음향 가진된 프로판 제트 확산화염의 거동에 대한 실험적 연구 = (An) Experimental study on the flame behavior in Tone-excited propane jet diffusion flame

다국어 초록 (Multilingual Abstract)

Part II
A visualization study on the effect of the forcing strength in tone-excited jet diffusion flames has been conducted. Visualization techniques are employed using the Schlieren technique, ICCD and 35mm still camera. A flame stability curve is acquired according to mean velocity at the nozzle exit and forcing strength at a fuel tube resonance frequency. The flame behavior is globally grouped into two regimes from attached flame to blow-out flame according to the forcing strength; one sticks the traditional flame behavior which has been observed in general jet diffusion flames and the other shows various flame modes such as the flame under a feeble forcing where traditionally well-organized vortex motion evolves, a fat flame, an elongated flame, and an in-burning flame. Particular attention is focused on an elongation flame which is associated with a turnabout phenomenon of the vortex motion, and on a reversal of the direction of the vortex roll-up. It is found that the flame length with the forcing strength have relation to the evolution process of the inner flow structure. Especially the negative part of the acoustic cycle under the influence of a strong negative pressure gradient changes the shapes of the fuel stem and fuel branch part, and even dramatically the direction of vortex roll-up.
Part II
An experimental study on the flame lift-off characteristics of a propane jet flame highly diluted with nitrogen has been conducted by introducing the acoustic forcing at a tube resonance frequency. A flame stability curve is obtained by varying the forcing strength and the nozzle exit velocity for N_(2)-diluted flames. The flame lift-off behavior with the forcing strength and the nozzle exit velocity is globally categorized into three regimes; 1) a premixed flame behavior caused by the collapsible mixing for the large forcing strength, 2) a coexistent behavior of the well-premixed and edge flames interacting with well-organized inner fuel vortices for moderate forcing strength, and 3) edge flame behavior for small forcing strength. The coexistent behavior of the flame base in a lifted flame is specially focused to investigate since it may have a hint that the flame base behaves like a well-mixed premixed flame at a certain condition in highly turbulent lifted flames. The acoustic forcing to a self-pulsating laminar lifted flame affects the flame lift-off behavior considerably which is closely related to the downstream flow velocity, the mixture strength, the effective Lewis number for a fuel, and the flame stretch.

목차 (Table of Contents)

• 목차 = i
• Abstract = v
• List of Figures = vi
• Part I . 음향 가진된 비예혼합제트확산화염의 거동에 관한 가시화 연구
• I. 서론 = 1
• 1. 연구 배경 및 목적 = 1
• II. 실험장치 및 실험방법 = 4
• 1. 실험장치 = 4
• 2. 실험방법 = 7
• 2.1 유량검정 = 7
• 2.2 가진장치 및 연료관 공명 주파수 선정 = 12
• 2.3 속도측정 = 14
• 2.3.1 가진 강도(forcing strength)의 정의 = 14
• 2.3.2 열선유속계를 이용한 분류의 변동속도 측정 = 15
• 2.4 가시화 실험방법 = 19
• III. 실험결과 및 고찰 = 21
• 1. 연료관 공명 주파수로 가진된 분류의 특성 = 21
• 2. 화염 안정화선도 = 25
• 2.1 화염 안정화선도의 의미 = 25
• 2.2 작성방법 및 조건 = 25
• 2.3 가진된 분류 확산화염의 안정화선도 = 26
• 3. 화염길이 측정 = 30
• 3.1 화염길이의 의미 = 30
• 3.2 측정방법 및 조건 = 31
• 3.3 가진된 분류 확산화염의 길이 = 31
• 4. 가진된 분류 확산 화염의 내부 연료구조 = 35
• 4.1 쉴리렌 장치를 이용한 화염 내부 연료구조 가시화 = 35
• 4.2 실험방법 = 35
• 4.3 가진된 분류 확산화염의 내부 연료구조 = 36
• IV. 결론 = 45
• 참고문헌 = 46
• Part II. 음향 가진된 프로판 확산 화염의 부상 거동에 관한 실험적 연구 = 48
• Abstract = 49
• I. 서론 = 50
• 1. 연구 배경 및 목적 = 50
• II. 실험장치 및 실험방법 = 53
• 1. 실험장치 = 53
• 2. 실험방법 = 56
• 2.1 열선유속계를 이용한 변동 속도 측정 = 56
• 2.2 가스 크로마토그래프(gas chromatograph, GC)를 이용한 농도측정 = 57
• 2.2.1 샘플링 유로계 = 58
• III. 실험결과 및 고찰 = 65
• 1. 가진된 분류에서 나타나는 부상 화염들 = 65
• 2. 화염 안정화선도 = 68
• 3. 부상높이 측정 및 쉴리렌 가시화. = 72
• 4. 가스 크로마토그래프를 이용한 농도측정 = 85
• V. 결론 = 88
• 참고문헌 = 90
• 부록A. 열선유속계의 검정 = 94
• 부록B. 가스크로마토그래프의 원리 및 분석 방법 = 99