Turbine Wheel Blade Platform Cooling via Segmented Damping Sheets
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Solution Overview
Problem
Existing turbine wheel designs for turbine engines face challenges in effectively cooling blade platforms, which are prone to high temperatures, leading to temperature gradients and potential cracking, while previous solutions like cooling air circuits are complex, costly, and weight-increasing.
Innovation Solution
The design incorporates air-passing holes in damping sheets with radial projections on the platforms, creating airflow spaces for improved cooling, enhancing heat exchange and maintaining ventilation air flow efficiency by minimizing circumferential clearance between sheets and tangs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air circuits are provided in sealing members made of thick material blocks, then blade platforms can be cooled effectively, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The sealing member is segmented into multiple thin sheets instead of using a single thick block, with air-passing holes distributed throughout the sheets to provide cooling pathways without requiring complex internal circuits
Solution Approach 2:
The sealing member is designed as a porous structure with multiple air-passing holes in the sheets, allowing cooling air to flow through easily without requiring thick material blocks or complex internal channels
2Temperature
If cooling air circuits are provided in sealing members, then blade platforms can be cooled, but the weight of the sealing members increases
Solution Approach 1:
The sealing member is divided into multiple thin sheets rather than using a single thick block, reducing overall material usage and weight while maintaining cooling functionality through distributed air-passing holes
Solution Approach 2:
The use of porous sheets with air-passing holes reduces material density and weight compared to solid thick blocks, while still providing effective cooling air flow paths to the blade platforms
3Manufacturing precision
If radial clearance is increased between sheets and platform faces, then assembly tolerance is improved, but ventilation air flow efficiency decreases
Solution Approach 1:
The radial clearance parameter is optimized to a specific small value that balances assembly tolerance requirements with ventilation air flow efficiency, ensuring sufficient air flow without excessive clearance
Solution Approach 2:
The sheets are designed to bear radially against the platform faces with minimal contact (partial action), providing just enough support and sealing while maintaining optimal air flow clearance without excessive constraint
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 reduces temperature gradients on blade platforms, improves cooling efficiency, and maintains maximum ventilation air flow, thereby extending platform lifespan and reducing manufacturing costs.
Implementation Method 1
A portion of the air flow passing over the teeth of the disk in operation passes via the holes in the sheets, impacts against the internal faces of the platforms, and then flows between the sheets and the platforms so as to cool the platforms and reduce their temperature gradients
Implementation Method 2
The projections formed on the radially internal faces of the platforms bear against the sheets and hold them spaced apart from the internal faces of the platforms so as to create one or more air flow spaces
Implementation Method 3
damping members are mounted for the purpose of dissipating the energy of the vibration to which the blades are subjected in operation, dissipation being by rubbing against the platforms
Data Source
AI summary
A turbine wheel for a turbine engine, comprising a disk carrying blades, each having a platform carrying an airfoil and connected by a tang to a root, and sealing and damping sheets housed in the inter-tang spaces, the platforms including projections on their radially internal faces against which the sheets bear radially in operation, in order to define radial clearance and create at least one space between the sheets and the platforms, and the sheets including holes for feeding air to the or each space.