Supersonic Exhaust Nozzle Using Ejector for Noise Reduction
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Solution Overview
Problem
Existing gas turbine engine systems face challenges in reducing noise output during subsonic and low-speed operations while maintaining effective thrust in various flight regimes, particularly in reducing exhaust stream velocity and noise generation.
Innovation Solution
A variable cycle gas turbine engine system with an adaptive fan and a supersonic converging-diverging exhaust nozzle system that includes a mixer and an ejector with variable-position doors to entrain ambient air, allowing for selective reduction of exhaust stream velocity and noise reduction by varying the divergence angle of the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If exhaust stream velocity is reduced to lower noise output during subsonic operations, then noise generation is reduced, but thrust capability deteriorates
Solution Approach 1:
The patent introduces an ejector as an intermediary device between the exhaust stream and ambient air. The ejector creates a mixing region where high-velocity exhaust gases interact with ambient air, gradually decelerating the exhaust stream through momentum exchange and mixing, thereby reducing noise while preserving thrust through the induced flow field
Solution Approach 2:
The patent utilizes pneumatic principles by employing the ejector to create a low-pressure region that draws ambient air into the exhaust stream. This pneumatic mixing process allows for smooth momentum transfer from the high-velocity exhaust to the ambient air, reducing exhaust velocity and noise while maintaining thrust through the combined flow field
2Device complexity
If a fixed nozzle configuration is used, then device complexity is reduced, but adaptability to different flight regimes deteriorates
Solution Approach 1:
The patent implements a variable geometry nozzle system with movable walls that can dynamically adjust the nozzle expansion angle based on flight conditions. The nozzle transitions from a converging configuration at low speeds to a converging-diverging supersonic configuration at high speeds, providing adaptability across all flight regimes while maintaining manageable complexity through a single movable component
Solution Approach 2:
The patent creates a universal nozzle system that performs multiple functions through a single variable geometry design. The same nozzle structure handles subsonic, transonic, and supersonic flow regimes by adjusting its geometry, eliminating the need for separate nozzles for different flight conditions and reducing overall device complexity
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
The system effectively reduces noise during low-speed operations by entraining ambient air into the exhaust stream, while maintaining thrust capabilities across subsonic, transonic, and supersonic flight regimes through the adaptive nozzle configuration.
Implementation Method 1
an ejector configured to entrain ambient free stream air into the third stream flow
Implementation Method 2
a mixer configured to mix the first stream flow and the second stream flow
Implementation Method 3
a supersonic converging-diverging exhaust nozzle system
Data Source
AI summary
One embodiment of the present invention is a unique gas turbine engine system. Another embodiment is a unique exhaust nozzle system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engine systems and exhaust nozzle systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.