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

Colorado School Of Mines, Golden CO

Investigators

Abstract

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.