Suppression of frosting on a metal surface using ultrasonic vibrations

The authors have observed the accumulation of frost on the surface of a rectangular duralumin plate (20 mm/spl times/92.6 mm) flexurally vibrating approximately at 37 kHz in the atmosphere of almost 100% relative humidity at 2 degree in temperature. The plate surface, which got refrigerated at a temperature down to -20 degree with cool carbon-dioxide gas in the experiments, had been ground in advance with abrasive slurry (thick water suspension of carborundum) such that its average surface roughness was maintained at about 100 nm. Experiments were conducted with and without silver-oxide particles spread on the plate surface so as to examine the effect of the ice crystal nuclei. Ultrasonic vibrations with the amplitude of 3.1 microns (rms) are found to have the effect of decreasing the frost accumulation approximately by 60%.