QUANTIFICATION OF 3D TRANSIENT FUEL FILMS FOR G-DI SPRAYS UNDER ELEVATED AMBIENT CONDITIONS

This paper describes the development of a quantitative Laser Induced Fluorescence (LIF) technique to measure 3Dimensions of transient liquid fuel films formed as a result of spray impingement. It follows work from Alonso et al [1] who proposed using total internal reflection to control the propagation of a laser beam so as to target the excitation of the liquid fuel film only and not the airborne droplets above the film. The LIF technique relies on the principle that upon excitation by laser light the intensity of the fluorescent signal from a tracer is proportional to the film thickness. A Nd:YAG laser was used as the excitation light source (utilising the fourth harmonic at wavelength 266nm) and an intensified CCD camera recorded the results as fluorescent images. A binary mixture of 3-Pentanone in Isooctane was used as a substitute of gasoline due to its similar properties. This paper presents some preliminary experimental results of a transient spray from a gasoline direct injector impinging on to a quartz crown, with observations of the development of the transient fuel film at elevated ambient conditions relevant to G-DI application. Paper ID ILASS08-7-3