Geared Turbofan Variable Guide Vanes for Compressor Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face challenges in achieving optimal thermal, transfer, and propulsive efficiencies, particularly in maintaining mechanical simplicity while achieving high overall pressure ratios and power density.
Innovation Solution
A geared architecture is implemented with a unique pressure split between low and high compressors, utilizing multiple stages of variable guide vanes to control airflow and reduce mechanical shaft speed, coupled with a high-bypass geared aircraft engine design that includes an epicyclical gear train for efficient power transfer and reduced structural requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a geared architecture is implemented with multiple compressor stages to achieve high overall pressure ratios, then thermal efficiency and power density are improved, but device complexity increases due to additional mechanical components and shaft speed reduction mechanisms
Solution Approach 1:
The compressor section is divided into multiple independent compressor stages (first compressor and second compressor) with separate variable guide vane systems. This segmentation allows each compressor stage to be optimized independently for specific pressure ratios while maintaining overall high efficiency, resolving the contradiction by breaking down the complex high-pressure-ratio requirement into manageable stages.
Solution Approach 2:
Variable guide vanes are implemented in both the first and second compressors, allowing dynamic adjustment of airflow angles and pressure ratios based on operating conditions. This dynamic control enables the system to maintain optimal thermal efficiency across varying flight conditions while managing the complexity through adaptive rather than static design.
2Ease of operation
If variable guide vanes are added to control compressor operation, then operability and efficiency are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The variable guide vane system is segmented into multiple independent sets (first variable guide vane for the first compressor, second variable guide vane for the second compressor). Each set can be manufactured and tested independently, simplifying the manufacturing process compared to a single complex integrated system, while still achieving improved compressor operability through coordinated control.
Solution Approach 2:
The variable guide vanes enable change in airflow parameters (angle, pressure, flow rate) to optimize compressor operation across different operating conditions. This parameter control improves ease of operation by allowing the compressor to adapt to varying demands, while the modular nature of the parameter control systems keeps manufacturing complexity manageable.
3Use of energy by moving object
If a high-bypass geared aircraft engine design is used with epicyclical gear train, then propulsive efficiency is improved, but weight and structural complexity increase
Solution Approach 1:
The epicyclical gear train merges the power output from multiple turbine stages into a single shaft that drives the fan. This merging of power streams achieves the desired propulsive efficiency by coordinating the work output of different turbine-compressor pairs, while the compact epicyclical design minimizes the weight penalty compared to alternative gear arrangements.
Solution Approach 2:
The epicyclical gear train employs a nested structure where planet gears are positioned around a sun gear, with carrier components housing the entire assembly. This nested configuration achieves high gear reduction ratios in a compact volume, improving propulsive efficiency while minimizing the weight increase that would result from larger, simpler gear arrangements.
4Use of energy by moving object
If pressure ratio is increased in compressor stages, then overall pressure ratio and thermal efficiency are improved, but mechanical stress and structural requirements increase
Solution Approach 1:
The total pressure ratio requirement is segmented across multiple compressor stages rather than concentrated in a single stage. The first compressor and second compressor each handle portions of the overall pressure ratio, reducing the mechanical stress on individual compressor components while achieving the same overall thermal efficiency improvement that would require high pressure ratios.
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 configuration enables high overall pressure ratios with improved thermal efficiency, reduced mechanical complexity, and a 2% fuel burn reduction by optimizing the work split between low and high-pressure compressors and turbines, while maintaining compactness and power density.
Implementation Method 1
At least one first variable guide vane controls operation of the first compressor and at least one second variable guide vane controls operation of the second compressor
Implementation Method 2
Air entering the compressor section is compressed and delivered into the combustion section
Implementation Method 3
The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section
Implementation Method 4
turbine section includes low and high pressure turbines
Implementation Method 5
Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow
Implementation Method 6
A speed reduction device such as an epicyclical gear assembly may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section
Data Source
AI summary
A gas turbine engine includes a propulsor having a plurality of blades, a compressor section including a first compressor and a second compressor aft of the first compressor. The first compressor includes at least one array of first variable guide vanes that control operation of the first compressor. The second compressor includes at least one array of second variable guide vanes that control operation of the second compressor. A turbine section includes a first turbine and a second turbine. A geared architecture is driven by the second turbine for rotating the propulsor.