선박엔진의 분사조건 변화가 연소 특성에 미치는 수치적 연구

다국어 초록 (Multilingual Abstract)

Ships are a key mode of transportation, carrying approximately 75% of global freight volume, and emit various air pollutants such as carbon dioxide (CO₂), nitrogen oxides (NOx), sulfur oxides (SOx), carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM). These emissions contribute significantly to global warming and air quality deterioration. In response, the International Maritime Organization (IMO) has been progressively strengthening regulations on ship emissions in line with the Paris Climate Agreement and the IPCC target of limiting the global average temperature increase to 1.5 °C. In particular, a long-term target has been established to reduce greenhouse gas emissions from the shipping sector by at least 50% by 2050 compared to 2008 levels, necessitating comprehensive technological responses across the maritime industry. Currently, energy efficiency improvement technologies and alternative fuels are considered major mitigation measures in the shipping sector. However, the application of such technologies to in-service vessels remains limited, and conventional marine diesel engines operating on heavy fuel oil (HFO) are expected to remain dominant in the marine fuel market for the foreseeable future. Given this reality, continuous research focusing on combustion performance improvement and emission reduction for existing marine engines is essential, in addition to studies centered on newbuild vessels and alternative fuels. The combustion characteristics of diesel engines are strongly governed by in-cylinder fuel injection behavior. Fuel injection pressure, injection timing, and injection angle are key parameters that directly affect combustion efficiency and pollutant formation. Variations in injection conditions influence fuel–air mixing, flame propagation, and the formation of localized high-temperature regions, thereby determining nitrogen oxides and particulate matter emission characteristics. Accordingly, this study numerically investigates the effects of fuel injection parameter variations on the combustion and exhaust emission characteristics of a long-stroke marine diesel engine. In this study, a commercial computational fluid dynamics (CFD) code was employed to quantitatively evaluate spray development, fuel distribution, flame temperature, OH radical distribution, and the formation characteristics of CO and NO. By comparatively analyzing combustion behavior under different injection pressures, injection timings, and injection angles, the effects of individual injection parameters on combustion efficiency and emission characteristics were systematically identified. The results demonstrate that an appropriate combination of injection parameters can improve combustion stability while simultaneously reducing nitrogen oxides emissions, fuel consumption, and incomplete combustion products. The findings of this study provide practical guidelines for optimizing fuel injection parameters applicable to existing HFO-fueled marine diesel engines and offer fundamental technical data to support compliance with increasingly stringent international environmental regulations. Furthermore, this work contributes to the development of strategies for the gradual improvement and efficiency enhancement of existing engine technologies, thereby supporting the long-term sustainability of the maritime industry. Keywords : Long-stroke marine engine, Fuel injection pressure, Fuel injection timing, Injection spray angle, Combustion process

목차 (Table of Contents)

• List of Tables ⅲ
• List of Figures ⅳ
• Abstract ⅶ
• 1. 제 1 장 서 론 1
• 1.1 연구 배경 1
• 2. 제 2 장 선박엔진의 성능개선 연구 5
• 2.1 분사 압력 5
• 2.2 분사 시기 8
• 2.3 분사 각도 14
• 3. 제 3 장 연료분사조건의 선박엔진 성능에 미치는 영향 22
• 3.1 수학적 모델 및 계산 조건· 22
• 3.1.1 계산 코드 검정 22
• 3.1.2 수학적 모델 23
• 3.1.3 계산 조건 및 격자 25
• 3.2 계산 결과 27
• 3.2.1 분사 압력 변화 27
• 3.2.2 분사 시기 변화 41
• 3.2.3 분사 각도 55
• 3.3 고찰 69
• 3.3.1 연료 분사 거동 69
• 3.3.2 화염 전파 거동 72
• 4. 결론 82
• 참고문헌 85
• 국문초록 97