A study on the behavior of pressurized gas injected into liquid between parallel disks - front velocity and residual liquid film

The behavior of a bubble of gas suddenly injected from a nozzle into a liquid between horizontal circular disks is studied experimentally and analytically. If the ratio of the distance between the disks to the nozzle diameter is less than 2, the measured front velocity of the interface agrees well with the corresponding value obtained through analysis. If the ratio is greater than 4, the front velocity qualitatively agrees with that of a single-phase radial wall jet of gas, or takes a value determined by the gravity current. At low gas flow rates, the thickness of the gas-filled portion is dependent on liquid properties alone. A thin liquid film remains as a residue on the upper disk after the passage of the interface. At high gas flow rates, the thickness is almost constant. At low gas flow rates, it depends onthe surface tension and the viscosity of the liquid. (orig.)