Abstract

Spray impingement is a prevalent phenomenon in numerous applications. In turbine combustion chambers and internal combustion engines, spray impingement is a consequence of fuel injection. The impinging spray can result in secondary spray and/or film formation. Characteristics of spray play a major role in combustion performance, hence the importance of understanding the impingement mechanism in this context. A single droplet impinging on a wall is the key phenomenon underlying the whole spray impingement mechanism. A droplet hitting the wall can bounce, smear, break, splash or any combination of these. The fate of such a droplet is a function of various parameters: initial size and velocity, droplet physical properties such as surface tension and viscosity, and wall surface conditions such as wettability, roughness, and temperature. In this talk, a simple analytical model for an impinging droplet will be presented. The model predicts some of the key features of impingement, such as “crowning” and splashing. The effect of the different physical parameters and wall conditions on these phenomena will be discussed.