基于容弹系统的低速船机喷雾及燃烧数值模拟研究

发布时间：2023-05-30 20:21

　　大型低速二冲程柴油发动机具有较高的热效率,动力性和耐久性等优点。由于其高效率和高可靠性,大型二冲程船用柴油机成为货船的主要动力。在不降低热效率的情况下降低发动机排放是一项具有挑战性的任务。实际上,燃烧效率和排放物形成都强烈依赖于燃烧特性,而燃烧主要决定于混合气的形成,例如液滴的分解、蒸发和与空气混合。同时,缸内流动的影响在上述过程中起着重要作用。由于经济性的原因,现在都用重质燃油(HFO)作为船舶的燃料,这些燃料含有大量轻质燃料精炼后的残留物,如硫和金属。这种燃料粘稠度高,需要在发动机使用之前加热。随着人们环保意识的增强,为了限制和控制船舶有害物质的排放。1997年9月27日,国际海事组织(IMO)与国际防止船舶污染公约(MARPOL)(73/78)签订了MARPOL公约,其中船用柴油机排放的NOx排放限值在附录VI中明确规定,并于2005年5月19日对所有已签署协议的船舶生效。船舶污染的国际公约(MARPOL 73/78)的附件六是使船舶空气污染物合法化的主要国际公约,为降低海洋船舶排放氮氧化物提出了渐进的要求。NOx排放控制分为三个阶段,第一阶段氮氧化物排放限制适用于2000年1月...

【文章页数】：70 页

【学位级别】：硕士

【文章目录】：
摘要
ABSTRACT
Chapter 1. Introduction
    1.1 Historical development and current trend of marine low-speed diesel engine
    1.2 Introduction to marine engine
        1.2.1 High speed marine diesel engine
        1.2.2 Medium speed marine diesel engine
        1.2.3 Low speed marine diesel engine
    1.3 Current research status of NOx emission reduction technology for marinelow speed diesel engine
        1.3.1 Gas fuel or dual fuel
        1.3.2 Optimize the fuel injection timing
        1.3.3 Exhaust gas recirculation
        1.3.4 Turbocharged
        1.3.5 Miller cycle
        1.3.6 Humidification technology
        1.3.7 Selective Catalytic Reduction
    1.4 Injection Process
        1.4.1 Direct Injection Diesel Engine
        1.4.2 Jerk Injection
        1.4.3 Common Rail Injection
        1.4.4 Timed Injection
    1.5 Combustion Process
        1.5.1 HCCI
        1.5.2 PCCI
        1.5.3 RCCI
    1.6 Summery
Chapter 2. Numerical Models
    2.1 Basic Control Equations
        2.1.1 Gas phase control equation
        2.1.2 Liquid Phase Control Equation
    2.2 Turbulence Model
    2.3 Spray Model
        2.3.1 Droplet Breakup Model
        2.3.2 Other Spray Models
    2.4 Combustion model
        2.4.1 The Shell Model
        2.4.2 Characteristic Time Scale Combustion (CTC) Model
    2.5 Emission model
        2.5.1 Soot model
        2.5.2 NOX Model
    2.6 Summary of this chapter
Chapter 3. Study of Spray Characteristic in Constant Volume CombustionChamber
    3.1 Calculation Conditions
    3.2 Verification of spray model
    3.3 Influence of Ambient Pressure
    3.4 Influence of swirl
    3.5 Influence of nozzle diameter
    3.6 Influence of injection pressure
    3.7 Influence of ambient temperature
    3.8 Influence of Injector Holes Position Variation
    3.9 Influence of Swirl
    3.10 Summary of this chapter
Chapter 4. Study on Heavy Oil Combustion and Emission in CVCC
    4.1 Calculation Conditions
    4.2 Effect of Oxygen Concentration on Combustion and Emissions
    4.3 Summary of this chapter
Chapter 5. Conclusion
References
Acknowledgement



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