Abstract
The flame propagation phenomenon of fuel droplet array has been studied for basic research of the spray combustion mechanism. The investigations on fuel droplet-array combustion have been conducted by microgravity experiments for research on essential mechanism of spray combustion. The fine fuel droplets spray during combustion, which partially evaporated prior to flame propagation. It is essential to consider the influence of pre-evaporation of fuel droplets on combustion for better understanding of spray combustion mechanism. In this study, it was performed that measured preevaporating vapor concentrations of the hydrocarbon fuel droplet using infrared absorption method based on the Beer-Lambert law. The Beer-Lambert law relates the absorption of light to the properties of the material through which the light is traveling. It was utilizing that the absorption wavelength due to the stretching vibration of CH bonds in hydrocarbon fuels, such as n-decane were same as He-Ne infrared laser wavelengths (3.39 gm). Infrared absorption measurements were carried out in two stages. (1) Calculation of the extinction coefficient E. It was performed that the measurement of 4 conditions of equivalence ratio could be calculated extinction coefficient 8.7x10-3 (equivalent ratio' ・ mm-1) (2) Measurement of vapor concentration near n-decane droplets. Measurement of the n-decane vapor concentration and thickness were performed in five conditions at 300, 350, 400, 450 and 500 K. It was able to measure the fuel vapor concentration near fuel droplets.
