Blade Tip Gas Impingement Cooling for Grain Growth Control
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Solution Overview
Problem
Conventional cooling methods for rotor blade tips during laser cladding and repair processes fail to achieve desired cooling rates, leading to grain growth and durability issues with weld fillers, resulting in early engine removals.
Innovation Solution
A gas impingement in-process cooling system is implemented, where perforated tubular diffusers are positioned on both sides of the rotor blade tip to direct high-pressure gas impingement cooling during the deposition of materials, using a controller to synchronize the cooling with the deposition head's movements and operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling methods are used to cool base materials during laser cladding, then some cooling effect is achieved, but desired cooling rates are not reached leading to grain growth in refined microstructures
Solution Approach 1:
The patent employs gas impingement cooling where high-pressure gas flows are directed through perforated tubular bodies positioned close to the deposition zone. This pneumatic approach achieves substantially higher cooling rates compared to conventional conduction-based cooling methods, effectively controlling grain growth in the refined microstructures while cooling the base materials.
Solution Approach 2:
The cooling system applies different cooling intensities to different regions: high cooling rates are applied locally to the refined microstructures through the perforated tubular bodies positioned near the deposition head, while moderate cooling is applied to the base materials. This localized differentiation achieves the desired microstructure refinement without excessive thermal stress in the base material.
2Reliability
If weld fillers are used for rotor blade tip repairs, then repair is achieved, but weld durability is insufficient leading to early engine removal
Solution Approach 1:
The patent controls thermal parameters during the laser cladding process, including cooling rates and temperature gradients, to produce welds with refined microstructures and superior mechanical properties. By optimizing these thermal parameters, the resulting welds exhibit enhanced durability and reliability, eliminating the premature failure issues associated with conventional weld fillers.
Solution Approach 2:
The process creates composite microstructures within the weld zone by controlling the solidification process under high cooling rates. The refined microstructures formed during laser cladding produce a composite-like material structure with improved strength and durability characteristics, resulting in welds that significantly extend engine service life.
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 provides high cooling rates, minimizing grain growth and achieving strong, durable welds that extend engine life and reduce maintenance needs.
Implementation Method 1
The gas impingement assembly may include first impingement diffusers and second impingement diffusers. The support structure may support the first and second impingement diffusers at opposite sides of the base materials in first and second trailing positions relative to the deposition head, respectively, and the supply system may supply the first and second impingement diffusers with the impingement gas.
Implementation Method 2
a gas impingement in-process cooling system... where perforated tubular diffusers are positioned on both sides of the rotor blade tip to direct high-pressure gas impingement cooling
Data Source
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AI summary
A blade repair apparatus (401) is provided and includes a deposition head (420; 720; 110) which is movable relative to base materials (411; 711; 1112) and configured to execute a repair operation that includes a deposition of additional materials (421; 721; 1121) onto the base materials (411; 711; 1112) during deposition head (420; 720; 110) movements, a temperature control system (430) including a temperature regulating assembly (431) coupled with the deposition head (420; 720; 110) in a trailing position and a controller (440). The controller (440) is operably coupled to the deposition head (420; 720; 110) and the temperature control system (430). The controller (440) is configured to control the deposition head (420; 720; 110) movements and depositional operations of the deposition head (420; 720; 110). The controller (440) is configured to control the temperature control system (430) such that the temperature regulating assembly (431) controls temperatures of at least the base materials (411; 711; 1112) and the additional materials (421; 721; 1121) during at least the deposition head (420; 720; 110) movements and the depositional operations.