Dual-Mode Plug Nozzle Independent Throat Control
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Solution Overview
Problem
Existing gas turbine engine nozzles face performance degradation due to fixed geometry, which fails to efficiently manage a wide range of nozzle pressure ratios, leading to suboptimal performance across various flight conditions, and previous variable geometry solutions suffer from complexity, leakage issues, and inadequate control over throat area and area ratio.
Innovation Solution
A nozzle design featuring a centerbody and shrouds that allow independent translation to vary the throat and exit areas, enabling precise control of the area ratio through the use of actuators, reducing complexity and leakage while accommodating a wide range of pressure ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed geometry nozzle is used, then the structure is simple, but the nozzle performance degrades across a wide range of pressure ratios
Solution Approach 1:
The patent implements a variable geometry nozzle where the throat area can be dynamically adjusted using a movable centerbody or plug. This dynamic adjustment capability allows the nozzle to adapt to different pressure ratios and flight conditions, resolving the contradiction between structural simplicity and performance reliability across varying operating conditions.
2Adaptability or versatility
If overlapping flaps and seals are used to control throat area, then the throat area can be adjusted, but leakage paths are created that reduce operating efficiency
Solution Approach 1:
The patent removes the overlapping flaps and seals from the nozzle design and replaces them with a movable centerbody or plug that translates axially to control the throat area. This extraction of the problematic sealing mechanism eliminates the leakage paths while maintaining the ability to adjust the throat area, thus resolving the contradiction between adaptability and energy efficiency.
3Device complexity
If the A9/A8 area ratio is kinematically linked to A8, then the nozzle structure is constrained, but the A9/A8 schedule cannot be optimally matched to engine cycle demands
Solution Approach 1:
The patent segments the control of throat area (A8) and exit area (A9) into independent functions. The movable centerbody controls A8 independently, while the exit area A9 can be controlled separately through the outer nozzle geometry. This segmentation allows the A9/A8 area ratio schedule to be independently optimized for specific engine cycles without being constrained by kinematic linkages, resolving the contradiction between structural complexity and scheduling adaptability.
Data Source
AI summary
A method for controlling flow through an exhaust nozzle includes: providing a centerbody including a maximum diameter section; providing an inner shroud surrounding the centerbody, including at least a middle section of decreased diameter and terminating at an aft edge; providing an outer shroud. wherein the centerbody and the inner shroud collectively define a throat, and the outer shroud and the centerbody collectively define an exit; selectively translating the inner shroud and outer shroud to vary the throat; and selectively translating the outer shroud to vary the ratio of the exit to the throat; wherein, when the inner shroud is in a forward position, its aft edge is forward of the maximum diameter section of the centerbody, such that the throat of the nozzle is formed between the aft edge of the inner shroud and the centerbody.