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로켓 엔진 연소기에서 기체-액체형 분사기의 음향 감쇠 특성에 관한 실험적 연구

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Author(s)
김학순
Issued Date
2007
Abstract
In a liquid rocket engine, the role of gas-liquid scheme injector as an acoustic resonator or absorber is studied experimentally for combustion stability by adopting linear acoustic test.
First, acoustic behavior in a rocket combustor with a single injector is investigated and the acoustic-damping effect of the injector is evaluated for cold condition by the quantitative parameter of damping factor as a function of injector length. From the experimental data, it is found that the injector can play a significant role in acoustic damping when it is tuned finely. The optimum tuning-length of the injector to maximize the damping capacity is near half of a full wavelength of the first longitudinal overtone mode traveling in the injector with the acoustic frequency intended for damping in the chamber. When the injector has large diameter, the phenomenon of the mode split is observed near the optimum injector length and thereby, the acoustic-damping effect of the tuned injectors can be degraded.
Second, acoustic-damping characteristics of multi-injectors are intensively investigated. From the experimental data, it is found that acoustic oscillations are almost damped out by multi-injectors when they have the tuning length. The length corresponds to a half wavelength of the first longitudinal overtone mode traveling inside the injector with the acoustic frequency intended for damping in the chamber. But, new injector-coupled acoustic modes show up in the chamber with the injectors of the tuning length although the target mode is nearly damped out. And, appreciable frequency shift is always observed except for the case of the worst tuned injector. Accordingly, it is proposed that the tuning length is adjusted to have the shorter length than a half wavelength when these phenomena are considered.
Alternative Title
Experimental Study of Acoustic Damping Induced by Gas-Liquid Scheme Injector in a Rocket Combustor
Affiliation
조선대학교 대학원
Department
일반대학원 항공우주공학과
Awarded Date
2007-02
Table Of Contents
목차 = i
LIST OF TABLE = iii
LIST OF FIGURE = iv
NOMENCLATURE = vii
ABSTRACT = viii
제1장 서론 = 1
제2장 가진 신호와 신호처리에 대한 고찰 = 4
2.1 연소실에 대한 고찰 = 4
2.2 음향학적 실험 방안 및 장치 = 6
2.2.1 상온음향실험장치 = 6
2.2.2 FFT 프로그램 및 음향센서 = 7
2.3 가진신호(random noise)에 대한 고찰 = 9
2.4 신호처리(signal conditioning)에 관한 고찰 = 11
2.4.1 주파수 분해능 = 11
2.4.2 신호의 평균처리(signal averaging) = 12
제3장 음향학적 고찰과 이론 = 15
3.1 분사기에 관한 음향학적 고찰 = 15
제4장 측정 및 결과 = 17
4.1 연소실 공진주파수의 이론적 특성 = 17
4.2 연소실 공진주파수의 실험적 특성 = 18
4.3 단일 분사기를 장착한 연소실의 음향응답 = 21
4.3.1 직경 7 mm인 분사기를 장착한 연소실 = 21
4.3.2 분사기의 열린 조건과 닫힌 조건과의 비교 = 23
4.3.3 14 mm & 2O mm 분사기의 음향학적 특성 = 25
4.3.4 동일한 열린 면적비를 가지는 분사기의 음향학적 특성 = 28
4.4 다수 분사기를 장착한 연소실의 음향응답 = 32
4.4.1 시험 장치 및 방안 = 32
4.4.2 PC(poly carbonate)를 사용한 단일분사기의 음향학적 특성 = 33
4.4.3 다수 분사기와 연소실의 상호작용에 의한 음향학적 특성 = 35
제5장 결론 = 41
참고 문헌 = 43
Degree
Master
Publisher
조선대학교
Citation
김학순. (2007). 로켓 엔진 연소기에서 기체-액체형 분사기의 음향 감쇠 특성에 관한 실험적 연구.
Type
Dissertation
URI
https://oak.chosun.ac.kr/handle/2020.oak/6800
http://chosun.dcollection.net/common/orgView/200000231703
Appears in Collections:
General Graduate School > 3. Theses(Master)
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