Heat transfer together with phase change in pipelines frequently occurs in petroleum and chemical industries. Numerical methods have been extensively used in modeling two-phase flow and become more complicated when the phase change process is involved. One-dimensional two-fluid models are unreliable for modeling phase behavior because they do only yield uniform velocity/temperature distributions. Thus, mathematical models based on bipolar coordinate systems have been developed, where nonisothermal flows and heat/mass transfer have been implemented to predict the varying vapor-liquid interface and component mass fraction. The PR equation is chosen for phase equilibrium calculation and the P-T flash is used to evaluate the physical properties, gasification rate, and enthalpy departure. The liquid holdup, velocity/temperature profile, and phase fraction could be predicted along the pipeline, which are important for transportation optimization and flow assurance. The numerical predictions fit well with available experimental and simulated data and could present more detailed and accurate results.