Numerical study and sensitivity analysis of two-phase oil-water flow and heat transfer in different flowline orientations using OpenFOAM

Evaluating the oil-water temperatures in flowlines is demanding mostly in deep offshore applications where flow assurance issues and dramatic heat transfer are anticipated to occur. Consequently, a 3-D mathematical model of oil-water Newtonian flow under non-isothermal conditions is established to investigate the mechanisms of the two-phase oil-water transportation and heat transfer in horizontal and inclined flowlines. In this study, a non-isothermal two-phase flow model is first modified and then implemented in the InterFoam solver by introducing the energy equation using OpenFOAM® code. The Low Reynolds Number (LRN) k-ε turbulence model is employed to resolve the turbulence phenomena within the oil and water mixtures. The flow patterns, local heat transfer coefficients (HTC), and relative errors for two-phase oil-water flow at different flowline orientations (0o, +4o, +7o) are compared with the experimental literature results. The model was also employed to ascertain the effect of input water cuts and flowline inclinations on the flow regimes, and the results were validated in literature with a high accuracy level. Global sensitivity analysis is then conducted to determine the effect of the different parameters on the output temperature and pressure of the produced two-phase hydrocarbon systems. Subsequently, HTC and flow patterns for oil-water flows at different inclinations of −10o, -4o, and +10o can be predicted by the model. The velocity distribution, liquid holdup, pressure gradient, and temperature variation at the flowline cross-sections are simulated and analyzed extensively