Optical diagnostics in high-speed fuel spray; methodology and analysis

This paper presents a digital imaging and optical characterization system in a high-speed spray jet. Different fuel injection arrangements have been evaluated as part of fuel delivery system prior to application in a rotary “Wankel” engine; the objective being to improve combustion efficiency and engine performance. High-power lasers, high-resolution CCD cameras, and microscopes are employed to perform the experimental work. Image processing is applied to extract both macroscopic and microscopic attributes including spray pattern, spray-cone angle, spray tip penetration and velocity, particle size distribution, and particle velocity. Spray development process during the injection period is reviewed. The effects of changing in fuel-pressure, injector frequency and nozzle size are discussed as well.