Finding the Mean Droplet Size

A gas having a density of 13 kg/m and a d5Tiamic viscosity of 0.006 cp flows through a pipe of 30 cm internal diameter at 6.7 m/s. Entrained in this gas is a liquid hydrocarbon having a density of 930 kg/m . A two-phase flow map indicates mist-annular flow. The interfacial tension (or IFT ) = 20 dynes/cm. Compute the Sauter-mean and volume-mean droplet diameters. 

To convert to a consistent set of units, we elect to express the IFT and the gas viscosity in SI units  

Substituting the above two dimensionless ratios, along with the pipe diameter and density values into Eq. 13.4.1, we obtain. 

by weight or by volume, approximately 50% of the droplets flowing in the pipe will be smaller than, and 50% larger than, 1300 /im or 1.3 mm. 

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