A Lumped Parameter Approach for Determining the Pressure Gradient in Gas-Liquid Annular Flows

This study defines a statistic-derived lumped parameter approach to determine the pressure gradient in two-phase annular flows. The statistical model was defined by coupling: (1) the ordinary least squares method (OLS) to determine the relationship between the variables, (2) the variance inflation factor (VIF) to check for multicollinearity issues, and (3) the least absolute shrinkage and selector operator (LASSO) to select the relevant predictors. Finally, a lumped parameter approach is derived based on the classification and regression tree (CART) approach. The model identifies the liquid and gas Reynolds numbers, the liquid phase properties, the pipe diameter, and the surface tension as significant variables influencing the two-phase pressure gradient.