Periodic Report Summary 1 - NONSPHERICALDROPLET (Understanding non-spherical droplet vaporisation of single-component hydrocarbon fuels and multi-component biofuel blends)
Understanding of liquid vaporisation has been long considered an important topic in improving multi-phase flow and combustion models and has been studied extensively over the years. Despite that, limited information has become available for the vaporization of non-spherical droplets while use of biofuels and their blends further complicates the process. The importance of atomisation is widely accepted by academic and industrial communities and has been extensively studied experimentally and theoretically for various applications, such as the efficient distribution of agricultural sprays, the formation of raindrops in the atmosphere and the mixing of liquid fuels in combustion systems. To a large extent, the current understanding of the primary and secondary breakup of fuel jets is derived from fundamental experiments conducted on single-component liquid jets and simplified nozzle geometries. Secondary droplet breakup is more commonly studied using realistic injectors and fuels although the high density of the sprays often restricts the measurements to locations that are closer to the cylinder liner than to the nozzle orifice. The spherical droplet approximation is convenient, both in experimental and theoretical studies, but it is overly simplistic for most practical applications since the droplet has a non-spherical shape for the most of its lifetime. Droplet deformation and breakup processes are expected to be affected by the shape, size and orientation of non-spherical droplets relative to the surrounding air motion. Heat transfer and evaporation will be directly affected by the morphology of deformed droplets through a number of processes, including the increased surface area between the liquid and surrounding gas.