Waxy crude oil exhibits complex rheological properties, and the shutdown of pipelines transporting this crude oil will pose a serious threat to the safe operation of pipelines. To accurately depict the temperature drop process of waxy crude oil pipeline during shutdown period, a coupled model including constitutive equation, continuity equation, momentum equation, energy equation and heat conduction equation is established. Moreover, a series of numerical methods from grid generation to equation solving, which are developed by codes in house, are adopted to solve the model. Based on the mathematical model and numerical methods, the shutdown process of a buried waxy crude oil pipeline is numerically simulated, and the characteristics of temperature drop are revealed. The results indicate that the heat transfer in the entire region is dominated by natural convection in the early stages, and the heat transfer mode transitions from Newtonian fluid natural convection to non-Newtonian fluid convection, and then to heat conduction.

numerical simulation, buried pipeline, waxy crude oil, non-Newtonian fluid, temperature drop, natural convection