Basically, there are three gas turbine combustor types (combustion chambers): 1) can (or tubular), 2) annular, and 3) can-annular type. Thus, their classification is made according to geometric characteristics. Burner is an informal word for combustion chamber.
1) A can type combustor consists of a cylindrical liner mounted concentrically inside a cylindrical casing. The majority of the early jet engines were fitted with tubular chambers as there usually were between 7 and 16 of them per engine. Nevertheless, for most aircraft applications, the tubular system is too long and heavy, resulting in an engine of a large frontal area and high drag.
2) In the annular type, an annular liner is mounted concentrically inside an annular casing, providing the most efficient use of volumetric space. It is a good form of chamber, because its “clean” aerodynamic layout results in a compact unit of lower pressure loss than other chamber designs. However, one negative outcome of annular system excellent aerodynamic features is that a slight variation of the velocity profile of the inlet air can produce an important change in the temperature distribution of the outlet gases.
3) In the can-annular type combustor, a group of cylindrical liners is set inside a single annular casing. This kind of chamber is an attempt to combine the compactness of the annular combustor with the best features of the tubular system. Compared with the annular design, the tuboannular chamber has an important advantage in that much useful chamber development can be carried out with very modest air supplies, using a small segment of the total chamber containing one or more liners.
Below, a schematic diagram of a typical can-annular type combustion chamber assembly.
