Strojarstvo, vol.52, no.5, pp.543-548, 2010 (SCI-Expanded)
Bubble columns are gas-liquid contactors often used in industry. Although they are used primarily for mass transfer purpose, since gas and liquid phases are fed to the column at different temperatures, direct contact heat transfer becomes important as well. This research is about the heat transfer characteristics of bubble columns. Experiments were carried out using a plexiglass column with dimensions 160x160x1180 mm. Water was first put into the column to the height of 1 m and heated to the desired temperature, and then experiments were performed by introducing ambient air to the column and recording the variation in temperature of water and inlet and outlet air temperatures and humidities. Models developed for the convective heat transfer from the liquid interface to the gas in the bubble were used together with the experimental data to determine the heat and mass transfer coefficients. The volumetric heat transfer coefficient (hGa) was found to vary over the range 0,3-16 kW/(m3·K) with gas flow rate and the volumetric mass transfer coefficient (kGa) in the range 0,35-7,49 kmol/m 3·s·atm.