Non-axisymmetric Turbine Blade Platform Reducing Vortex Losses
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Solution Overview
Problem
Turbine engine blades experience significant energy dissipation due to parasitic vortices at the inter-profile surface, which reduces the efficiency of turbomachines, particularly in high-speed aeronautical applications, and existing designs have not effectively mitigated these losses.
Innovation Solution
The blade design features a platform surface with an axially located hollow intrados part in the downstream half and a raised extrados part in the upstream half, reducing parasitic vortex flows by stabilizing the flow and minimizing pressure gradients across the inter-profile surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional axisymmetric platform surface is used, then the manufacturing is simple and the structure is regular, but parasitic vortex flows occur at the inter-profile surface causing significant energy dissipation
Solution Approach 1:
The patent applies asymmetry by introducing a non-axisymmetric platform surface with specific geometric features (hollows and bumps) that break the rotational symmetry of conventional designs. This asymmetric geometry is strategically designed to control the pressure distribution and eliminate parasitic vortex flows at the inter-profile surface, directly addressing the energy dissipation problem while accepting increased geometric complexity.
Solution Approach 2:
The patent implements local quality by creating localized geometric features (hollows and bumps) at specific locations on the platform surface rather than uniform modifications. These localized features are positioned to specifically address flow separation zones and pressure gradient issues at the inter-profile regions, allowing targeted control of parasitic vortices without complicating the entire platform structure.
2Loss of energy
If the platform surface geometry is modified to reduce parasitic vortices, then energy dissipation decreases, but the manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying specific geometric parameters of the platform surface (curvature radii, depths and positions of hollows and bumps) to optimize flow control. These parameter adjustments are designed to achieve the desired flow stabilization and vortex reduction while maintaining manufacturability through controlled variations in surface geometry that can be produced using conventional or near-net-shape manufacturing processes.
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 design significantly reduces parasitic vortex flows and enhances the efficiency of the blade by stabilizing the flow, leading to lower energy dissipation and maintaining a moderate cost of production.
Implementation Method 1
minimizing pressure gradients across the inter-profile surface
Implementation Method 2
reduces parasitic vortex flows by stabilizing the flow
Data Source
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AI summary
Blade (10) for the bladed disc of a turbomachine comprising an aerofoil, and at least one platform at one end of the aerofoil, the blade (10) being able to be positioned, together with a plurality of substantially identical blades, in such a way as to form a ring, the platform surface exhibiting an extrados profile (80) and an intrados profile (85) along the extrados and the intrados respectively. In the blade, the intrados profile (85) has a recessed intrados part (I) situated axially in the downstream half of the aerofoil. This configuration improves the efficiency of the blade.