High-Speed Spray-to-Spray Collision Study on Two-Hole Impinging Jet Nozzles 2015-01-0948

High-speed spray-to-spray liquid impingement could be an effective phenomenon for the spray propagation and droplet vaporization. To achieve higher vaporization efficiency, impingement from two-hole nozzles is analyzed in this paper. This paper focuses on investigating vaporization mechanism as a function of the impingement location and the collision breakup process provided by two-hole impinging jet nozzles. CFD (Computational Fluid Dynamics) is adopted to do simulation. Lagrangian model is used to predict jet-to-jet impingement and droplet breakup conditions while KH-RT breakup and O'Rourke collision models are implemented for the simulation. The paper includes three parts: First, a single spray injected into an initially quiescent constant volume chamber using the Lagrangian approach is simulated to identify the breakup region, which will be considered as a reference to study two-hole impinging jet nozzles. Lagrangian simulation results would be validated via experimental results. Second, collision mechanism is analyzed to obtain probability distribution of collision efficiency and study the jet-to-jet impingement. Finally, the paper examines the collision phenomenon under engine-like conditions, to examine impingement at pre (case 1), exact (case 2), or post (case 3) breakup point. Conclusions from the present study are that case 1 is superior to the other two cases and that Sauter Mean Diameter (SMD) for case 1 has lowest values, resulting in faster vaporization of the small droplets. Additionally, a liquid volume fraction for case 1 is less distributed, thus, meaning that the distribution of vapor phase is greater for case 1 than the other cases.