Compressor Flowpath Slope Angle Optimization
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Solution Overview
Problem
Existing low pressure compressor flowpath designs in gas turbine engines become non-optimal when the number of compressor stages is reduced and rotational speed is increased, leading to decreased performance.
Innovation Solution
A compressor section with a low pressure compressor having a plurality of rotor blades, a high pressure compressor with more stages, and a core flowpath with an outer diameter that slopes between 10 degrees and 15 degrees relative to the axis, along with features like variable vanes and a low pressure bleed, to improve airflow stability and compression efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of compressor stages is reduced and rotational speed is increased, then the compressor can operate at higher speeds with fewer stages, but existing flowpath designs become non-optimal and performance decreases
Solution Approach 1:
The patent applies parameter changes by modifying the flowpath geometry parameters, specifically setting the outer diameter slope angle between 10-15 degrees and the inner diameter slope angle between 5-10 degrees. These parameter adjustments optimize the flowpath for high-speed operation with reduced compressor stages, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent introduces dimensional changes by creating a tapered flowpath structure with different slope angles in different radial dimensions. The outer diameter has a steeper slope (10-15 degrees) compared to the inner diameter slope (5-10 degrees), adding geometric complexity to optimize airflow patterns at high rotational speeds.
2Speed
If the outer diameter slope angle is increased, then the flowpath can accommodate higher rotational speeds, but flow separation increases and performance decreases
Solution Approach 1:
The patent optimizes the outer diameter slope angle parameter to a specific range of 10-15 degrees, which balances the ability to accommodate high rotational speeds while minimizing flow separation. This precise parameter control resolves the contradiction between speed and harmful flow separation effects.
Solution Approach 2:
The patent applies local quality by differentiating the slope angles between the outer diameter (10-15 degrees) and inner diameter (5-10 degrees) regions. This localized geometric optimization ensures that each region of the flowpath is designed with appropriate characteristics for its specific functional requirements, reducing overall flow separation.
3Device complexity
If the inner diameter of the core flowpath is kept constant, then the structure is simpler, but compression efficiency decreases at higher speeds
Solution Approach 1:
The patent modifies the inner diameter parameter by introducing a controlled slope angle of 5-10 degrees, which optimizes compression efficiency at high speeds. This parameter change maintains reasonable structural complexity while significantly improving reliability through enhanced airflow control and compression performance.
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 solution enhances airflow stability, minimizes flow separation, and improves compression efficiency by maintaining a low slope angle for the outer diameter and incorporating features like variable vanes and a low pressure bleed, resulting in improved performance and reduced thrust specific fuel consumption.
Implementation Method 1
the slope angle is between 10 degrees and 15 degrees relative to the axis... minimizes flow separation
Data Source
AI summary
A gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor section including a propulsor that delivers flow to a core flowpath and a compressor section including first and second compressors. The core flowpath passes through the first compressor. The core flowpath in the first compressor has an outer diameter relative to the engine longitudinal axis. The outer diameter has a slope angle relative to the axis.