Turbomachine Stator Vane Curved Stacking Line
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Solution Overview
Problem
The increase in bypass ratio in turbojet engines, aimed at improving propulsive efficiency, leads to increased diameter of turbomachines, which is constrained by minimum ground clearance, resulting in higher drag and noise due to acoustic interactions between fan blades and stator vanes, particularly at the tip end of the blades.
Innovation Solution
A turbomachine stator blade design with a curvature in the stacking line between the root and tip ends, reducing the length of the nacelle and maintaining a minimum axial distance, thereby reducing drag and noise, by smoothing the transition between leading and trailing edges and minimizing vortex formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bypass ratio is increased to improve propulsive efficiency, then the turbomachine diameter increases, but the ground clearance constraint is violated and drag increases
Solution Approach 1:
The stacking line of the stator blade is designed with a curvature oriented from downstream to upstream in a plane passing through the longitudinal axis. This curvature modifies the blade geometry to reduce the axial length required, thereby allowing a shorter nacelle while maintaining aerodynamic performance and ground clearance constraints.
Solution Approach 2:
The invention changes the geometric parameters of the stator blade by introducing a curved stacking line with specific orientation and location (in the vicinity of the tip end). This parameter modification enables reduction of the nacelle length and drag while preserving the bypass ratio benefits.
2Length of stationary object
If the axial distance between fan blades and stator vanes is reduced to shorten the nacelle, then the nacelle length decreases, but acoustic interactions and noise increase
Solution Approach 1:
The curved stacking line oriented from downstream to upstream modifies the flow path and reduces abrupt changes in flow direction. This curvature smoothing effect minimizes vortex formation and acoustic interactions between fan blades and stator vanes, allowing shorter axial distance without excessive noise increase.
Solution Approach 2:
The curvature is specifically located in the vicinity of the tip end of the stacking line, applying the geometric modification where it is most effective for reducing noise while maintaining overall blade functionality and flow straightening capability.
3Ease of manufacture
If stator blades have abrupt sweep angle changes to simplify manufacturing, then manufacturing is easier, but vortex phenomena and noise increase
Solution Approach 1:
Instead of abrupt sweep angle changes, the invention employs a continuous curvature in the stacking line. This curved geometry smoothly transitions the blade sections from root to tip, eliminating abrupt directional changes that generate vortices, while remaining manufacturable through standard aerodynamic shaping processes.
Data Source
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AI summary
The invention relates to a flow-straightener vane (1) of a bypass turbomachine (100) of longitudinal axis (X), the vane (1) comprising a plurality of vane sections (2) stacked radially with respect to the axis (X) along a stacking line (L) between a root end (3) and a tip end (4), each vane section (2) comprising a pressure-face surface (7) and a suction-face surface (8) extending axially between an upstream leading edge (5) and a downstream trailing edge (6) and being tangentially opposed. According to the invention, between the leading (5) and trailing (6) edges of each vane section (2) there is formed a profile chord (CA) the length of which is substantially constant between the tip end (4) and the root end (3), and the stacking line (L) exhibits a curvature in a plane passing more or less through the axis (X) and through the stacking line (L), situated in the vicinity of the tip end (4) and oriented from downstream towards upstream.