Turbomachine Blade Transition Area for Stability
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Solution Overview
Problem
Turbomachines, such as jet engines, face challenges in reducing the number of blades while maintaining aerodynamic and structural-mechanical stability, often resulting in complex hub constructions and potential break-away edges or steps that can lead to structural issues and reduced efficiency.
Innovation Solution
A blade design with a transition area that extends beyond one lateral edge and is severed to form an elevation offset on the other edge, allowing for wider stabilization without break-away edges, enabling larger blades with reduced numbers and improved aerodynamic performance, while maintaining a small clearance angle and facilitating manufacturing through tangential transition into the shroud.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of blades is reduced to increase aerodynamic work per blade, then blade aerodynamic performance is improved, but blade structural stability deteriorates
Solution Approach 1:
The transition area is extended in the axial direction beyond the lateral edges of the shroud, utilizing the axial dimension to provide additional stabilization without increasing the radial footprint. This allows blades to be more stable with fewer blades, resolving the contradiction between aerodynamic work and structural stability.
Solution Approach 2:
The transition area is divided into multiple sections that extend beyond the lateral edges and are severed to form elevations offset in the transverse direction. This segmentation allows the stabilization function to be distributed across multiple discrete structures rather than requiring a single massive hub construction.
2Strength
If blade stabilization is increased to prevent breaking, then blade strength is improved, but hub area construction becomes massive
Solution Approach 1:
Instead of increasing hub area construction (radial dimension), the transition area extends in the axial direction beyond the lateral edges. This dimensional shift provides blade stabilization without requiring a massive hub area, resolving the contradiction between strength and construction complexity.
Solution Approach 2:
The transition area is merged with the shroud structure, and its sections are severed to form elevations that are integral to the shroud. This merging eliminates the need for separate stabilization structures in the hub area, reducing construction complexity while maintaining blade strength.
3Productivity
If clearance angle is reduced to improve aerodynamic performance, then aerodynamic efficiency is improved, but blade stability deteriorates
Solution Approach 1:
The transition area extends in the axial direction beyond the lateral edges, providing stability in a different dimension than the clearance angle (which is a radial parameter). This allows the clearance angle to be minimized for aerodynamic efficiency while the axial extension of the transition area maintains blade stability.
4Stability of the object's composition
If transition area is extended beyond lateral edges to widen stabilization, then blade stability is improved, but break-away edges or steps may form
Solution Approach 1:
The transition area is segmented into multiple sections that are severed at specific locations to form elevations offset in the transverse direction. This segmentation allows the transition area to extend beyond lateral edges while creating discrete, controlled structures that prevent the formation of harmful break-away edges or steps, maintaining edge integrity.
Data Source
AI summary
A blade for a turbomachine, in particular a jet engine, including a shroud, having two opposite lateral edges, for delimiting a main flow channel and including a blade which extends away from the shroud, a rounded transition area being provided which encompasses the blade on its root side and is guided beyond the one lateral edge, a section of the transition area protruding beyond the one lateral edge being severed and situated in the area of the other lateral edge as an elevation offset in the transverse direction, a blade arrangement having at least two of such blades as well as a turbomachine having a plurality of such blades.