A Novel Approach to Dirt Mitigation for Combustor Walls

Abstract Ingestion of particulate within combustor wall regions, which commonly employ double wall cooling schemes with impingement and effusion cooling, lead to undesirable consequences that impact cooling performance. Numerous studies on double wall liners have demonstrated these negative impacts dirt deposition has on cooling performance; however, to this point, little has been reported to have found an effective means to mitigate dirt deposition. In the current study, a novel design was investigated that added an upstream impingement plate to the common double wall design, resulting in a triple wall liner. The purpose of the additional impingement plate is that it allows for a sacrificial middle impingement plate to capture the dirt prior to the flow impacting the effusion plate where heat transfer is most critical. Several parameters such as impingement hole diameter, dirt injection mass, and plate-to-plate spacing were evaluated for different configurations. Using the triple wall design, the data indicates that dirt deposition on the effusion plate is reduced by as much as 87% compared to the effusion plate of a double wall design while also reducing cooling hole blockage. Additionally, cooling features were integrated on the middle impingement plate surface, which further reduced deposition on the effusion plate by 25% compared to a triple wall without features. Overall, the results in this study show that a triple wall design significantly reduces dirt deposition on the effusion plate leading to less flow blockage as compared to a double wall, making them desirable for improved liner durability.