Acoustically Enhanced Ejector System for Pulse Combustors
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Solution Overview
Problem
Existing pulse combustors are limited in efficiency, durability, and thrust output, with a need to enhance their performance beyond typical pulse mode combustion.
Innovation Solution
The implementation of an ejector system with supersonic fluid injection nozzles and resonant tubes, where the first resonant tube has a fundamental resonance frequency excitable by the nozzle, and a second resonant tube with a sub-harmonic frequency, along with an intake system that uses acoustic frequencies to enhance fluid entrainment and combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulse combustors operate in typical pulse mode combustion, then the combustion process is simple and reliable, but the efficiency, durability and thrust output are limited
Solution Approach 1:
The patent applies acoustic resonance and vibration principles by introducing resonant tubes with specific fundamental resonance frequencies. The first resonant tube has a fundamental resonance frequency excitable by the supersonic nozzle injection, and the second resonant tube has a sub-harmonic frequency, creating acoustic standing waves that enhance fluid entrainment and combustion efficiency, thereby increasing thrust output through vibrational energy.
Solution Approach 2:
The patent implements periodic action through the pulsating combustion mode where fuel and air periodically enter the combustion chamber. The supersonic fluid injection nozzle operates with acoustic injection frequency and amplitude, creating periodic pressure waves that drive the resonant tubes and enhance the combustion process, leading to improved efficiency and thrust output.
2Productivity
If supersonic fluid injection is used to excite resonant tubes, then fluid entrainment and combustion efficiency are enhanced, but the system complexity and manufacturing difficulty increase
Solution Approach 1:
The ejector system is segmented into distinct functional components: a supersonic fluid injection nozzle, a first resonant tube with a specific fundamental resonance frequency, and a second resonant tube with a sub-harmonic frequency. This segmentation allows each component to be designed and manufactured independently with optimized parameters, reducing overall manufacturing difficulty while maintaining enhanced combustion efficiency.
Solution Approach 2:
The patent utilizes parameter changes by selecting specific resonance frequencies for the resonant tubes relative to the supersonic nozzle injection frequency. The first resonant tube is designed with a fundamental resonance frequency that is a harmonic of the second resonant tube's sub-harmonic frequency, creating a tuned acoustic system that enhances fluid entrainment and combustion efficiency through resonant amplification.
3Quantity of substance
If resonant tubes with harmonic frequencies are used, then acoustic excitation and fluid entrainment are improved, but the device complexity increases
Solution Approach 1:
The patent merges the functions of multiple resonant tubes into a unified acoustic system where the first resonant tube and second resonant tube work together with their harmonic frequency relationship. The supersonic fluid injection nozzle simultaneously excites both resonant tubes, creating a combined acoustic field that enhances ambient fluid entrainment more effectively than individual tubes could achieve separately.
Solution Approach 2:
The resonant tube configuration serves multiple functions: the first resonant tube with its fundamental resonance frequency enhances fluid entrainment, while the second resonant tube with sub-harmonic frequency provides additional acoustic amplification. This multi-functional resonant system also contributes to stabilizing the combustion process and increasing thrust output, reducing the need for separate components for each function.
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 configuration increases the efficiency and thrust output of pulse combustors by effectively entraining ambient fluids, driving the resonant tubes into resonance, and optimizing the combustion process through acoustic excitation, leading to improved power output and durability.
Implementation Method 1
a supersonic fluid injection nozzle having an acoustic injection frequency and amplitude; a first resonant tube having a first fundamental resonance frequency excitable by the nozzle injection
Implementation Method 2
the first resonant tube having a first fundamental resonance frequency excitable by the nozzle injection; and a second resonant tube having a second fundamental resonance frequency being a sub-harmonic of the first fundamental resonance frequency
Implementation Method 3
a supersonic fluid injection nozzle having an acoustic injection frequency and amplitude; a first resonant tube having an inlet coupled to the nozzle for receiving the injected fluid from the nozzle and ambient fluid entrained by the injected fluid
Data Source
AI summary
The present specification generally relates to improvements to combustors such as burners and engines. In one aspect, the specification presents an acoustically enhanced ejector system which can be used as part of an intake system for a combustor. In another aspect, the specification teaches the use of a combustor combustion chamber as an oscillator to magnify a harmonic frequency of a pulsating frequency of the combustor. In still other aspects, the specification presents a combustion chamber having an inlet with a plurality of tangentially spaced apertures, and an in-line intake system connected to the apertures.