Turbine Blade Root Protection Deflector
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Solution Overview
Problem
Gas ingestion from the hot gas flow path into the wheel spaces of low pressure turbines can cause damage to wheel rims and reduce the useful life of the turbines, especially when the engine operates at partial load or when parts are not manufactured to design specifications.
Innovation Solution
A deflector element is arranged on the shank of each blade, interposed between the blade and a spacer, to deflect any possible gas ingestion from the hot gas flow path toward the upper surface of the spacer, thereby preventing gas ingestion into the wheel spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spacers are added between wheels to physically block hot gas flow, then hot gas ingestion is reduced, but hot gas can still flow through gaps between spacer rims and wheel rims
Solution Approach 1:
The protection system is divided into multiple functional segments: the deflector element on each blade shank handles hot gas deflection at the source, while the spacer rim provides secondary blocking. This segmentation allows each component to specialize in a specific protection function, improving overall reliability compared to a single spacer approach.
Solution Approach 2:
The deflector element is positioned on the blade shank upstream of the spacer, performing preliminary deflection of hot gases before they reach the spacer. This preliminary action reduces the hot gas load on the spacer and prevents gas from entering gaps between the spacer and wheel rims.
2Productivity
If purging air flow is reduced to increase power and efficiency, then engine performance improves, but the risk of hot gas flow path ingestion into wheel spaces increases
Solution Approach 1:
The deflector element performs preliminary anti-action by deflecting hot gases away from the wheel space inlet regions before purging air would normally counteract them. This allows the system to operate with reduced purging air flow while maintaining protection, as the deflector provides the first line of defense against hot gas ingestion.
3Device complexity
If traditional spacers are used as the sole protection mechanism, then the structure is simple, but they require multi-connection systems that increase complexity and may not fully prevent gas flow through gaps
Solution Approach 1:
The invention merges two protection mechanisms into a unified system: the deflector element integrated on the blade shank combines with the spacer rim to create a layered protection system. This merging maintains relative structural simplicity while effectively preventing hot gas flow through gaps that would penetrate a single spacer approach.
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
The deflector effectively reduces the risk of gas ingestion into the wheel spaces, protecting the turbine internal parts from excessive temperature increases and extending the useful life of the wheels by preventing damage from thermal stress.
Implementation Method 1
A deflector element is arranged on the shank of each blade, interposed between the blade and a spacer, to deflect any possible gas ingestion from the hot gas flow path toward the upper surface of the spacer
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
A urbine (14), and particularly a low pressure turbine is disclosed, which comprises a plurality of rotor members (2) and spacers for arranged between rotor members, to avoid that an ingested gas flow from the hot gas flow path channel (F) reaches the wheel space (5). The rotor members each include a deflector (8). The deflector is placed in correspondence with each spacer and deflects the ingested gas flow over the upper surface of the spacer, thus preventing it to heat up the roots of the blades (4).