Heat transfer analysis of waxy crude oil under a new wide phase change partition model

The waxy crude oil is cooled and the waxy crystals form a grid structure after the shutdown, which leads to a very complicated heat transfer process. The degree of temperature drop of crude oil after shutdown directly determines the formulation of restart plan. How to accurately describe the phase transition heat transfer process of waxy crude oil based on the phase change of wax crystals is a hot issue in the field of crude oil storage and transportation. In this paper, the wax evolution process of crude oil was described, and a new wide phase transition partition model was proposed, with the governing equations being given for each sub-region. In the fuzzy zone of porous media, the Brinkmann-Forchheimer-Darcy seepage model was adopted. The iterative method was used to solve the discrete equations, and the solver adopted strong implicit method. The model and its solution method were verified by experiment. The breaking point was the index to judge the transition of crude oil from liquid phase to porous medium, and different breaking points of different kinds of crude oil correspond to different temperature ranges of porous media, so the influence of different breaking point temperature on heat transfer process was developed. Then, based on the model, the phase change heat transfer process was analyzed by using the change trajectory of the highest temperature point, and the transformation and influence of natural convection heat transfer process were discussed emphatically.