An Experimental Investigation Of Fuel Spray Vapor Phase Characterization


An experimental study of an infrared laser extinction technique for measuring fuel vapor flux in evaporating liquid fuel sprays was conducted. The infrared laser extinction technique consists of two separate measurements: a visible angular scattering measurement and an infrared line-of-sight extinction measurement. Using this technique, vapor flux along with other spray parameters such as mean drop size and size distribution were measured for a pressure atomized, isooctane fuel spray. Line-of-sight infrared extinction measurements were deconvoluted to obtain radial variations of vapor concentration. Peak vapor concentrations were measured at the spray center due to entrainment effects. Based on the radial mass fraction and measured gas phase velocity profiles, the fuel vapor mass flux was calculated; most of the vapor flux was contained in the centcr of the spray at all axial locations. The fuel vapor mass flux was integrated over the spray area at each axial location to obtain fuel vapor mass flow rates. A detailed error analysis was performed to determine the error sensitivities of the vapor concentration to the measured parameters. The vapor concentration was relatively insensitive to the measured drop size distribution since the vapor absorption was the most dominant mode of extinction. The vapor concentration was most sensitive to the measurement of the infrared extinction ratio. An upper limit for the overall error in the vapor concentration measurement was estimated at 15% over the spray radius.


Mechanical and Aerospace Engineering

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Article - Conference proceedings

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Publication Date

01 Jan 1990