Turbine Fan Blade Root Stress Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fan blade designs for turbomachines face challenges in managing shear forces and stress distribution, leading to increased mass and potential premature wear due to oversized spoilers and uneven stress distribution between blades and wedges.
Innovation Solution
The design incorporates upstream and downstream excrescences on the blade roots to increase the axial span length, distributing stress flow over a greater area and reducing local stresses through a parallel arrangement, with concave and convex shapes to facilitate stress diffusion and improve stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spoiler of the shim is oversized in the axial direction to resist shear forces, then the shear force resistance is improved, but the mass of the fan rotor increases significantly
Solution Approach 1:
The invention divides the stress flow path into two parallel paths: one through the blade root and another through the shim spoiler. This segmentation allows the spoiler to be smaller since it only needs to carry a portion of the shear forces, reducing the mass increase while maintaining overall strength
Solution Approach 2:
The invention changes the axial dimension parameter of the spoiler by trimming the upstream end of the blade root, which allows the spoiler to be smaller than in conventional designs while still providing adequate shear force resistance through the parallel stress distribution
2Weight of moving object
If the upstream end of the blade root is trimmed to compensate for spoiler oversizing, then the mass is reduced, but the blade root exerts significant contact forces on the groove side walls leading to premature wear
Solution Approach 1:
The invention optimizes the axial dimension parameter of the blade root to match the groove length, ensuring full utilization of the groove bearing surface while distributing contact forces evenly, thereby preventing premature wear
3Device complexity
If the stress flow passes through the blade and then through the shim in a series assembly, then the structural simplicity is maintained, but the stresses in the blade remain high and are not reduced
Solution Approach 1:
The invention segments the stress flow path into parallel pathways through the blade root and the shim spoiler, transforming the series assembly into a parallel assembly. This reduces the stress concentration in the blade while maintaining structural integrity
Solution Approach 2:
The shim acts as an intermediary element that provides an additional stress flow path parallel to the blade root, thereby reducing the load on the blade while maintaining the overall structural simplicity of the assembly
Data Source
Figure 1
Figure 2~6
Figure 4~5
AI summary
The invention relates to a vane for a turbine engine. The vane (12') has a blade (13') and a root (18') to be inserted into an axial groove of a turbine engine disc. The upstream end (450') of the root is connected to a radially inner end (430') of the leading edge (431') of the blade by the upstream end of a linking area having an recess in the downstream direction, such that said radially inner end of the leading edge of the blade is located further downstream than the upstream end of the root.