Two phase flows are important in both normal and microgravity operations. Using our recently proposed dimensionless flow pattern maps for microgravity flows, we develop system specific flow pattern maps which can be used in designing such systems.
In the second part, we compare the characteristics of micro-gravity annular flows with normal gravity downward co-current annular flows. It is found that the proper length scale for normalization in microgravity is the length scale defined using the friction velocities based on the pressure gradients. Using the universal velocity profile, we present a correlation for the mean film thickness h+ and the standard deviation h+rms for microgravity annular flows. A comparison of the interfacial friction factors and wave celerities shows that a higher friction factor and a larger celerity are observed in microgravity flows.