Investigation of Flame Blow-Out in a Low Bypass Military Turbofan Engine

Abstract

Flame blow-out is a serious concern for military gas turbine engines, and maintaining a reliable and stable flame in engine throughout the mission is a great challenge. A low bypass military turbo fan engine is investigated for flame blow-out. The history of the engine and its accessories were reviewed. Flight data were analyzed to confirm the blow-out incident. Air flow passages and engine modules were examined for possible foreign object damages or internal damages and found satisfactory. Analysis of atomizer characteristics showed the shifting of spray cone angle and fuel flow rate close to the lower limits. Blockage of atomizer flow passages and liner front end flares could contribute to flame blow-out. One of the filters in the fuel line found damaged. Significant amount of debris were found inside the fuel control valve. From the investigations and evidences, it was concluded that the engine flame blow-out was due to blockage of fuel flow when the air flow was almost steady. Assessment and control of debris in fuel accessories, the periodicity of inspection, and cleaning are very important for maintaining a stable flame throughout the mission. Also understanding the blow-out mechanism in an aero gas turbine engine during maneuvers is necessary to address blow-out issues.