Flame holder
Encyclopedia
A flame holder is a component of a jet engine
designed to help maintain continual combustion
.
All continuous-combustion jet engines require a flame holder. A flame holder creates a low-speed eddy
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
.
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.
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
designed to help maintain continual combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
.
All continuous-combustion jet engines require a flame holder. A flame holder creates a low-speed eddy
Eddy (fluid dynamics)
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid flows past an obstacle. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object...
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 (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
.
The simplest design, often used in amateur projects, is the can-type flame holder, which consists of a can
Tin can
A tin can, tin , steel can, or a can, is a sealed container for the distribution or storage of goods, composed of thin metal. Many cans require opening by cutting the "end" open; others have removable covers. Cans hold diverse contents: foods, beverages, oil, chemicals, etc."Tin" cans are made...
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
Base bleed is a system used on some artillery shells to increase their range, typically by about 30%.Most of the drag on an artillery shell comes from the nose of the shell, as it pushes the air out of its way at supersonic speeds. Shaping the shell properly can reduce this greatly. However,...
to a V-gutter helps reduce drag without reducing effectiveness.