Composite Foam Cooling Passages for Turbomachine Airfoils

The patent employs foam structures with controlled porosity to create cooling passages. The foam material provides a three-dimensional network of interconnected pores that enable efficient coolant flow and heat transfer throughout the component volume, achieving superior cooling efficiency compared to traditional hollow passages while maintaining manufacturability through foam infiltration or expansion processes

The patent utilizes composite foam structures combining different materials (e.g., metal foams, ceramic foams, or polymer-fiber composites) to achieve optimal thermal and mechanical properties. These composite foam materials provide enhanced heat transfer characteristics and structural integrity simultaneously, resolving the contradiction between manufacturing ease and cooling efficiency

The foam structure's cellular architecture provides both cooling passages and structural support. The three-dimensional pore network distributes thermal loads and mechanical stresses throughout the material, maintaining structural integrity while enabling efficient cooling. The cell walls and struts of the foam act as load-bearing elements that prevent catastrophic failure

The patent implements variable density foam structures where the pore size, cell structure, and material composition are locally optimized to match thermal and mechanical requirements at different locations. High-density regions provide structural support in high-stress areas, while low-density regions enhance cooling efficiency in high-heat-flux zones, achieving both goals simultaneously

The patent achieves controlled density variations by modifying foam formation parameters such as expansion ratio, cross-linking density, or material composition during the foaming process. These parameter changes create gradient structures or zoned density distributions that optimize heat transfer pathways without requiring complex post-processing or assembly operations, maintaining manufacturing simplicity

The desired density distribution and pore structure are built into the foam material during the initial foaming or infiltration process rather than requiring subsequent machining or assembly. The foam is formed in-situ or pre-formed with the exact density gradient needed, eliminating the need for complex manufacturing steps to create the thermal management structure