Oscillatory combustion is a source of abnormal combustion noise which can occur in virtually anytype of combustion system ranging from furnaces for residential heating systems with combustionchambers measuring only 2 ft. (0.6 m) to blast furnace stoves with combustion chambers standing100 ft. (30 m) tall. Typically, self-excited oscillations will only occur under some operatingconditions. In small devices, such as furnaces, they may occur only briefly during start-up;but even this is totally unacceptable because of the extreme annoyance of the radiated noise.In large systems, such as blast furnace stoves, there is not only annoyance, but sound pressureof sufficient magnitude to destroy the brickwork and cause physiological damage.

This paper presents the theoretical basis for preventing combustion oscillations. A companionpaper (Ref. 1) provides some experimental data,and test techniques for this purpose.