Micro-Vortex Generator Nozzle Seals for Jet Engine Noise Reduction
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Solution Overview
Problem
Existing methods for reducing jet engine noise, such as corrugated engine seals, chevrons, fluidic injection, and fluidic inserts, are either costly, require significant design changes, or are not durable and cost-effective for retrofitting existing engines, posing safety risks for ground personnel due to high noise levels during takeoff.
Innovation Solution
The implementation of a nozzle apparatus with interconnected seals and micro-vortex generator pairs that generate vortices to modify shock cell formation and reduce noise, which can be retrofitted to existing engines and integrated into new ones without the need for additional fluid supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If corrugated engine seals are used to reduce engine noise, then noise reduction is achieved, but device complexity and manufacturing cost increase substantially
Solution Approach 1:
The patent applies local quality by placing micro-vortex generators only at specific locations on the nozzle seal surfaces where they are most effective for noise reduction, rather than redesigning the entire nozzle structure. This localized approach reduces complexity compared to corrugated seals while maintaining noise reduction benefits.
Solution Approach 2:
The patent changes the physical parameters of the nozzle by adding small vortex-generating elements that modify flow characteristics locally. This parameter change approach (adding vortex generators) achieves noise reduction without the substantial structural changes required by corrugated seals.
2Object-affected harmful factors
If chevrons are attached to the nozzle lip surface to reduce engine noise, then noise reduction is achieved, but reliability and durability are insufficient for production aircraft
Solution Approach 1:
The patent segments the noise reduction function into multiple small micro-vortex generators distributed across the seal surfaces, rather than using large attached chevrons at the lip. This segmentation creates a more distributed and reliable system that is less prone to failure from individual element damage.
Solution Approach 2:
The micro-vortex generators are simple, small-scale elements that can be easily replaced or maintained, making the system more reliable and suitable for production aircraft compared to complex chevron attachments.
3Object-affected harmful factors
If fluidic injection or fluidic insert approaches are used to reduce engine noise, then noise reduction is achieved, but device complexity and cost increase due to additional fluid supply requirements
Solution Approach 1:
The patent extracts the noise reduction function from complex fluidic systems and implements it through passive micro-vortex generators on the nozzle surfaces. This removes the need for additional fluid supply systems while maintaining noise reduction effectiveness.
Solution Approach 2:
The micro-vortex generators are passive elements that utilize the existing engine exhaust flow to generate vortices and reduce noise, without requiring external fluid supplies or active control systems. The system serves itself using the available flow.
4Ease of manufacture
If existing nozzle designs are used, then manufacturing cost is reduced, but engine noise levels remain high creating safety risks for ground personnel
Solution Approach 1:
The micro-vortex generators are installed on the nozzle surfaces during manufacturing or as a retrofit, preparing the nozzle for noise reduction before the engine operates. This preliminary modification maintains manufacturing efficiency while enabling noise reduction.
Solution Approach 2:
The patent applies local quality by adding noise reduction elements only where needed on the nozzle surfaces, rather than redesigning the entire nozzle. This localized modification maintains manufacturing simplicity while achieving noise reduction.
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 solution effectively reduces engine noise by weakening shock-cell structures and stabilizing boundary layers, leading to lower noise levels during takeoff, thus enhancing safety and reducing the risk of hearing damage for ground personnel.
Implementation Method 1
A plurality of micro-vortex generator pairs are provided on a plurality of seal surfaces of the nozzle section, respectively. Each of the plurality of micro-vortex generator pairs is constructed to generate two vortices adjacent to an interior surface of the nozzle section and extending in a direction towards a nozzle exit.
Implementation Method 2
The vortices generated by the plurality of micro-vortex generator pairs modify shock cell formation within the nozzle section.
Data Source
AI summary
Methods and apparatuses for reducing engine noise provided. In one embodiment, an apparatus is provided that includes a plurality of seals and flaps that are interconnected and circumferentially arranged. Also included are a plurality of micro-vortex generator pairs respectively disposed in a circumferential manner on an interior surface of the seals. Each micro-vortex generator pair includes a first and second micro-vortex generator. In another embodiment, a method of generating a plurality of vortices in a nozzle section of a jet engine is provided. A plurality of micro-vortex generator pairs are provided on a plurality of seal surfaces of the nozzle section, respectively. The micro-vortex generator pairs are constructed to generate two vortices adjacent to an interior surface of the nozzle section and extending in a direction towards a nozzle exit. The interaction between the nozzle flow and the micro-vortex generator pairs greatly modify the shock cell structure within the nozzle section and the turbulence structure in the jet plume.