A flame holder is a component of a jet engine used as an ignitor to help maintain continual combustion. [1] 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. [2] To avoid these conditions flame holders are used. [3]
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All continuous-combustion jet engines require a flame holder. [4] A flame holder creates a low-speed eddy in the engine to prevent the flame from being blown out. [5] The design of the flame holder is an issue of balance between a stable eddy and drag. [6]
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. [7] 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. [8]
