Airfoil Hump Feature Reduces Flow Separation and Heat Loads
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Solution Overview
Problem
Gas turbine engine airfoil arrays with low camber angles experience flow separation, leading to increased aerodynamic losses and convective heat loads due to fluid flow separation, which existing technologies have not adequately addressed.
Innovation Solution
Incorporating a hump feature near the leading edges of airfoils within the airfoil array, which influences fluid flow and limits separation by altering the flow passage geometry, specifically between the airfoils and endwalls, to reduce convective heat loads and enhance aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If airfoils with low camber angles are used, then aerodynamic losses are reduced, but flow separation occurs increasing convective heat loads
Solution Approach 1:
The invention applies a hump feature locally at the leading edge of airfoils where flow separation occurs. This localized geometric modification alters the flow characteristics specifically at the critical region without changing the overall airfoil camber angle, thereby maintaining low aerodynamic losses while reducing flow separation and associated convective heat loads.
Solution Approach 2:
The hump feature is positioned upstream of the airfoil leading edge to preemptively influence the flow before it enters the airfoil. This preliminary geometric modification modifies the flow attachment and reduces separation tendencies before they can develop into harmful vortices that would increase convective heat loads.
2Object-affected harmful factors
If flow separation is allowed to occur, then aerodynamic losses increase, but convective heat loads are reduced
Solution Approach 1:
The hump feature provides localized flow control exactly where separation initiates. By modifying the leading edge geometry locally, the flow attachment is improved without requiring changes to the entire airfoil section, thus preventing the trade-off between reducing heat loads and accepting aerodynamic losses.
3Object-affected harmful factors
If hump feature is added to airfoil assembly, then flow separation is reduced, but device complexity increases
Solution Approach 1:
The hump feature is implemented as a discrete, modular element that can be independently manufactured and then assembled to the airfoil. This segmentation allows the complex flow control function to be achieved through a simple, isolated geometric feature rather than a complex overall airfoil redesign, minimizing the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hump feature effectively reduces aerodynamic losses and convective heat loads by minimizing flow separation, thereby improving the overall performance of airfoil arrays, particularly those with low camber angles.
Implementation Method 1
air approaching the fluid flow passages can separate from portions of the arrays. The separation within the engine can disadvantageously increase aerodynamic losses and can contribute to locally increased convective heat loads.
Implementation Method 2
Air within the engine moves through fluid flow passages in the arrays. The fluid flow passages are established by adjacent airfoils projecting from laterally extending endwalls.
Implementation Method 3
The separation within the engine can disadvantageously increase aerodynamic losses and can contribute to locally increased convective heat loads.
Data Source
Figure 1~4
Figure 2~3
Figure 5~6
AI summary
An example airfoil assembly includes a base (60) having an airfoil (54) projecting radially therefrom. The base (60) extends laterally away from the airfoil (54). The airfoil (54) extends axially from an airfoil leading edge portion (62) to an airfoil trailing edge portion (66). The base (60) has a humped area (74) forward the airfoil leading edge portion (62).