Gas Turbine Blade Film Cooling Protrusion Design
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Solution Overview
Problem
Gas turbine blades face instability and uneven cooling due to the separation phenomenon in film cooling holes, leading to inconsistent heat transfer and potential surface deformation or cracking under high temperatures.
Innovation Solution
The design includes film cooling holes with protrusions on the inside surfaces of the outlets, specifically configured in certain sections of the blade's outer surface to guide cooling air effectively and enhance heat transfer, minimizing temperature rise and maintaining stable cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the diffusion angle of the film cooling hole is increased to enhance cooling air delivery, then the cooling effect is improved, but flow separation occurs inside the expansion portion causing inconsistent cooling air flow
Solution Approach 1:
The film cooling hole is divided into multiple sections: a straight section, an expansion section with controlled diffusion angle, and a curved section. This segmentation allows each section to perform its specific function - the straight section provides stable flow, the expansion section gradually increases diameter for controlled diffusion, and the curved section directs flow onto the blade surface, thereby resolving the contradiction between cooling effectiveness and flow consistency
Solution Approach 2:
The film cooling hole employs a curved section that dynamically adapts the flow direction to match the blade surface geometry. The curved section's angle is specifically designed to align with the blade's suction or pressure surface, allowing the cooling air to follow the surface contour and maintain consistent attachment, thus improving both cooling effect and flow stability
2Temperature
If film cooling holes are used to cool turbine blade surfaces, then blade temperature is reduced, but localized heat stress causes surface deformation or cracking in middle areas
Solution Approach 1:
The invention applies different geometric configurations to different sections of the film cooling hole based on local requirements. The expansion section uses a controlled diffusion angle suitable for the middle areas where cooling is most needed, while the curved section is specifically angled to match the local blade surface geometry. This local optimization ensures uniform cooling distribution and prevents localized heat stress that could lead to deformation or cracking
Solution Approach 2:
The film cooling holes are pre-configured with specific geometric features (straight section, expansion section, curved section) before installation on the turbine blade. These pre-designed features ensure that cooling air is delivered with the correct flow characteristics and direction to achieve uniform cooling distribution across the blade surface, preventing localized overheating and thermal stress before they can cause damage
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 configuration stabilizes the cooling air flow, enhances heat transfer performance, and maintains consistent cooling efficiency across the turbine blade's surface, reducing the risk of thermal stress and deformation.
Implementation Method 1
In film cooling, relatively cool air obtained from the compressor is ducted to internal chambers of the turbine blades and discharged through small holes provided in the blade walls. This air provides a thin, cool, insulating blanket along the external surfaces of the turbine blade.
Implementation Method 2
a protrusion formed on an inside surface of an outlet of at least one film cooling hole disposed in exactly one surface section of the outer surface... stabilizes the cooling air flow, enhances heat transfer performance, and maintains consistent cooling efficiency
Implementation Method 3
The film cooling hole includes an inlet having a circular cross-section through which flows the cooling air supplied to the interior of the turbine blade... enhances heat transfer performance
Data Source
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AI summary
A gas turbine blade includes a turbine blade having an outer surface divided according to surface sections arranged from a leading edge to a trailing edge; a plurality of film cooling holes formed in the outer surface, each film cooling hole including a cooling channel and an outlet communicating with the cooling channel to discharge cooling air to the outer surface; and a protrusion formed on an inside surface of the outlet of at least one film cooling hole disposed in exactly one surface section of the outer surface. The blade's outer surface is divided into three surface sections respectively corresponding to thirds of a length of the outer surface, from the leading edge to the trailing edge, and including first and third surface sections adjacent to the leading and trailing edges, respectively, and a second surface section in which the protrusion occurs between the first and third surface sections.