Consider two phase gas/liquid flow in a vertical column of cross sectional area 100 cm2. The rise of the bubbles relative to a stagnant liquid above is 25 cm/s. The regime is thought to be that of bubble flow. If the upward gas and liquid volumetric flow rates are QG = 250 cm3/s and QL — 0 , respectively. What is the void fraction (a) , and is this likely to correspond to bubble flow? If the liquid is water, the gas density is negligible, and the height of the two phases is 100 cm, what is the pressure drop in Pa across the column? If the gas is turned off, to what height does the liquid settle? The void fraction is given by: