1. Field of the Invention
The invention relates to combustor baskets for gas turbine engine combustors. More particularly, the invention relates to combustor baskets of the type having nested inner and outer liners separated by a cooling air gap.
2. Description of the Prior Art
Some known types of gas turbine engines having annular combustor construction incorporate combustor baskets with nested inner and outer liners, separated by a cooling air gap. The cooling air gap is maintained at the distal downstream tip of the basket by radially outwardly directed dimples formed in the inner basket distal tip that abut against the outer liner. A standoff gap is preserved between the respective liners so long as the dimples maintain structural integrity. The inner liner is in direct communication with the combusted gas flow, experiencing higher temperature exposure than the outer liner. The combustion gas thermal and fluid contact erodes and/or distorts the inner basket during engine operation. In some operating environments dimples formed on the inner liner distal tip erode or collapse, facilitating collapsing of the cooling gap between the inner and outer liners. Diminished cooling flow hastens further thermal erosion of the combustion basket. In an effort to improve cooling airflow in the combustor basket gap between the inner and outer liners, some combustor basket designs have incorporated through holes in the inner liner circumference, especially proximal the basket distal tip portion, in order to induce radial airflow into the gap as well as axial airflow.