Time-Resolved Liquid and Vapor Phase Distribution Measurement in Diesel Sprays Using a Light Absorption Scattering Technique

The laser absorption scattering (LAS) technique [Suzuki, et al., 1993, SAE Technical Paper, 930863] is a line-of-sight extinction technique that has several advantages such as high signal-to-noise ratio, low ambient temperature dependence and no fluorescence quenching. However, the LAS technique has been limited to single-shot measurements, which means only one spray image could be captured in one injection event. In order to record the whole vapor phase distribution development in one injection event, a new approach was developed using high-speed video cameras, and n-dodecane with 2% and 10% 1-methylnaphthalene was used as model fuels. Spray imaging was carried out in a spray chamber with temperature varied in the range 423 – 653 K, the ambient pressure was kept constant at 58 bar, and a fuel injection pressure of 800 –1200 bars was applied. It was shown that using UV light and visible light, the detailed liquid and vapor phase distribution development was captured clearly for both 2% 1-MN and 10% 1-MN fuel. Extinction tends to be saturated in UV images with 10% 1-MN fuel at various ambient temperatures. However, with 2% 1-MN fuel, there is no saturation at the applied conditions