Critical and Subcritical Flow of Multiphase Mixtures Through Chokes

Summary Equations that describe isentropic (adiabatic with no friction loss) flow of multiphase mixtures through chokes can be deduced from the general energy equation. These flow equations are valid for both critical and subcritical flow. Equations, physical property correlations for oil/water/natural gas systems, and a computer method that will handle both flow regimes are described. The procedure will determine whether flow will be in the critical or subcritical regime. The analysis method has been tested by comparing measured and calculated flow rates of 1, 432 sets of literature data comprising both critical and subcritical air/water, air/kerosene, natural gas, natural gas/oil, natural gas/water, and water flows. An average discharge coefficient of 0.826 gave a negligible average error with a 15.4% standard deviation.