Variable Stator Blade Tilt for Turbofan Noise and Friction
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Solution Overview
Problem
Existing compressor stages with fixed stator blade inclinations face efficiency losses due to increased surface area and friction, while attempts to reduce noise through tilting stator blades result in undesirable pressure gradients and reduced efficiency.
Innovation Solution
The compressor stage features stator blades with a variable angle of inclination along their height, allowing for greater inclinations in radially outer areas for noise reduction and minimal or no inclination near the stator hub to reduce friction losses, enabling adaptive design for efficiency and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If stator blades are tilted to reduce noise, then noise is reduced, but efficiency decreases due to increased surface area and friction losses
Solution Approach 1:
The stator blade is designed with different inclination angles at different radial positions. The radially outer section has a greater inclination angle for noise reduction, while the radially inner section has a smaller inclination angle to minimize friction losses. This local differentiation allows each section to optimize for its specific function.
Solution Approach 2:
The stator blade is divided into at least two distinct sections along its height: a radially outer blade section and a radially inner blade section. Each section can have different geometric properties, particularly different inclination angles, allowing independent optimization of noise reduction and efficiency characteristics.
2Object-affected harmful factors
If stator blades are tilted to reduce noise, then noise is reduced, but pressure gradients increase causing efficiency loss
Solution Approach 1:
Different sections of the stator blade have different inclination angles tailored to their local flow conditions. The radially inner section with smaller inclination angle maintains favorable pressure gradients, while the radially outer section with greater inclination angle addresses noise generation in that region.
Solution Approach 2:
By segmenting the stator blade into multiple sections with different inclination angles, the design can independently manage pressure gradient effects in the inner region while achieving noise reduction in the outer region, avoiding the trade-off present in uniform倾斜 designs.
3Ease of manufacture
If stator blades have constant inclination angle, then manufacturing is simplified, but cannot simultaneously optimize noise reduction and efficiency
Solution Approach 1:
The stator blade is segmented into sections that can be manufactured as separate components or as distinct regions of a unified structure. This segmentation enables complex variable geometry while maintaining manufacturing feasibility through modular construction or region-specific fabrication processes.
Solution Approach 2:
The stator blade geometry transitions from static uniform inclination to dynamic variable inclination along the blade height. This allows the blade to adapt its characteristics to different flow conditions at various radial positions, optimizing both noise reduction and efficiency simultaneously.
Data Source
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AI summary
The invention relates to a compressor stage (10), in particular for a turbofan engine for aircraft, comprising: - a fan (14) rotatable about a rotational axis (X); and - a plurality of circumferentially distributed stator blades (28) arranged downstream of the fan (14), wherein the stator blades (28) each extend from a radially inner stator hub (20) to a radially outer outer casing (18), wherein an inclination angle (α) of each stator blade (28) is variable, wherein the stator blades (28) have an inclination angle (α) of less than 30° in a transition region to the outer casing (18) and a different inclination angle (α) in at least one radially further inward region.