serious damage may occur to the combustion system, potentially resulting in a catastrophic malfunction of the system and a concomitant substantial financial loss.
The use of ion-sensing detectors (e.g., U.S. Pat. No. 6,429,020) and other devices, such as thermocouples and fiber optics, to detect flashback is well known. However, up to the present invention, flashback detection techniques (including those described in the foregoing patent) have commonly required the detection device to be at the premixing zone. That is, such techniques have typically required the detection device to be positioned downstream of one or more fuel injectors. This positioning requirement of the flashback detection device may entail a fairly complex integration into the fuel nozzle and/or installation arrangements subject to reduced reliability and/or burdensome access for reparability or servicing, once the combustion system is operationally deployed. Accordingly, for some combustor geometries it may be desirable to provide a flashback detection arrangement in a combustion system, such as a gas turbine, that is not subject to the foregoing drawbacks.