Characterization of Biodiesel Sprays

Abstract

Internal combustion engines are widely popular and useful in our life to meet different power requirements. Gaseous and particulate emissions emitted from these engines pose major environmental and health issues. Environment-friendly alternate fuels like biodiesel for diesel engine and alcohols for gasoline engines are gaining popularity steadily in the last decade due to faster depletion of conventional fuels reserves and adaptation of strict emission regulations worldwide. However, it is significantly important to review the spray characteristics of these alternative fuels because engine performance and emissions are largely dependent on air–fuel mixing process to a great extent. This chapter mainly focuses on different optical techniques used for spray characterisation. There are two types of spray characteristics, which are important in the context of internal combustion engines, namely macroscopic spray characteristics and microscopic spray characteristics. Macroscopic spray characteristics such as spray tip penetration and spray cone angle are generally characterised by Mie scattering, shadowgraphy and schlieren techniques, by using high-speed CCD camera. Microscopic characteristics such as spray droplet size distribution and droplet velocity distributions are generally measured using phase Doppler interferometry (PDI) technique.