Gas Turbine Blade Particle Deflector for Cooling Passage Blockage
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Solution Overview
Problem
In gas turbine turbine aerofoil components, complex cooling passage geometries lead to particle buildup in regions susceptible to blockage, particularly at the blade tip, where particles are centrifuged into the radially outer tip sections and adhere to hot internal walls, restricting cooling air passage and potentially causing overheating and component failure.
Innovation Solution
A particle deflector means is integrated within the cooling fluid passage to deflect denser particles away from regions prone to buildup, directing them towards a downstream dust hole, using an arcuate deflector wall or segmented structure that extends between the leading and trailing edges, with optional angled internal surfaces to further redirect particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If complex cooling passage geometry is used in the blade tip, then cooling efficiency is improved, but particle buildup in the radially outer tip sections increases
Solution Approach 1:
The cooling passage is divided into multiple sections with different geometries. The passage includes a radially inward section, a circumferential section, and a radially outward section, allowing particles to be directed toward the dust hole while maintaining cooling effectiveness in each zone.
Solution Approach 2:
A dust hole is introduced as an intermediary feature that captures particles before they can accumulate in the cooling passages. The dust hole acts as a trap that removes particles from the cooling air flow, preventing them from reaching and blocking the cooling holes.
2Reliability
If dust holes are positioned downstream of the second labyrinth fin seal, then hot mainstream gas flow into the blade is prevented, but the leading edge passage tip region and shroud cooling scheme become susceptible to particle buildup
Solution Approach 1:
The dust hole is positioned upstream of the second labyrinth fin seal to intercept particles before they can travel along the cooling passages to the shroud and leading edge regions. This preliminary particle removal prevents accumulation in vulnerable areas while maintaining the pressure barrier against hot gas intrusion.
Solution Approach 2:
The cooling passage geometry is modified locally in the tip region to create a particle collection zone that directs particles toward the dust hole. The passage cross-sectional area and orientation are adjusted in specific zones to enhance particle separation without compromising overall cooling performance.
3Object-generated harmful factors
If particles are allowed to centrifuge into the radially outer tip sections, then particle removal from the main cooling flow is achieved, but particles adhere to hot internal end-walls and build up layer upon layer
Solution Approach 1:
The dust hole is designed to capture the centrifuged particles that would otherwise adhere to the cooling passage walls. By providing a dedicated particle collection point, the harmful centrifugal particle migration is converted into a beneficial particle removal mechanism, extending component life.
Solution Approach 2:
Particles are extracted from the cooling air flow at a specific location within the passage. The dust hole serves as an extraction point where particles are removed from the flow and deposited in a collection zone, preventing their subsequent adhesion to the cooling passage walls and cooling holes.
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 solution effectively prevents particle accumulation in critical areas, extending the component's lifespan by ensuring cooling air passages remain unobstructed and reducing the risk of overheating and failure.
Implementation Method 1
as more complex cooling passage geometry is used in the blade tip, especially where a blade shroud is present, the particles block can still block the cooling air passages. In prior art designs these foreign particles are centrifuged into the radially outer tip sections of the passages.
Data Source
AI summary
An aerofoil for a gas turbine engine, the aerofoil comprises a leading edge and a trailing edge, pressure and suction surfaces and defines therebetween an internal passage for the flow of cooling fluid therethrough. A particle deflector means is disposed within the passage to deflect particles within a cooling fluid flow away from a region of the aerofoil susceptible to particle buildup and subsequent blockage, such as a cooling passage for a shroud of a blade.