High-Pressure Combustion of Transient Dense Sprays: An Experimental, Theoretical, and Numerical Investigation of the Relationship between Spray Physics and NOx Emissions

本文研究了作为控制参数的燃油喷射与柴油机排放之间的关系。具体地说，这项研究解决了一氧化氮的形成与高压浓雾燃烧动力学、脉冲喷射和喷雾瞬变之间的关系。实验工具包括定制的柴油发动机模拟器，该模拟器能够在喷射前立即产生与柴油中的条件类似的条件，红外散射测量可以量化燃油液滴尺寸和密集喷雾区域的液体体积分数，线拉曼测量可以量化燃料/空气比和温度。利用傅里叶变换红外光谱对燃烧后气体进行分析，可以测量作为操作参数和所注入燃料的函数的一氧化氮。建模包括微尺度(单液滴)、中尺度(多液滴)和宏观系统。模型用于预测发动机排放随喷射参数变化的趋势。为了使物理系统和数值系统尽可能接近相同，建模和实验工作之间的持续交互是必要的。

This is a study of the relationship between fuel injection as a controlling parameter and emissions from diesel engines. Specifically, the study addresses the relationships between formation of nitric oxide and high-pressure dense-spray combustion dynamics, pulsed injections and spray transients. Experimental tools include a custom-built diesel engine simulator capable of producing conditions similar to those in a diesel immediately prior to injection, infrared scattering measurements to quantify fuel droplet size and liquid volume fraction in the dense-spray region, and line Raman measurements to quantify fuel/air ratio and temperature. Post-combustion gas analysis by Fourier transform infrared spectroscopy allows measurement of nitric oxide as functions of operating parameters and fuel injected. Modeling includes microscale (single droplet), mesoscale (multiple droplet), and macroscale systems. Models are used to predict emission trends in engines as a function of injection parameters. Continuous interaction between the modeling and experimental efforts are necessary to make the physical and numerical systems as nearly identical as possible.