The influence of liquid pool temperature on the critical impact Weber number for surface bubble formation

A series of experiments were conducted concerning the influence of liquid pool temperature on the formation of surface bubble. Single water droplet impacted on an ethanol pool 56 mm in depth, and the droplet diameter is about 2 mm. The impaction processes were recorded using a high-speed photography camera with 2000 fps. All the experiments were performed at 20 °C and the ethanol pool was heated by a hot plate. The result reveals that the critical Weber number for forming surface bubble is affected by the pool temperature, decreasing with the increase of impacted liquid temperature.