Secondary atomization of water-in-oil emulsion drops impinging on a heated surface in the film boiling regime

Synergistic Effect of the Fuel Microemulsion Characteristics on Drop Interaction with a Hot Wall

“…The higher the value of T 1 , the longer the dispersed phase droplets get larger by both coalescence and vaporization during drop spreading and heating. In this case, the presence of a larger number of the nucleation sites in the form of a larger number of dispersed phase droplets facilitates finer secondary atomization, similar to the more concentrated emulsions as in ref . The environmental indicator, the hydrocarbon-to-ME relative ratio k rel , also has a direct influence on the quantitative characteristics of secondary atomization.…”

“…It is worth noting that the integral criterion A rel includes relative parameters that largely (some of them directly) define the liquid drop impact on a solid surface, and not just selected fuel characteristics. In particular, the parameter μ rel characterizes the viscosity of the fluid being tested, and the energy of viscous dissipation is one of the main drivers defining the spreading dynamics of a drop of this liquid, along with kinetic and surface energy. ,, For example, studies ,, demonstrate that the decrease of liquid viscosity contributes to the increase in the spreading diameter of a drop. During the intensive vaporization at a film boiling this enables the reduction of the size of the secondary droplets and the increase in their quantity.…”

“…Primarily, this parameter shows that the hydrocarbon component in a microemulsion is partly replaced by another liquid substance, e.g., in our case, by FAME and water. Concerning the addition of water, Piskunov et al 20 revealed that dispersed water-in-emulsion systems contributed to finer atomization of the spreading drop compared with the pure hydrocarbon in the film boiling regime. While Ashikhmin et al 24 experimentally established that the addition of a minimum amount of FAME helps to break a spreading drop into a larger number of smaller fragments.…”

“…The abovementioned point (3) represents a very broad field of research divided into two principal categories: mechanisms and features of the primary atomization of multicomponent fuels and additional enhancement of heat transfer and hydrodynamics during the secondary atomization of heterogeneous liquids . In this work, only one of the manifestations of the secondary droplet breakup is considered, namely, when the primary drops interact with the hot surface simulating the impingement of the fuel drops onto the walls of the combustion chamber. − …”

Interaction of Drops and Sprays with a Heated Wall

“…This is caused by the strong nucleate boiling in this area, leading to a higher heat flux compared to the pure conduction as assumed in Eq. (17). From r ≈ 1.6 mm onward the experimental data shows a decrease of heat flux, since the lamella starts The experimental measured heat flux is in most cases higher then the predicted heat flux by conduction.…”