Self-Exited Oscillation in a Combustion Chamber Driven by Phase Change in the Liquid Fuel Feed System

Abstract

A new mechanism for the generation of a self-exited oscillation of combustion in a generic combustion chamber typical for aeroengine combustors is described. The cause of the oscillation is the phase change from liquid to vapour which happens when the preheat temperature of the air flowing through the burner exceeds the boiling temperature at the operating pressure and the fuel flow is so low that heat transfer to the liquid fuel causes evaporation within the fuel channels of the burner. Liquid fuel and vapour alternatively enter the airstream of the burner. This leads to an unstable situation for the flame. Measurements of chemiluminescence and liquid fuel show nearly complete extinction and re-ignition for the limit cycle. Prevention of the oscillation is possible by better thermal management of the fuel path.

Numerical Study on the Self-Pulsation Characteristics of LOX/GH2 Swirl Coaxial Injector

“…With a larger gas-liquid ratio, self-pulsation occurs, which is found to determine the flow structures inside the spray cone and to generate, shed, and dissipate vortices periodically. Except for the flow rates of each propellant, scholars [23] have found that the self-pulsation can be motivated by the phase change from liquid to vapor which happens when the preheat temperature of the gas flowing through the burner exceeds the boiling temperature at the operating pressure. However, this mechanism of the self-pulsation due to the propellant phase change caused by the temperature change is unclear.…”