3차원 유한요소법을 이용한 가스터빈 연소기에서의 연소불안정 모델링
- 저자식별ID ORCID:https
- 발행기관 강릉원주대학교 일반대학원
- 발행년도 2021
- 학위수여년월 2022. 2
- 학위명 석사
- 학과 및 전공 도움말 일반대학원 정밀기계공학과
- 실제URI http://www.dcollection.net/handler/kangnung/000000011123
- UCI I804:42001-000000011123
- 본문언어 한국어
초록/요약 도움말
Recently, environmental pollution problems have become serious, and emission gas regulations are being strengthened in the gas turbine field. As an alternative to this, a lean premixed combustion method is proposed, but there is a problem that it generates combustion instability. In this study, we used the Acoustics module in COMSOL Multiphysics, a commercial code based on 3D finite element method for combustion instability modeling. In addition, the effects of major variables of the flame transfer function on the combustion instability generation characteristics were analyzed. First, acoustic field analysis in an annular combustor was conducted to analyze acoustic characteristics generated in an annular structure. The thermoacoustics analysis was conducted through frequency and growth rate, which are the main analysis results of combustion instability. The change of the gain and time delay, which are the variables of the flame transfer function, was not affected by the circumferential mode. But there was a great influence on the longitudinal mode. Next, the effects of combustion instability on hydrogen combustion system were analyzed. the geometry of the combustion system with complex structure was simplified. In addition, the acoustic field analysis was conducted according to the boundary conditions of the plenum inlet, and the boundary conditions setting according to the geometry simplification was concluded to be a very important acoustic factor. In the thermoacoustic analysis, it was found that the flame surface location becomes shorter as the hydrogen combustion increases through the hydrogen combustion characteristics, which means that the time delay becomes smaller and smaller. Therefore, the effects of combustion instability on gain and time delay were investigated and it was concluded that it is related to hydrogen combustion characteristics. In addition, the frequency and growth rate were affected by gain and time delay in hydrogen combustion system. Also, the combustion instability modeling was validated because it was confirmed that the analysis results tend to be somewhat consistent with the experimental data.
more목차 도움말
1. 서 론 ···································································································································· 1
1.1 연구 배경 ············································································································· 1
1.2 연소불안정 ··········································································································· 3
1.3 Rayleigh criterion ···························································································· 4
1.4 연소불안정 모델링 ···························································································· 5
1.5 연구 동향 ············································································································· 6
1.6 연구 목적 ············································································································· 7
2. 연구 방법 ···························································································································· 8
2.1 지배방정식 ··········································································································· 8
2.2 음향 경계조건 ····································································································· 9
2.3 화염전달함수 ····································································································· 10
3. 해석 대상 연소기 및 해석 조건 ················································································ 13
3.1 해석 대상 연소기 A ······················································································· 13
3.1.1 해석 형상 모델링 ················································································· 13
3.1.2 해석 조건 ·································································································· 15
3.1.3 화염전달함수 모델링 ············································································· 19
3.2 해석 대상 연소기 B ························································································· 20
3.2.1 해석 형상 모델링 ··················································································· 20
3.2.2 해석 조건 ·································································································· 24
3.2.3 실험 데이터 분석 ··················································································· 24
3.2.4 화염전달함수 모델링 ············································································· 26
4. 해석 결과 및 고찰 ··········································································································· 29
4.1 해석 대상 연소기 A ························································································· 29
4.1.1 음향 해석 결과 ······················································································· 29
4.1.2 열 음향 해석 결과 ················································································· 30
4.2 해석 대상 연소기 B ························································································· 34
4.2.1 음향 해석 결과 ······················································································· 34
4.2.2 열 음향 해석 결과 ················································································· 35
4.2.3 실험 주파수와의 비교 ··········································································· 40
4.2.4 실험 동압 데이터와의 비교 ································································ 41
5. 결론 ······································································································································ 43
