Microchannel Cooling for Gas Turbine Components
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Solution Overview
Problem
Conventional cooling strategies for high-temperature gas turbine components result in low heat transfer rates and non-uniform temperature profiles, leading to potential component damage and decreased turbine efficiency, with existing micro-channel cooling systems facing challenges in filler material removal and TBC system protection.
Innovation Solution
A method involving the formation of microchannels and coolant passage holes, followed by filling with a sacrificial material, applying a metallic structural coating, creating passive cooling holes or slots, and removing the filler material, with additional coating layers to enhance coolant flow and protect against TBC failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling circuits and serpentines are used, then cooling is provided to hot gas path components, but heat transfer rates are low and temperature profiles are non-uniform
Solution Approach 1:
The cooling system is segmented into multiple microchannels instead of using single large serpentine passages. This segmentation increases the total surface area for heat transfer and distributes cooling more uniformly across the component surface, resolving the contradiction between low heat transfer rates and non-uniform temperature profiles.
Solution Approach 2:
The invention transitions from two-dimensional serpentine cooling paths to a three-dimensional network of microchannels embedded within the component structure. This dimensional change allows cooling to occur throughout the component volume rather than along surface paths, significantly improving heat transfer efficiency and temperature uniformity.
2Productivity
If micro-channel cooling is implemented, then heat transfer rate and cooling efficiency are improved, but filler material removal becomes difficult and TBC system protection is compromised
Solution Approach 1:
The invention extracts the filler material removal problem by providing dedicated access holes that lead directly to the microchannels. These access holes enable complete removal of sacrificial filler material through chemical etching or other removal processes, resolving the manufacturing difficulty while preserving the microchannel cooling structure.
Solution Approach 2:
The access holes serve as intermediary pathways between the external environment and the embedded microchannels. These intermediaries facilitate the removal of filler material without requiring direct access to the microchannels themselves, thus preserving the TBC system while enabling complete filler removal.
3Reliability
If TBC system is applied for thermal insulation, then component protection from high-temperature gas flow is improved, but additional cooling air must be diverted from compressor
Solution Approach 1:
The invention merges the TBC thermal insulation function with active microchannel cooling. The TBC provides external thermal barrier protection while the microchannels provide internal active cooling, creating a hybrid system that achieves superior protection without requiring excessive cooling air diversion, thus resolving the contradiction between component protection and energy loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves cooling efficiency, reduces component temperature delta, and provides additional coolant flow routes in case of TBC failure, maintaining engine efficiency and component integrity.
Implementation Method 1
The flow of the cooling fluid may thereby cool adjacent or proximate regions of the component, through convective cooling
Implementation Method 2
the exposed outer walls of the hot gas path components may be covered with a thermal barrier coating (TBC) system, which provides thermal insulation
Data Source
AI summary
A method for providing a fluid cooling system within a high temperature component is described. At least one microchannel is formed in an external surface of the component; and one or more coolant passage holes are then formed, extending from at least one of the microchannels to an interior region of the component. A layer of a metallic structural coating is then applied over the external surface. At least one slot, or a set of relatively small passive cooling holes, are then formed through the metallic structural coating; extending into at least a portion of the microchannels. A second coating layer is then applied over the first layer. In some embodiments, a sacrificial material is deposited into the microchannels before the first coating layer is applied. Related articles are also described.