Turbine Rotor Blade Root Flute for Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High centrifugal forces in turbine rotor blades lead to excessive loading on the blade carrier, reducing its lifespan due to stress concentrations at the end regions, which existing designs fail to adequately address.
Innovation Solution
A flute is arranged in the concave rounded portion of the blade root, reducing the supporting area and increasing flexibility, thereby distributing mechanical loading more uniformly and reducing stress concentrations along the retention groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supporting flanks are made large to ensure positive connection and hold the blade during operation, then the reliability of blade retention is improved, but the blade carrier is subject to excessively high local loads reducing its life
Solution Approach 1:
The blade root is designed with non-uniform supporting flank distribution: the first supporting flank has a larger supporting area than the second supporting flank. This local quality variation allows the blade to maintain reliable connection while reducing stress concentrations in specific high-load regions of the blade carrier, thereby extending blade carrier life without compromising retention reliability.
2Duration of action of stationary object
If the supporting area of the supporting flank is reduced to decrease stress concentrations, then the blade carrier life is extended, but the positive connection and retention capability may be compromised
Solution Approach 1:
Instead of uniformly reducing the supporting area, the invention applies local quality by selectively reducing the supporting area of the second supporting flank while maintaining a larger supporting area on the first supporting flank. This targeted approach reduces stress concentrations in critical regions to extend blade carrier life while preserving sufficient retention capability through the first supporting flank.
Solution Approach 2:
The blade root employs asymmetric supporting flank design where the first supporting flank differs from the second supporting flank in terms of supporting area. This asymmetry allows optimized stress distribution in the blade carrier, reducing peak stresses to extend component life while maintaining adequate retention through the larger first supporting flank.
Data Source
AI summary
A turbine rotor blade for a thermal continuous flow machine, wherein a transition region and an aerodynamically shaped turbine blade connected to same, follows a blade foot for securing the turbine rotor blade to a rotor along a notional blade longitudinal axis of the turbine rotor blade from bottom to top. The blade foot has two flat end surfaces facing one another, two contoured side surfaces facing one another and joining the two end surfaces to one another, in which side surface at least one respective carrying edge is formed by creating dovetail- or fir tree-like end surface contour. The carrying edges become free edges or extend into the transition region via concave rounded portions. A channel bordering one of the two end sides is arranged in at least one concave rounded portion, the extension of which channel along the side surface is less than that of the carrying edge.