MASS-TRANSFER FROM A DROP .2. THEORETICAL-ANALYSIS OF TEMPERATURE-DEPENDENT MASS FLUX CORRELATION

A new expression of the droplet Sherwood number (Sh) is presented base d on the theoretical treatment of the temperature dependent gaseous di ffusion coefficient. The experimentally specified parameters were corr elated by means of recent data on water droplets evaporating in the fl ow field. The mass flux correlation is given as a function of the Reyn olds (Re) and Schmidt (Sc) numbers, and it turned out to be Sh = (2.00 9 + 0.514Re1/2 Sc1/3). The Sherwood number should be multiplied by a s trictly theoretical correction factor which depends on the droplet and gas temperatures and which is order of 0.9, if the temperature deviat ion is order of 100 K. The introduction of the correction factor seems to remove a discrepancy existing between the earlier theoretical trea tments and experimental data.