Turbine Blade Platform Cooling via Trailing Edge Depression
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Solution Overview
Problem
Turbine blades experience overheating downstream of the trailing edge, leading to reduced lifespan due to inadequate cooling, particularly when cooling air is blown out centrally.
Innovation Solution
The trailing edge opening closest to the platform is extended into the platform surface or the platform surface is locally lowered near the opening, allowing for closer blowing of cooling air, resembling film cooling, which reduces the thermodynamic load and enhances cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is blown out centrally at the trailing edge, then the trailing edge structure is thick and simple, but overheating occurs on the platform side downstream of the trailing edge
Solution Approach 1:
The patent applies local quality by creating a localized depression (cooling cavity) at the platform surface near the trailing edge opening. This depression concentrates cooling air flow precisely where needed (at the platform downstream of the trailing edge) without requiring global structural changes. The cavity depth and positioning are optimized to deliver cooling air exactly to the overheated region, resolving the temperature issue locally while maintaining overall blade simplicity.
Solution Approach 2:
The invention introduces a new spatial dimension by creating a depression or cavity in the platform surface. This vertical dimension (depth of depression) allows cooling air to be directed more effectively onto the platform surface, creating a film cooling effect. The depression depth (e.g., 0.5-2mm) provides an additional degree of freedom for optimizing cooling air distribution without affecting the overall blade thickness or trailing edge structure.
2Temperature
If the trailing edge opening is extended into the platform surface or platform is locally lowered, then cooling air blows closer to the wall improving film cooling, but the platform structure becomes more complex
Solution Approach 1:
The depression is created only in the specific region where cooling is needed (near the trailing edge opening on the platform surface), not throughout the entire platform. This localized modification minimizes structural complexity while maximizing cooling effectiveness. The depression affects only a small area (controlled by radius R1 and depth h1) rather than requiring global platform redesign.
Solution Approach 2:
The invention optimizes specific geometric parameters of the depression (depth h1, radius R1, positioning relative to trailing edge) to achieve effective film cooling. By carefully controlling these parameters, the cooling air flow is optimized to attach to and protect the platform surface without requiring complex structural modifications. The parameters are tuned to balance cooling effectiveness with manufacturing simplicity.
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 improves cooling downstream of the trailing edge, reducing thermomechanical loads and extending the turbine blade's service life by minimizing hot gas influence and potential spalling issues.
Implementation Method 1
the cooling air is blown out close to the platform in such a way that almost film cooling of the platform can be realized downstream of the trailing edge
Data Source
Figure 1~2
AI summary
The invention relates to a turbine blade (10) with an aerodynamic aerofoil (12), which extends from a bottom end (14) to a top end and comprises two aerofoil walls (16, 18) extending in between, which transversely thereto extend from a common leading edge to a common trailing edge (20), and with at least one platform (22), which extends transversely in relation to the aerofoil (12) and is arranged at one of the two ends (14) of the aerofoil (12), wherein a number of openings (28, 32) are provided in the trailing edge (20) between the bottom end and the top end. In order to reduce the thermomechanical loads in the platform (22) of the turbine blade (10), and consequently obtain a long-lasting turbine blade (10), it is provided according to the invention that either the opening (32) in the trailing edge (20) that is arranged closest to the platform surface (30) extends into the platform surface (30) or that the platform surface (30) facing the aerofoil (12) is lowered locally in the region of that opening (28) that is closest to the platform (22) concerned, and the opening (32) concerned is of such a form that it opens out into a portion (36) of the trailing edge that has become free as a result of the lowering (34).