Measurement of residence times,and film and drop velocities in two phase annular flow

The development of tracer pulse techniques for measuring mean film and droplet velocities (film and droplet residence times) in vertical two phase annular flow is described. Results of experiments are discussed, and compared to a computer simulation of a tracer pulse in annular flow as described by the interchange model. The experiments show that the mean film velocity can be determined accurately, but not the droplet velocity. The computer simulation supports the experimental results. The effect of interchange is also shown to be sufficiently large in much of the annular flow region to give average film and droplet residence times which are not greatly different.