해석학적 방법을 통한 가스터빈 연소기에서 연소불안정 예측
Analytical approach for predicting combustion instability focusing on gas turbine combustor.
- 주제(키워드) 도움말 Gas turbine , Single nozzle combustors , Annular combustor , Thermo-acoustic model , Combustion instability , Mean flow effects , Hydrogen , , Flame dynamics
- 발행기관 강릉원주대학교 산업대학원
- 지도교수 도움말 Daesik Kim
- 발행년도 2024
- 학위수여년월 2024. 2
- 학위명 석사
- 학과 및 전공 도움말 산업대학원 기계공학과
- 세부분야 해당없음
- 실제URI http://www.dcollection.net/handler/kangnung/000000011654
- UCI I804:42001-000000011654
- 본문언어 영어
초록/요약 도움말
Lean and hydrogen combustion conditions in gas turbine combustors can lead to combustion instability (CI) sometime. CI is caused by the dynamic fluctuations that arise from the interaction between acoustic oscillations and heat release perturbations. This paper presents one-dimensional and low-order longitudinal acoustic models for single nozzle gas turbine combustors and annular gas turbine combustors, respectively. Analytical combustor models are derived from the so-called network approach. The validity of the analytical combustor models is established through verification with numerical simulations employing COMSOL Multiphysics (3D FEM solver of the Helmholtz equation) and by experiments. It is found that the resonances and longitudinal mode shapes from our analytical combustor models are reasonably close to numerical ones. To address CI in single-nozzle gas turbine combustors, a closed-loop system is proposed by combining the thermos-acoustic model and flame dynamical model. With closed-loop model, we investigated the impact of mean flow on self-excited frequency and combustion instability within the combustion system. Closed loop model study reveals that changes in the hydrogen ratio in the fuel can significantly influence flame dynamics, thereby affecting combustion instability. The hydrogen ratio is systematically examined using the analytic combustor model and a popular flame model.
more목차 도움말
Abstract I
List of Tables II
List of figures II
Nomenclature IV
1. Introduction 1
1.1 Gas turbines 1
1.1.1 Single nozzle gas turbine combustor 2
1.1.2 GT24 gas turbine combustor 4
1.2 Research background 7
1.3 Combustion Instability 7
1.4 Prediction techniques 10
1.5 Recent Developments 14
1.6 Purpose of study 15
2. Analytical model 17
2.1 Closed loop analysis 17
2.2 Acoustic models 18
2.2.1 Longitudinal acoustic model 18
2.2.2 Annular acoustic model 23
2.3 Flame dynamical model 26
3. Analysis conditions 28
3.1 KIMM Model Operating conditions 28
3.2 GT24 Model Operating conditions 29
4. Results 30
4.1 KIMM Model 30
4.1.1 Flame image analysis to derive time delay values 30
4.1.2 Longitudinal acoustic model verification 32
4.1.3 Influence of mean flow on instability characteristics 34
4.1.4 Parameter study on combustion instability 39
4.2 GT24 Model 43
4.2.1 Results comparison between GT24 EV model and Simplified GT24 EV model 43
4.2.2 Annular acoustic model results 50
4.2.3 Effect of mean flow 51
5. Conclusions 55
References 56
