An Experimental System for Assessing Combustor Durability

Modern gas turbine combustors are made of high temperature alloys, employ effusion cooling, and are protected by a thermal barrier coating (TBC). Gas turbine combustor failure modes, such as TBC spallation, cracking, and distortion resulting from oxidation, creep, and thermal fatigue, are driven by hot spot peak temperature and the associated thermal gradient. Standard material characterization tests, such as creep, oxidation, and low cycle fatigue are indicators of a material’s potential performance but they neither fully represent the combustor geometric/material system nor fully represent the thermal fatigue conditions a combustor is subjected to during engine operation. Combustor rig tests and/or engine cyclic endurance tests to determine the suitability of new material systems for combustors are time-consuming and costly. Therefore, a simple yet efficient test method for screening material systems under representative combustor conditions is needed. An experimental system has been developed to fill this gap. This paper discusses the configured specimen geometry, test methodology, observed test results, and a comparison with typical failure modes observed in combustors.