Experimental study on failure of the scratched engine intake pipe under high temperature air burning

Air intake pipe is located in high temperature region of aeroengine, the leak caused by high temperature gas burning is a possible failure mode. In this paper, the tolerances of working pressures and high-temperature air burning of the intake pipe were experimental investigated. A pipe flame burning test bench with double zone heating and air pressurization was designed, which simulated the working temperature (382°C), air pressure (static and transient) and high temperature burning (500°C, 800°C and 1000°C for 3 minutes respectively) simultaneously. In these circumstances, the tolerance performances of the pipe with or without scratches was compared. There were bulge and multiple microcracks at the burning failure of all pipes. The results showed that the burning failure temperature and time of the scratched pipe were less than those of the intact pipe. The burning failure temperature of the scratched pipe was lower than 1000°C (about 940 ∼ 980°C), and corresponding failure time is less than 3 minutes. The failure mechanism under burning was obtained by the micro morphology of fracture. It provides a reference for fault evaluation and reliability analysis of engine intake pipeline.