On the measurements of regime transition in high-pressure bubble columns

Two approaches are adopted in this study to identify the flow transition in a bubble column from the homogeneous regime to the heterogeneous regime at pressures up to 15.2 MPa and temperatures up to 78 degrees C. These approa ches, which yield essentially identical results, include those based on the standard deviation of the pressure fluctuation and the drift flux model. T he experimental results obtained indicate that the regime transition veloci ty is delayed when the system pressure and temperature increase. The correl ation proposed for the transition velocity by Wilkinson et al. (1992) predi cts the present results to a reasonable extent, provided that the experimen tally measured values for the physical properties of the fluids are used in the correlation. It is clear, however, that an improved correlation or mod el is needed for a quantitative account of the transition velocity for high -pressure bubble column systems with different gas distributing capability.