Gas Turbine Airfoil Tangential Stacking Offset Optimization
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to flow discontinuities and turbulence caused by fan blades, leading to irreversible propulsive losses, which are complex to address in existing engine designs.
Innovation Solution
The design of fan blades with specific tangential stacking offset curves, featuring critical points at defined span positions and R d /Y d ratios, ensures optimal aerodynamic functionality and thermal efficiency by minimizing tangential stacking offset variations along the span.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fan blades operate at high rotational speeds to increase power output, then power increases, but flow discontinuities and shocks occur causing propulsive losses
Solution Approach 1:
The patent applies local quality by varying the tangential stacking offset at different span positions along the fan blade. Specifically, the offset is optimized in different regions (root, mid-span, tip) to control flow characteristics locally, reducing shocks and flow discontinuities while maintaining high rotational speeds for power output
Solution Approach 2:
The patent implements dynamics by using a non-uniform tangential stacking offset distribution that creates dynamic flow control along the blade span. The offset curve with critical points at specific span positions (e.g., 20-30% and 70-80% span) enables the blade to adapt flow characteristics dynamically across different radial positions, reducing turbulence and energy losses during high-speed operation
2Adaptability or versatility
If tangential stacking offset varies significantly along the span, then design flexibility increases, but turbulence and flow discontinuities increase
Solution Approach 1:
The patent applies parameter changes by optimizing the tangential stacking offset values at specific span positions rather than using a uniform offset. The offset is varied within controlled ranges (e.g., 0.02-0.04 at root, 0.04-0.06 at mid-span, 0.06-0.08 at tip) to maintain design flexibility while minimizing turbulence and flow discontinuities
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
An airfoil of a turbine engine includes pressure and suction sides that extend in a radial direction from a 0% span position at an inner flow path location to a 100% span position at an airfoil tip. The airfoil has a relationship between a tangential stacking offset and a span position that is at least a third order polynomial curve that includes at least one positive and negative slope. The positive slope leans toward the suction side and the negative slope leans toward the pressure side. An initial slope starting at the 0% span position is either zero or positive. The first critical point is in the range of 5-15% span.