A flame holder is a

component Component may refer to: In engineering, science, and technology Generic systems *System components, an entity with discrete structure, such as an assembly or software module, within a system considered at a particular level of analysis * Lumped e ...

of a

jet engine A jet engine is a type of reaction engine, discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition may include Rocket engine, rocket, Pump-jet, water jet, and ...

used as an

ignitor Ignitor is the Italian name for a proposed tokamak device, developed by ENEA. The project was abandoned in 2022. History Started in 1977 by Prof. Bruno Coppi at MIT, Ignitor based on the 1970s Alcator machine at MIT which pioneered the high ...

to help maintain continual

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

. In a

scramjet A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forcefully b ...

engine the residence time of the fuel is very low and complete penetration of the fuel into the flow will not occur. To avoid these conditions flame holders are used. All continuous-combustion jet engines require a flame holder. A flame holder creates a low-speed

eddy Eddy may refer to: * Eddy (surname), surname used by descendants of a number of English, Irish and Scottish families * Eddy (given name), male given name * Eddy (fluid dynamics), the swirling of a fluid and the reverse current created when the fl ...

in the engine to prevent the flame from being blown out. The design of the flame holder is an issue of balance between a stable eddy and

drag Drag or The Drag may refer to: Places * Drag, Norway, a village in Tysfjord municipality, Nordland, Norway * ''Drág'', the Hungarian name for Dragu Commune in Sălaj County, Romania * Drag (Austin, Texas), the portion of Guadalupe Street a ...

. The simplest design, often used in amateur projects, is the can-type flame holder, which consists of a can covered in small holes. Much more effective is the H-gutter flame holder, which is shaped like a letter H with a curve facing and opposing the flow of air. Even more effective, however, is the V-gutter flame holder, which is shaped like a V with the point in the direction facing the flow of air. Some studies have suggested that adding a small amount of

base bleed Base bleed or base burn (BB) is a system used on some artillery shells to increase range, typically by about 20%–35%. It expels gas into the low-pressure area behind the shell to reduce Drag (physics), base drag (but does not produce thrust ...

to a V-gutter helps reduce drag without reducing effectiveness. The most effective of the flame holders are the step type flame holder and the strut type flame holder. The first mathematical model of a flame holder was proposed in 1953. See p. 552.

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Jet engines {{Engine-aircraft-stub

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