Method for producing a near-surface cooling passage in a thermally highly stressed component, and component having such a passage
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Solution Overview
Problem
Current methods for producing near-surface cooling passages in thermally highly stressed components, such as those in gas turbines, are costly and result in high scrap rates due to complexity, making them inefficient and difficult to retrofit or rework existing components.
Innovation Solution
A method involving the creation of channels in the component surface for embedding cooling tubes, filled with high-temperature solder and covered with an oxidation-resistant layer, using EDM for hollowing and LMF for coating, allowing for efficient near-surface cooling with reduced material waste and increased service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional casting methods with hollow core technique are used to produce near-surface cooling passages, then cooling efficiency is improved, but production cost increases and scrap rate becomes high
Solution Approach 1:
The cooling passage production is segmented into two independent stages: first creating the channel structure through material removal, then embedding the cooling tube as a separate component. This segmentation allows each stage to be optimized independently, reducing overall complexity and scrap rate while maintaining cooling efficiency.
Solution Approach 2:
The channel is hollowed out in advance through EDM before the cooling tube is inserted. This preliminary action prepares the receiving structure, allowing the cooling tube to be precisely positioned and embedded with filling material, thereby reducing production complexity and improving manufacturability.
2Use of energy by moving object
If complex cooling devices and configurations are implemented to achieve higher combustion temperatures, then thermal efficiency is improved, but device complexity increases and production problems arise
Solution Approach 1:
The cooling tube is extracted as a separate, embeddable component rather than being integrated into the component body through complex casting processes. This extraction simplifies the overall device complexity while maintaining the near-surface cooling configuration needed for high thermal efficiency.
3Temperature
If near-surface cooling passages are produced using traditional methods, then cooling performance is improved, but the ability to retrofit or rework existing components is lost
Solution Approach 1:
By separating the cooling passage into an embeddable tube component and the channel structure, the system becomes modular. This allows existing components to be retrofitted by simply inserting the cooling tube into pre-prepared channels, restoring cooling performance without requiring complete component replacement.
4Temperature
If cooling passages are integrated directly into component walls during casting, then cooling effectiveness is improved, but production precision and crack risk increase
Solution Approach 1:
The cooling system is segmented into the channel structure and the separate cooling tube. The channel is precisely formed by EDM, and the cooling tube is embedded with filling material that ensures precise positioning and secure attachment, thereby achieving high manufacturing precision while reducing crack risks associated with integrated casting.
Solution Approach 2:
Temperature-resistant filling material acts as an intermediary between the cooling tube and the channel walls. This filling material ensures precise positioning of the cooling tube, provides thermal contact, and reduces stress concentrations that could lead to cracking, thereby improving manufacturing precision and reliability.
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 method enables cost-effective and efficient near-surface cooling with reduced scrap rates, allowing for improved cooling performance and extended service life, including the ability to retrofit existing components, while minimizing the risk of crack development and optimizing heat transfer.
Implementation Method 1
In this case, the channel in the component is hollowed out by means of a material-removing process, in particular by spark erosion by means of an EDM electrode
Implementation Method 2
inserting a cooling tube into the channel; filling the channel, with the cooling tube inserted, with a temperature-resistant filling material in such a way that the inserted cooling tube is embedded into the filling material
Implementation Method 3
covering the channel, with the cooling tube embedded, with an anti-oxidation, temperature-stable cover layer
Data Source
Figure 1~4
Figure 5~6
Figure 7a~7d
AI summary
The invention refers to a method for producing a near-surface cooling passage (17) in a thermally highly stressed component (14), which comprises the following steps: a) providing a component (14) which has a surface (18) on a hot side in a region which is to be cooled; b) letting a channel (19) into the surface (18); c) inserting a cooling tube (20) into the channel (19); d) filling the channel (19), with the cooling tube (20) inserted, with a temperature-resistant filling material (21) in such a way that the inserted cooling tube (20) is embedded into the filling material (21), leaving free an inlet (17i) and an outlet (17o); and e) covering the channel (19), with the cooling tube (20) embedded, with an anti-oxidation, temperature-stable cover layer (22). The method is inexpensive and can be used in a flexible manner in the most diverse situations in order to save cooling medium or to reduce the thermal load.