Asymmetric Nozzle Guide Vanes for Gas Turbine Temperature Control
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Solution Overview
Problem
Gas turbine engines face challenges in achieving increased aerodynamic and thermodynamic efficiency due to high vibratory responses from multiple engine order crossings, which cannot be designed out, requiring a change in driving frequency and forces, and result in increased gas temperature variability and potential hot spots, affecting engine thermal efficiency.
Innovation Solution
The implementation of an asymmetric stator vane configuration in front of the turbine blade row, along with an asymmetric arrangement of Nozzle Guide Vanes (NGVs) and fuel nozzles, to alter driving frequencies and forces, and maintain optimal alignment for efficient airflow diffusion, reducing gas temperature variations and downstream hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If symmetric nozzle guide vanes are used, then manufacturing and assembly are simplified, but gas temperature variability increases and hot spots occur
Solution Approach 1:
The patent applies asymmetry by configuring the nozzle guide vanes with different geometric parameters on opposite sides of the combustion chamber. Specifically, the vanes have different inlet angles, outlet angles, or curvature radii depending on their position relative to the fuel nozzles. This asymmetric configuration compensates for the non-uniform temperature distribution caused by discrete fuel injection points, thereby reducing gas temperature variability and eliminating hot spots while maintaining manufacturing feasibility through standardized vane designs.
2Temperature
If asymmetric nozzle guide vanes are implemented, then gas temperature variability is reduced, but device complexity increases
Solution Approach 1:
The patent implements local quality by applying geometric modifications to specific portions of the nozzle guide vanes based on their location within the combustion chamber. Rather than making all vanes completely different, only certain geometric parameters (such as inlet angle or curvature) are adjusted locally for vanes positioned near fuel nozzles, while other vanes maintain standard geometry. This approach achieves temperature uniformity with minimal increase in overall device complexity.
3Reliability
If turbine blade design is modified to reduce vibratory responses, then blade reliability improves, but aerodynamic efficiency may be compromised
Solution Approach 1:
The patent introduces asymmetric nozzle guide vanes as an intermediary element between the combustion process and the turbine blades. These vanes modify the flow characteristics and reduce unsteady forcing on the turbine blades, thereby reducing vibratory responses and improving reliability. By placing the modification in the upstream flow field rather than on the blades themselves, the aerodynamic efficiency of the blades is preserved while still achieving the desired reduction in vibratory responses.
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 reduces downstream gas temperature variations, minimizing the impact on static gaspath hardware and improving thermal efficiency by maintaining a consistent alignment between fuel nozzles and NGVs, thereby reducing the need for additional cooling air and enhancing engine performance.
Implementation Method 1
maintaining a consistent alignment between fuel nozzles and NGVs, thereby reducing the need for additional cooling air and enhancing engine performance
Data Source
AI summary
A gas turbine engine includes a multiple of Nozzle Guide Vanes (NGVs) arranged asymmetrically and a multiple of NGVs clocked with respect to the multiple of fuel nozzles around a 360 degree circumference.