flame holder

File:TurbofanWithAfterburnerP232b.jpg

File:US Navy 030201-N-9605S-028 Aviation Machinist's Mate 2nd Class Lloyd Keeling, from Exeter, Calif., inspects the flame holder of the afterburner to an F-A-18E.jpg

File:F-100 B M SERIES FLAMEHOLDER OF P072 - NARA - 17473614.jpg

A flame holder is a component of a jet engine used as an ignitor to help maintain continual combustion.https://www.researchgate.net/figure/An-aircraft-jet-engine_fig2_4205809 In a scramjet engine the residence time of the fuel is very low and complete penetration of the fuel into the flow will not occur.{{cite web | url=https://patents.google.com/patent/US7954328B2/en | title=Flame holder for minimizing combustor screech }} To avoid these conditions flame holders are used.{{cite web | url=https://www.wikimotors.org/what-is-a-flame-holder.htm | title=What is a Flame Holder? (With picture) }}

All continuous-combustion jet engines require a flame holder.{{cite book | chapter-url=https://link.springer.com/chapter/10.1007/978-3-030-66881-5_6 | doi=10.1007/978-3-030-66881-5_6 | chapter=Flameholder Design Guidelines | title=Subsonic Combustion Ramjet Design | series=SpringerBriefs in Applied Sciences and Technology | date=2021 | last1=Ingenito | first1=Antonella | pages=47–74 | isbn=978-3-030-66880-8 }} A flame holder creates a low-speed eddy in the engine to prevent the flame from being blown out.{{cite web | url=http://www.topedge.com/panels/aircraft/sites/mats/f14-detail-engine.htm | title=HOME OF M.A.T.S. - the most comprehensive Grumman F-14 Reference Work - by Torsten Anft! }} The design of the flame holder is an issue of balance between a stable eddy and drag.{{cite web | url=https://blog.partsbase.com/afterburner-components/ | title=Understanding the Components of an Afterburner | Blog: Aircraft News & PartsBase Aviation Information | date=16 July 2023 }}

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 to a V-gutter helps reduce drag without reducing effectiveness.https://www.ijser.org/researchpaper/Temperature-Prediction-and-Validation-of-V-Gutter-for-an-Aeroengine-Afterburner.pdf 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.{{Cite journal | last1 = Matkowsky | first1 = B. J. | last2 = Olagunju | first2 = D. O. | year = 1981 | title = Pulsations in a Burner-Stabilized Premixed Plane Flame | journal = SIAM Journal on Applied Mathematics | volume = 40 | number = 3 | pages = 551–562 | jstor = 2101350 | doi=10.1137/0140046}} See p. 552.