Variable Porosity Combustor Liner Cooling

The combustor liner employs variable porosity design where different regions have different cooling hole densities and sizes. High porosity regions are positioned in areas requiring enhanced cooling such as near the fuel injector and in the combustion chamber, while lower porosity regions are located in areas with lower thermal loads. This local differentiation of cooling characteristics directly addresses the insufficient cooling problem in specific regions while maintaining manufacturability through integrated molding techniques.

The patent achieves variable porosity by systematically varying geometric parameters including hole diameter, hole spacing, and hole depth across different regions of the combustor liner. The cooling hole diameter ranges from 0.002 to 0.05 inches, with spacing and depth adjusted to create the desired porosity gradient. This parameter-based approach enables sophisticated cooling control while avoiding complex multi-component assemblies, thus improving cooling effectiveness without excessive structural complexity.

The combustor liner employs partial cooling action by providing enhanced cooling flow only to specific critical regions rather than uniformly across the entire liner. High porosity zones are concentrated in areas experiencing maximum thermal exposure such as near the fuel injector and in the combustion chamber, while adjacent regions receive proportionally less cooling. This targeted approach reduces liner temperature in critical areas without excessively increasing overall cooling air consumption, thereby protecting engine efficiency.