Gas Turbine Compressor Blade Leading Edge Sweep Angle Variation
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Solution Overview
Problem
High-pressure compressors in gas turbines, such as aircraft engines, face mechanical stresses and inefficient flow conditions due to increased circumferential velocities and reduced number of stages, requiring an optimized aerodynamic design of rotating blades to manage shock waves effectively.
Innovation Solution
The leading edges of rotating blades are designed with a sweep angle that changes with height, featuring a forward sweep angle in the radially external area, a backward sweep angle or zero sweep angle adjacent to it, and another forward sweep angle adjacent to the backward sweep angle, optimizing the position of the shock wave relative to the leading edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of compressor stages is reduced to lower manufacturing costs, then device complexity is reduced, but circumferential velocities increase causing higher mechanical stresses and supersonic flow conditions
Solution Approach 1:
The leading edge of the rotating blades is designed with spatially varying sweep angles (forward sweep in radially external area, backward sweep in intermediate area, forward sweep again in tip area) to locally optimize flow conditions. This local differentiation allows the blade to handle supersonic and transonic flow conditions at different radial positions, reducing mechanical stresses without requiring additional compressor stages.
2Productivity
If circumferential velocities are increased to achieve higher stage pressure ratios, then productivity is improved, but shock wave position becomes unstable reducing efficiency
Solution Approach 1:
The blade leading edge incorporates dynamic sweep angle variations that adapt to different flow conditions. The forward-sweep-backward-sweep-forward pattern creates a dynamic interaction with the shock wave, allowing the shock front to be positioned optimally on the blade surface during operation, thereby stabilizing shock wave position while maintaining high circumferential velocities for improved productivity.
3Ease of manufacture
If conventional uniform sweep angle design is used, then manufacturing is simplified, but aerodynamic efficiency is reduced due to suboptimal shock wave positioning
Solution Approach 1:
Instead of a uniform sweep angle, the blade leading edge features locally optimized sweep angle variations (forward-backward-forward pattern) that are tailored to the specific flow conditions at different radial positions. This local quality differentiation improves aerodynamic efficiency and shock wave positioning while remaining manufacturable using conventional blade fabrication processes.
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
This design enhances the aerodynamic compatibility of the compressor, improving efficiency, expanding the working range, optimizing surge limit margin, and reducing mechanical stresses by ensuring an optimal position of the shock wave, thus enhancing the overall performance of the compressor.
Implementation Method 1
the position of the shock front or shock wave of the compressor with regard to the leading edge of the rotating blades is important for providing optimum efficiency and an optimum working range of the compressor
Data Source
AI summary
A compressor, particularly a high-pressure compressor, of a gas turbine, particularly of an aircraft engine, includes at least one rotor and a number of blades (11, 12), which are assigned to the or to each rotor and which rotate together with the respective rotor. Each blade (11, 12) is delimited, in essence, by a flow entry edge or leading edge (16), a flow exit edge or trailing edge (17), and by a blade surface (20), which extends between the leading edge (16) and the trailing edge (17) while forming a suction side (18) and a pressure side. The leading edges (16) of the blades (11, 12) are slanted at a sweep angle that changes with the height of the respective blade (11, 12) in such a manner that the leading edges (16) comprise, in a radially external area (23) of the same, at least one forward sweep angle, a backward sweep angle or zero-sweep angle following in a radially external manner, and a forward sweep angle following, in a radially external manner, the backward sweep angle or the zero-sweep angle.