Gas Turbine Airfoil Tangential Stacking Optimization
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to flow discontinuities and turbulence caused by high-speed air interacting with fan airfoils, leading to irreversible propulsive losses, which are complex to address through existing design modifications.
Innovation Solution
The airfoil design for gas turbine engines is optimized by controlling the tangential leading edge, tangential stacking offset, and tangential trailing edge positions relative to the span position, with specific non-dimensional ratios (Y_LE - Y_d) / (Y_d - Y_TE) at various span positions, to minimize losses and enhance aerodynamic functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan rotates at high speed to increase productivity, then the propulsive efficiency deteriorates due to flow discontinuities and shocks
Solution Approach 1:
The patent applies local quality by optimizing specific geometric parameters of the airfoil at different span positions. The non-dimensional ratios (Y_LE - Y_d) / (Y_d - Y_TE) are controlled to have specific values (about 1.1 at 100% span, about 1.3 at 90% span, about 1.8 at 60% span, about 0.75 at 50% span) to create locally optimized flow characteristics that reduce shocks and turbulence at high rotation speeds
Solution Approach 2:
The patent employs parameter changes by modifying the tangential projection parameters of the airfoil geometry. By controlling the leading edge position Y_LE, stacking offset Y_d, and trailing edge position Y_TE to achieve specific non-dimensional ratios across the span, the design changes the flow field characteristics to minimize propulsive losses while maintaining high fan rotation speeds
2Device complexity
If conventional airfoil designs are used to maintain device complexity at acceptable levels, then propulsive efficiency deteriorates due to irreversible losses and turbulence
Solution Approach 1:
The patent achieves reduced propulsive losses through precise parameter control of existing airfoil geometry rather than fundamental design changes. By specifying target values for the non-dimensional ratios (Y_LE - Y_d) / (Y_d - Y_TE) at different span positions, the invention optimizes conventional airfoil designs to minimize turbulence and irreversible losses while maintaining manufacturing feasibility
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
In one exemplary embodiment, an airfoil for a turbine engine includes pressure and suction sides extending 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 geometry corresponds to tangential leading and trailing edge curves and a tangential stacking offset curve. The airfoil extends from a root. A zero tangential reference point corresponds to tangential center of the root. YLE corresponds to a tangential distance from a leading edge to the reference point at a given span position. YTE corresponds to a tangential distance from a trailing edge to the reference point at a given span position. Yd corresponds to a tangential stacking offset at a given span position. (YLE-Yd)/(Yd-YTE) at 40% span position is about 1.5 and (YLE-Yd)/(Yd-YTE) at 20% span position is about 2.