An igniter assembly for a gas turbine combustor includes a first electrode, a second electrode, and an insulator. The first electrode, the second electrode, and the insulator form a cavity, the second electrode forms an outlet passage extending from the cavity, a maximum cross-sectional area of the cavity is greater than a cross-sectional area of the outlet passage, and the cross-sectional area of the outlet passage is substantially constant along a longitudinal extent of the outlet passage. In addition, the first electrode and the second electrode are configured to ionize gas within the cavity in response to an electrical current applied to the first electrode or to the second electrode.

An igniter assembly for a gas turbine combustor includes a first electrode, a second electrode, and an insulator. The first electrode, the second electrode, and the insulator form a cavity, the second electrode forms an outlet passage extending from the cavity, a maximum cross-sectional area of the cavity is greater than a cross-sectional area of the outlet passage, and the cross-sectional area of the outlet passage is substantially constant along a longitudinal extent of the outlet passage. In addition, the first electrode and the second electrode are configured to ionize gas within the cavity in response to an electrical current applied to the first electrode or to the second electrode.

Lean-burn engines are important due to their ability to reduce emissions, increase fuel efficiency, and mitigate engine knock. Embodiments of a spark plug with a nanostructured electrode extend the lean flammability limit of natural gas. A nano-/micro-morphology modification is applied on a surface of the spark plug electrode to increase its surface roughness. Measurements indicate that the lean flammability limit of spark-ignited methane can be lowered by modulating the surface roughness of the spark plug electrode with nanostructures.

Lean-burn engines are important due to their ability to reduce emissions, increase fuel efficiency, and mitigate engine knock. Embodiments of a spark plug with a nanostructured electrode extend the lean flammability limit of natural gas. A nano-/micro-morphology modification is applied on a surface of the spark plug electrode to increase its surface roughness. Measurements indicate that the lean flammability limit of spark-ignited methane can be lowered by modulating the surface roughness of the spark plug electrode with nanostructures.

A pre-chamber spark plug having a shell, an insulator disposed at least partially within the shell, a center electrode disposed at least partially within the insulator, a ground electrode forming a spark gap with the center electrode, and a pre-chamber cap connected to the shell and forming a pre-chamber. The pre-chamber cap includes two or more openings that are configured so that at least one inflowing fuel-air mixture jet is directed to a pre-chamber wall gap so as to flush out or remove gas from a previous ignition cycle. The two or more openings are angled so that a first inflowing fuel-air mixture jet of a first opening does not intersect with a second inflowing fuel air-mixture jet of a second opening.

A pre-chamber spark plug having a shell, an insulator disposed at least partially within the shell, a center electrode disposed at least partially within the insulator, a ground electrode forming a spark gap with the center electrode, and a pre-chamber cap connected to the shell and forming a pre-chamber. The pre-chamber cap includes two or more openings that are configured so that at least one inflowing fuel-air mixture jet is directed to a pre-chamber wall gap so as to flush out or remove gas from a previous ignition cycle. The two or more openings are angled so that a first inflowing fuel-air mixture jet of a first opening does not intersect with a second inflowing fuel air-mixture jet of a second opening.

A spark plug has a specific direction orthogonal to an axial direction of a spark plug; the specific direction has opposing front directional side and rear directional side; the housing has a tip surface having a front end in the front side of the specific direction and a rear end in the rear side, the tip surface has a tip inclined surface inclined toward the tip end of the spark plug from the front end to the rear end of the tip surface. The tip inclined surface has a rear end in the specific direction, the insulator having a front end of the specific direction, the rear end is located to be closer to the tip end of the spark plug than the front end of the tip surface is, and to be more rearward than the front end of the insulator in the rear side of the specific direction.

A spark plug has a specific direction orthogonal to an axial direction of a spark plug; the specific direction has opposing front directional side and rear directional side; the housing has a tip surface having a front end in the front side of the specific direction and a rear end in the rear side, the tip surface has a tip inclined surface inclined toward the tip end of the spark plug from the front end to the rear end of the tip surface. The tip inclined surface has a rear end in the specific direction, the insulator having a front end of the specific direction, the rear end is located to be closer to the tip end of the spark plug than the front end of the tip surface is, and to be more rearward than the front end of the insulator in the rear side of the specific direction.

A high temperature article, for example an igniter for a combustor is presented. The igniter includes a central electrode having a discharge end, an insulator sleeve surrounding the central electrode and a tubular electrode shell surrounding the insulator sleeve. The tubular electrode shell has a forward end projecting beyond the discharge end. The tubular electrode shell includes an iron-based alloy. The igniter further includes a protective coating including alumina disposed on a surface of the forward end. A combustor of a turbine engine, including the igniter is also presented.

A high temperature article, for example an igniter for a combustor is presented. The igniter includes a central electrode having a discharge end, an insulator sleeve surrounding the central electrode and a tubular electrode shell surrounding the insulator sleeve. The tubular electrode shell has a forward end projecting beyond the discharge end. The tubular electrode shell includes an iron-based alloy. The igniter further includes a protective coating including alumina disposed on a surface of the forward end. A combustor of a turbine engine, including the igniter is also presented.