Book Description

Abstract : The fuel spray wall interaction phenomenon plays an essential role in determining the emissions and performance of an internal combustion engine. The investigation of single droplet wall interaction is crucial to understanding of a spray wall impingement process. This report is a compilation of the experimental work done to understand the droplet impingement characteristics, through optical diagnostics and temperature measurement. Different fuels and different surface under ambient and elevated temperature conditions are used for these tests, with two objectives: Development of a common depositionsplashing criteria; and Understanding droplet post impingement dynamics variation with factors like: Weber number (ratio of inertia and surface tension forces), and with temperature. The droplet post impinging characteristics include spread factor, height ratio, contact line velocity and dynamic contact angle. The effect of Weber no on droplet impingement characteristics is investigated using water and diesel. The effect of temperature is divided into two subsections: Isothermal (cold wall-cold droplet and hot wall-hot droplet) and non-isothermal conditions (hot wall-cold droplet and hot droplet and cold wall), to understand the influence of both variation in thermophysical properties and heat transfer between droplet and surface. Using the experimental results, a comprehensive review of splashing criteria is done, along with a proposed new correlation for same and concept of splashing probability is introduced. The observation presented for variation in post-impingement characteristics with the mentioned factors are useful for future development of numerical codes.