Detailed numerical simulations of unequal sized off-centre binary droplet collisions. (July 2020)

• Record Type: Journal Article
• Authors: Chowdhary, Sarwasva; Reddy, S. Rajesh; Banerjee, R.
• Is Part Of: International journal of multiphase flow. Volume 128(2020)
• Publication Date: 2020-07
• Subjects: Droplet collision -- Impact parameter -- Droplet size ratio -- Volume of fluid model; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2020.103267
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: High fidelity numerical simulations of binary droplet collisions are performed. The geometrical characteristics of ligament structures are presented both qualitatively and quantitatively. Effect of cavity formation in the liquid bridge (connecting the end droplets) on the ligament characteristics is studied. The drainage of mass from smaller droplet to larger droplet is more significant for lower diameter ratio collisions. Abstract: A numerical investigation of the binary collision of two off-center unequal sized liquid droplets in the gaseous environment has been performed. The complete process of collision of droplets is dynamically simulated by solving the incompressible Navier–Stokes equations. Simulations are performed using three-dimensional, multiphase finite volume based solver in OpenFOAM platform. The gas-liquid interface is captured by using the volume of fluid (VOF) method. The solver is appropriately validated and is applied to study the effect of the droplet diameter ratio and the impact parameter on the droplet collision characteristics. The numerical study is done by fixing a moderately high Weber number and Reynolds number for unequal sized droplet collision, where stretching separation is expected as a collision outcome for equal sized droplets. The geometrical characteristics of ligament structures are presented both qualitatively and quantitatively. The satellite droplet formation is also well captured with the present simulations. Post-collision characteristics from the simulations are compared with an existing collision model. It is believed that the present study serves as a first step towards the development of a more accurate droplet collision models.