Novel correlations for the liquid holdup in a gas-liquid slug flow

This paper introduces novel equations for calculating the slug unit liquid holdup (average liquid holdup) and the slug liquid holdup (slug holdup) in liquid-gas slug flow. The equations were tested across various pipe diameters, incline angles, fluid viscosities and densities, system pressures, and liquid and gas flow rates. The correlation utilizes two dimensionless numbers and displays a self-similar nonlinear symmetrical sigmoidal trend. The two parameters used are the ratio of the no-slip liquid holdup to the in-situ liquid holdup and the ratio of liquid superficial velocity to gas superficial velocity. When the superficial velocities ratio is high, all data converge to a single value of approximatly1 for the no-slip to in-situ liquid holdup ratio. The present unified correlations are simple to implement in any slug flow model. It employs defined parameters, and it has already been tested for varying pipe diameters, inclinations, and fluid viscosities that range from water to 962 cP. The presented correlations are unified and unique and not found in public literature. The suggested correlations exhibit superior performance compared to existing correlations and models.