Visualization of Effects of Ultrasound on Liquid Droplet Solidification and Frost Formation on Cold Flat Surface

摘要

An experimental study was conducted to investigate the effect of ultrasonic vibrations on frost release from a cold flat surface in atmospheric air flow. A microscopic visualization on the liquid droplet solidification and frost formation process withwithout the effect of 20 kHz ultrasound was made. A water droplet solidification and the frost crystal growth on the solidified water droplet surface were comparatively observed and the frost thickness variation were comparatively analyzed. It was found that almost no different can be seen between the water droplet with effect of ultrasound and that without effect of ultrasound on the droplet solidification onset time. However, almost no growth of the frost crystal can be observed on the solidified water droplet surface after the droplet solidification with effect of ultrasound. In addition, very small growth of the frost layer can be seen with the effect of ultrasound. The experimental results showed that the frost formation process on the cold flat surface can be significantly restrained due to the effect of ultrasound.