Planar Laser Rayleigh Scattering for Analyzing Diesel Spray Characteristics

Abstract

The developing and mixing characteristics of a diesel spray were investigated, and under circumstances of changing fuel injection and the ambient gas conditions. The mixing measurement in the diesel spray was conducted using planar laser Rayleigh scattering. Experiments were conducted in an optically accessible, constant-volume combustion chamber. The chamber could simulate the ambient conditions of a typical diesel engine. In this study n-heptane was injected into the chamber and the scattered light from the spray was detected by an ICCD camera. A 532 nm Nd: YAG laser was used as a light source. The experimental results show that an injection pressure has a great effect on fuel vaporizing and in the mixing. Also, an increase in the injection pressure could promote a much leaner fuellambient gas mix. The results showed that an ambient temperature and density do have a great effect on the vaporization of fuel droplets and a development of liquid length in the diesel spray.