| Optical diagnosis has become an important method to study the condition of combustion in the engine cylinders.As one of the most important pyrometry on the basis of heat radiation theory,two-color method can measure the temperature and soot density of spray flame,which is helpful to study the engine combustion and mechanism of pollutant formation,thus to provide necessary information for the design of advanced combustion system for diesel engines.Although two-color method has been used for many years,many factors still deteriorate the accuracy of measurement and not enough researches are conducted to analyze the corresponding errors and uncertainties.In this research,two-color theory and methodology are introduced firstly.Then the errors and uncertainties are analyzed in detail from four parts:theory,calibration procedure,spray flame experiment and data process.Different from traditional set-up of two-color method,high speed RGB video camera was used instead of traditional photodiode and monochrome camera in this project,which is able to detect both the spatially-resolved and temporally-resolved results of temperature and soot density?KL?in the spray flame.By using two independent ones of RGB three channels,two-color setup can be greatly simplified.As one of the new-type combustion technologies for engines,low temperature combustion?LTC?has potential to reduce the particle matter?PM?and nitric oxide?NOX?simultaneously.In this research,temperature and soot density?KL?of spray flame for diesel-butanol blends and neat diesel are studied under different ambient O2 concentrations.The experimental result shows that the flame of diesel-butanol blends has a lower integral level for both flame temperature and soot density than neat diesel flame,achieving the simultaneous reduction of PM and NOX.On the other hand,results show that as the O2 concentration,the flame temperature has a dropping tendency and the soot oxidation rate was reduced. |
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