An example system can include a combustor of a jet turbine engine, a radio-frequency power source, a plasma-distributing structure, and a resonator having a first concentrator. The combustor can include one or more fins protruding into a combustion zone and can be configured to guide combustion of fuel along a flame path defined by the fin(s). The resonator can be configured to provide a plasma corona when excited by the power source. The plasma-distributing structure can be arranged within the combustor and proximate to the plasma corona, and can include a second concentrator. When the resonator is excited, the plasma corona can be provided proximate to the first concentrator. Further, when the plasma corona is provided proximate to the first concentrator and the plasma-distributing structure is at a predetermined voltage, an additional plasma corona can be established proximate to the second concentrator and at least partly within the flame path.

An example system can include a combustion chamber of a jet engine, one or more radio-frequency power sources, a plurality of resonators, and a fuel conduit. The plurality of resonators can be electromagnetically coupled to the one or more radio-frequency power sources and each have a respective resonant wavelength. Further, each resonator can include (i) a respective first conductor, (ii) a respective second conductor, and (iii) a respective dielectric between the first conductor and the second conductor, and can be configured to provide at least one of a plasma corona or electromagnetic waves. The fuel conduit can be configured to couple to a fuel source and have a fuel outlet for expelling fuel into a combustion zone of the combustion chamber. A portion of the fuel conduit is disposed within the first conductor of a given resonator of the plurality of resonators.

An example system and corresponding method can include a combustion chamber of jet engine, a radio-frequency power source, and a resonator. The combustion chamber can include a liner defining a combustion zone, and include a fuel inlet configured to introduce fuel into the combustion zone. The resonator can have a resonant wavelength and include: a first conductor, a second conductor, a dielectric, and an electrode coupled to the first conductor. The resonator can be configured such that, when the resonator is excited by the radio-frequency power source with a signal having a wavelength proximate to an odd-integer multiple of one-quarter () of the resonant wavelength, the resonator provides a plasma corona in the combustion zone. The controller can be configured to cause the radio-frequency power source to excite the resonator with the signal so as to provide the plasma corona.

A system includes a radio-frequency power source, a resonator, a fuel outlet, and an afterburner. The afterburner includes a duct that defines a channel, and can receive gas from a turbine of a jet engine into the channel and output a gas resulting from combusting fuel within the channel. The resonator can be configured to be electromagnetically coupled to the power source and has a resonant wavelength. The resonator includes first and second conductors, a dielectric between the first and second conductors, and an electrode coupled to the first conductor and disposed within the afterburner. The fuel outlet outputs fuel into the channel for mixing with the gas from the turbine. The resonator, when excited by the power source with a signal having a wavelength proximate to an odd-integer multiple of one-quarter of the resonant wavelength, provides electromagnetic waves and/or a plasma corona proximate to a concentrator of the electrode.

An example system and corresponding method can include a combustion chamber of a power-generation gas turbine, a radio-frequency power source, and a resonator. The combustion chamber can include a liner defining a combustion zone, and include a fuel inlet configured to introduce fuel into the combustion zone. The resonator can have a resonant wavelength and include: a first conductor, a second conductor, a dielectric, and an electrode coupled to the first conductor. The resonator can be configured such that, when the resonator is excited by the radio-frequency power source with a signal having a wavelength proximate to an odd-integer multiple of one-quarter of the resonant wavelength, the resonator provides a plasma corona in the combustion zone. The controller can be configured to cause the radio-frequency power source to excite the resonator with the signal so as to provide the plasma corona.

An example system and corresponding method includes a power-generation turbine combustor and a resonator. The combustor includes (i) a combustion zone, (ii) one or more fuel inlets for introducing fuel into the combustion zone for combustion, and (iii) one or more fins protruding into the combustion zone and configured to guide combustion of the fuel along a flame path. The resonator can have a resonant wavelength and can provide a plasma corona in the combustion zone when excited with a signal having a wavelength proximate to an odd-integer multiple of one-quarter () of the resonant wavelength. A radio-frequency power source can excite the resonator with the signal so as to provide the plasma corona in the combustion zone and cause combustion of the fuel along the flame path.

Example implementations relate to jet engines that include resonator-based diagnostics. An example implementation includes a jet engine. The jet engine includes a combustion chamber configured to house a combustion event of a fuel mixture. The jet engine also includes a resonator having a characteristic impedance and a resonant wavelength. The resonator includes a first conductor and a second conductor separated from one another by an interstitial space that is exposed to an environment of the combustion chamber. Further, the jet engine includes a controller communicatively coupled to the resonator and configured to perform operations. The operations include determining a characteristic of the resonator selected from the group consisting of the characteristic impedance and the resonant wavelength. The operations also include, based on the determined characteristic, determining a parameter of the combustion chamber.

An ignition and combustion assist system and method comprising a plasma igniter and electronic driver unit for use with gas turbine engines operating under low air densities, reduced voltage conditions and overall pressure ratios of 3:1 to 7:1. The plasma igniter has an inner chamber housing a centrally positioned and electrically isolated electrode attached to an electrical lead, driver unit, and AC or DC power supply. The electrode features a corner positioned near an outlet end of the igniter, where a plasma arc ignites a fuel-air mixture creating a flame extending into a primary burn region of a combustor of the gas turbine. The driver unit is in two embodiments and configured with low-cost microsecond voltage wave time periods or energy-efficient nano-second pulses. The method uses the plasma igniter and the electronic driver units described herein separately with other components or together.

A plasma injection module includes a fuel receiving end, a discharge end opposite the fuel receiving end, and an axial fluid pathway extending between the fuel receiving end and the discharge end. An insulator assembly defines a first portion of the axial fluid pathway proximate to the fuel receiving end. An injection tube assembly having a permanent magnet is positioned downstream of the insulator. A voltage input connection is arranged downstream of the insulator assembly and upstream of the injection tube assembly. The voltage input connection secures a voltage source to the injection tube to form a plasma filament within and adjacent to the axial fluid pathway. During operation a permanent magnet produces a magnetic field that interacts with the plasma filament to rotate the plasma filament and increase an area of ignition between the plasma filament and the combustible material at the discharge end.

An ignition and combustion assist system and method comprising a plasma igniter and electronic driver unit for use with gas turbine engines operating under low air densities, reduced voltage conditions and overall pressure ratios of 3:1 to 7:1. The plasma igniter has an inner chamber housing a centrally positioned and electrically isolated electrode attached to an electrical lead, driver unit, and AC or DC power supply. The electrode features a corner positioned near an outlet end of the igniter, where a plasma arc ignites a fuel-air mixture creating a flame extending into a primary burn region of a combustor of the gas turbine. The driver unit is in two embodiments and configured with low-cost microsecond voltage wave time periods or energy-efficient nano-second pulses. The method uses the plasma igniter and the electronic driver units described herein separately with other components or together.