Multi-Stream Nozzle Supersonic Ejector Thrust Control
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Solution Overview
Problem
Existing aircraft engine exhaust nozzle systems face challenges in efficiently managing multiple varying flows, particularly in low and high power modes, leading to suboptimal performance and thrust efficiency.
Innovation Solution
A multi-stream aircraft fixed geometry nozzle design that merges a third stream from a bypass duct with a primary stream using a supersonic ejector, allowing for variable area ratio adjustments through a third stream pressure/area flow control device, enabling efficient thrust generation across different operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed geometry nozzle is used, then the device complexity is reduced, but the nozzle efficiency decreases across varying power modes
Solution Approach 1:
The patent applies dynamics by enabling the fixed geometry nozzle to operate efficiently across varying power modes through a third stream that dynamically adjusts the effective area ratio of the primary airstream. The third stream duct and flow control device allow the system to adapt its performance characteristics without changing the physical geometry of the nozzle, resolving the contradiction between fixed structure and variable efficiency.
2Productivity
If multiple varying flows are combined, then the thrust generation efficiency improves, but the device complexity increases
Solution Approach 1:
The patent merges multiple flows (primary stream from inner nozzle and third stream from outer nozzle) into a single exhaust pathway. This combining approach improves thrust generation efficiency by utilizing multiple varying flows simultaneously while maintaining a relatively simple fixed geometry structure, thus resolving the contradiction between productivity improvement and device complexity.
3Reliability
If the effective area ratio is varied, then the nozzle efficiency increases, but the device complexity increases
Solution Approach 1:
The patent changes the parameter of effective area ratio by introducing a third stream that mixes with the primary airstream. This allows the effective area ratio to be varied through flow rate adjustments of the third stream rather than through complex mechanical area adjustment mechanisms, thereby improving nozzle efficiency while limiting the increase in 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 solution achieves high nozzle efficiency by varying the effective area ratio of the primary airstream, allowing for efficient thrust generation across a broad range of power settings, from 100% to 60% thrust, while maintaining constant mass flow rates and reducing specific fuel consumption.
Implementation Method 1
an outer nozzle is configured to channel a third stream from an aft end of a third stream duct surrounding a bypass duct to a supersonic ejector, to merge the third stream with a primary stream of an inner nozzle
Data Source
AI summary
A multi stream aircraft fixed geometry nozzle includes an inner nozzle, an outer nozzle, and a supersonic ejector. The outer nozzle is configured to channel a third stream from an aft end of a third stream duct surrounding a bypass duct of a multi stream aircraft engine to the supersonic ejector to merge the third stream with the primary stream. The fixed geometry nozzle is configured to operate between an SFC mode and a thrust mode such that, when the inner nozzle accelerates the primary stream supersonically to the supersonic ejector, at which the primary stream is merged with the third stream, in the SFC mode the total pressure of the primary stream is substantially the same as the total pressure of the third stream, and in the thrust mode the total pressure of the primary stream is substantially greater than the total pressure of the third stream.