Swirler Vane Spanwise Chord Variation for Gas Turbine Combustor
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Solution Overview
Problem
Existing fuel nozzle designs for gas turbine combustors face challenges in achieving high efficiency, lean blowout characteristics, altitude relight, low smoke and pollutant output, long life, and low cost, particularly in optimizing the swirl angle distribution across the vanes of the swirler.
Innovation Solution
The design incorporates a swirler vane pack with spanwise changing sections, where each vane has a chord that decreases by 25%-75% from the first end to the second end, and a method to engineer the vane pack to achieve a target change in swirl angle, resulting in a tailored discharge profile with a peak swirl angle between 15° and 25° at 95%-100% of the exit radius, effectively producing a Rankine vortex.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vanes have a constant chord across the span, then the manufacturing is simpler, but the swirl angle distribution cannot be optimized for improved lean blowout characteristics and efficiency
Solution Approach 1:
The vane chord length varies locally across the span, with the inboard portion having a different chord length than the outboard portion. This local variation in geometry creates the desired swirl angle distribution without requiring complex three-dimensional twisting, thus improving lean blowout characteristics while maintaining manufacturing simplicity.
Solution Approach 2:
The chord length parameter of the vane is changed across the span to achieve the target swirl angle distribution. By varying this geometric parameter, the invention optimizes the flow characteristics and lean blowout performance without introducing excessive complexity into the overall vane design.
2Productivity
If the vanes have a spanwise distributed twist to achieve desired swirl angle distribution, then the combustor efficiency and lean blowout characteristics improve, but the manufacturing complexity and cost increase
Solution Approach 1:
Instead of applying a continuous twist across the entire vane span, the invention applies different chord lengths to specific spanwise regions (inboard vs. outboard portions). This localized geometric variation achieves the desired swirl angle distribution while maintaining simpler manufacturing compared to fully twisted vanes.
Solution Approach 2:
Rather than twisting the vane to change the swirl angle distribution, the invention inverts the approach by changing the chord length parameter. This alternative method achieves the same functional result (optimized swirl) through a different geometric parameter that is easier to manufacture.
3Productivity
If the vane chord decreases by 25%-75% from the first end to the second end, then a tailored discharge profile with peak swirl angle of 15°-25° at 95%-100% exit radius is achieved, but the vane structural strength may be reduced
Solution Approach 1:
The chord reduction is applied specifically to the outboard portion of the vane where it is needed to achieve the desired swirl angle distribution and discharge profile. The inboard portion maintains a larger chord length to preserve structural strength near the hub, thus balancing performance requirements with structural integrity.
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 enhances lean blowout characteristics and achieves a tailored swirl profile, improving the efficiency and performance of the gas turbine combustor while maintaining low pollutant output and cost-effectiveness.
Implementation Method 1
each vane having a section characterized by a spanwise change in section effective to change the swirl angle from the first end to the second end... effectively producing a Rankine vortex
Data Source
AI summary
A gas turbine engine combustor swirler has vanes with a spanwise chord length distribution providing a desired swirl distribution.