Evaporation rates of drops in forced convection with superposed transverse sound field

Abstract

Evaporation rates for single drops of distilled water suspended in dry air in upwards motion and subject to a horizontal standing wave sound field have been measured from photographic records. The range of drop diameter (0.8–2mm), sound pressure (132–152dB) and frequency (82–734 Hz) yielded parameter ranges of oscillating Reynolds number 16 < Re < 180 and Strouhal number 0.3 < S < 2.8 at convective Reynolds numbers in the range 5 < Re c < 45. Empirical correlations are presented for S < 1 and S > 1, respectively. The data for these cases show the increase in Nusselt number owing to the sound field to be 5–90% and 8–30%, respectively.