Sector Nozzle Vibration Resistance via Integrated Struts
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Solution Overview
Problem
Fuel nozzle assemblies in gas turbines face challenges with vibration and load stability, particularly during operation, as existing designs often require separate mounting components and may not effectively withstand the high-frequency vibrations generated by the turbine.
Innovation Solution
The sector nozzle assembly incorporates a shell and longitudinal struts designed to stabilize the nozzle against vibrations and loads, allowing for direct attachment to the combustor end cover without a separate nozzle cap, shifting the natural frequency of the nozzle beyond the third revolution of the gas turbine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate nozzle cap is used for mounting, then the nozzle can be attached to the combustor, but the device complexity increases and structural stability under vibration deteriorates
Solution Approach 1:
The mounting structure is merged with the nozzle body itself. The nozzle includes integrated mounting features (such as mounting lugs or flanges) that are formed as part of the nozzle structure, eliminating the need for separate mounting components. This integration reduces device complexity while maintaining or improving structural stability under vibration and load conditions.
2Reliability
If the natural frequency is shifted beyond the third revolution, then the nozzle can withstand vibrations at three times base frequency, but the manufacturing precision requirements increase
Solution Approach 1:
The natural frequency of the nozzle is modified by changing physical parameters such as wall thickness, material density, or structural geometry. By adjusting these parameters, the natural frequency is shifted to a value beyond three times the base operating frequency, allowing the nozzle to operate in an anti-resonance region where vibration amplitudes are minimized. This approach achieves vibration resistance through controlled parameter modification rather than requiring extremely tight manufacturing tolerances.
3Reliability
If the shell and struts are used to inhibit bending and twisting, then the structural stability improves, but the weight of the nozzle increases
Solution Approach 1:
Instead of uniformly reinforcing the entire nozzle structure, local quality enhancement is applied by adding stiffening elements (such as ribs, gussets, or localized thickening) only in specific regions where bending and twisting stresses are highest. This targeted reinforcement provides the necessary structural stability while minimizing the overall weight increase compared to uniform reinforcement throughout the entire nozzle.
Data Source
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AI summary
Systems are provided for mounting sector nozzles (34) within gas turbine combustors (12). In one embodiment, a sector nozzle (34) includes a nozzle portion (48) configured to mix fuel and air to produce a fuel-air mixture and a shell (56) coupled to the nozzle portion (48). The sector nozzle (34) also includes a first longitudinal strut (60) and a second longitudinal strut (60) coupled to a first surface (78) of the shell (56) on opposite sides of a window (67) within the first surface (78). A third longitudinal strut (62) is coupled to a second surface (84) of the shell, and the second surface (84) is disposed opposite of the first surface (78).