Deformation of liquid droplets during collisions with hot walls: Experimental and numerical results

Measurements of droplet deformation during wall impingement were performed for ethanol droplets and water droplets with diameters ranging from 100 to 200 mu m. The wall temperature is well above the Leidenfrost temperature of the droplet liquid. With monodisperse droplet streams and a special illumination technique, slow motion images of the phenomena can be obtained. Measurements with high temporal resolution below 1 mu s are possible using a standard video camera. The experimental results are compared with numerical results, which were obtained by solving the three dimensional Navier-Stokes equations for incompressible fluids including surface tension effects. The fluids are treated with the volume-of-fluid method and the free surface is modeled according to the continuum-surface-force model. Numerical and experimental results show good agreement.