Impact of Manufacturing Variability on Combustor Liner Durability

This paper presents a probabilistic model that quantifies the impact of manufacturing variability on combustor liner temperature and low cycle fatigue life. This model is applied to a gas turbine engine combustor for a commercial aircraft and assessed using combustor liner wall temperature and outlet gas temperature measurements. A probabilistic analysis shows that the model estimates cup-to-cup outlet temperature variations and liner wall temperature variations consistent with these measurements. Furthermore, this analysis shows that the typical liner life is 25 percent less than the life estimated using deterministic methods. In addition, approximately 99 percent of the combustors designed using deterministic methods will fail earlier than predicted. A sensitivity analysis shows that the variability in combustor unmixedness is the key driver of liner life.