Model of gas-liquid two-phase flow

Two phases Pressure drops in a pipeline can be calculated by using Bernoulli's equation. According to Bernouilli the pressure drop in an adiabatic pipeline is the result of three independent factors (frictional pressure gradient, momentum pressure gradient and gravitational pressure gradient). After integration the equation of Bernoulli is given by:


Two phase flow calculations can be done in two fundamental ways. Either by assuming an imaginary homogeneous mixture, in which the properties of the liquid and the vapor phase are combined to form mixture properties, or by asuming an heterogeneous mixture with a liquid and a vapor phase which may have different velocities.

The Fortran and spreadsheet programs written during the training period support one homogeneous model (the Dukler model) and two heterogeneous models (the Lockhart-Martinelli and a confidential model). The programs have four main calculation options:

Conclusively, the programs have turned into powerful and reliable tools for two phase gas-liquid flow calculations. The Fortran version is especially useful when calculating the pressure drop over a complex pipeline, including bends, valves or variable diameters. The spreadsheet version is especially useful for quick estimates of pressure drops along a simple pipeline.