Dynamic multiphase flow behavior inside a mixed flow Electrical Submersible Pump (ESP) has been studied theoretically for the first time. The main goal is to model two-phase flow behavior in an ESP. A three-dimensional CFD model has been developed to describe the operational envelope of the ESP, namely the onset of surging. The theoretical study includes CFD simulations for the prediction of the flow behavior inside the pump. The CFD modeling depends on two important variables, namely the bubble size and the bubble drag coefficient. The bubble size has been measured and a physically based correlation presented in Barrios (2007) is used. A new correlation for the drag coefficient is used (Barrios 2007) as a function of rotational speed and Reynolds number. Single-phase and two-phase flow CFD simulations were carried out to investigate liquid flow field. Results from the CFD simulations are consistent with the experimental data (Barrios 2007).
