Study on dynamic characteristics of droplet impact on wet wall 2020-01-1429
To better understand the spray impingement on oil substrate and the interaction of the two in a gasoline direct injection engine.It's important to understand the behavior of single droplet impinge on the oil film and composition of the coronal formed by fuel and oil.In this paper, laser induced fluorescence method was used to observe the phenomenon of ethanol droplets impinging on the liquid film of glycerol aqueous solution. The We number of incident droplets, the dynamic viscosity of the liquid film and the dimensionless liquid film thickness were studied. The relationship of fluorescence intensity and coronal composition and the formation mechanisms of coronal and splash were built. Tests have shown that We number have a major promoting effect on crown splash. High liquid film dynamic viscosity and dimensionless liquid film thickness have an inhibitory effect on coronal formation and splash. Under the condition that the We number of incident droplets is equal, the composition of the liquid film in the crown decreases as the dynamic viscosity of the liquid film increases. The proportion of the liquid film in the crown increases as the thickness of the dimensionless liquid film increases . As the We number of droplets increases, the composition of the liquid film in the crown increases.The coronal is developed by the jet, the splash formed when the jet strength overcomes the tension at the top of the crown.