Department of Mechanical Engineering, IIT Madras
School of Civil and Mechanical Engineering, Curtin University, Perth-6845, Australia
Heat Transfer and Thermal Power Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
Many industrial processes such as spray cooling for electronic systems, desalination and refrigeration, and metal quenching involve the phenomenon of droplet impact over hot surfaces. In order to understand these cooling mechanisms, the basic knowledge of droplet interaction such as single droplet, multiple droplet interference over a heated surface is needed. In the present work, a train of two water droplets are impacted over a heated thin Inconel surface maintained at a constant temperature. The hydrodynamics is captured by high speed camera whereas the heat transfer characteristics are filmed using infrared thermography. The impact Weber number, surface temperature and droplet flow rate are chosen as the parameters. The outcomes of the process are measured during the initial single droplet and drop-on-drop impact scenarios and presented in terms of non-dimensional parameters such as spread factor and input heat transfer. The spread and temperature response is recorded for the two droplets impinging the surface separately at two different Weber number values, maintaining three surface temperature conditions. Three droplet flow rates are used at the given surface temperature and impact conditions. The concerning outcomes are calculated via image post-processing techniques and further analysis is carried out. The surface heat transfer effects due to interaction of each droplet is analysed and compared for the single and drop-on-drop configurations.