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 hig h gas superficial velocities - 0.22 to 2.7 m/s - and at liquid (water) supe rficial velocities of 0 to 0.47 m/s, by means of a differential pressure tr ansducer. The equation of Hills (1976) based on the slip velocity gives goo d predictions of the gas holdup for 0.1 less than or equal to epsilon (g) l ess than or equal to 0.4. However, the holdups predicted by this approach a re considerably higher than the experimental values at gas velocities high enough that epsilon (g) > 0.4. Other equations from the literature are also shown to be inadequate. The new data and earlier data at high gas velociti es are therefore correlated with a new dimensional equation for U-l less th an or equal to 0.23 m/s.