Gas holdup for high gas velocities in a gas-liquid cocurrent upward-flow system

Gas holdup has been measured in an 83-mm diameter, 2.2-m high column at high gas superficial velocities - 0.22 to 2.7 m/s - and at liquid (water) superficial velocities of 0 to 0.47 m/s, by means of a differential pressure transducer. The equation of Hills (1976) based on the slip velocity gives good predictions of the gas holdup for 0.1 ≤ ε_g ≤ 0.4. However, the holdups predicted by this approach are considerably higher than the experimental values at gas velocities high enough that ε_g > 0.4. Other equations from the literature are also shown to be inadequate. The new data and earlier data at high gas velocities are therefore correlated with a new dimensional equation for U₁ ≤ 0.23 m/s.