Effect of pipe diameter on heat transfer characteristics of waxy crude oil pipeline during shutdown

Abstract

Additional specific heat capacity method and momentum source term method are used to establish the mathematical model of the heat transfer process in different diameter waxy crude oil pipeline, and the finite volume method is used to solve the mathematical model. The average temperature of the crude oil in the pipeline with smaller pipe diameter decreases faster. At the initial stage of shutdown, there is a layer of low-temperature crude oil near the pipe wall. The smaller the pipe diameter is, the bigger the thickness of this layer of low-temperature crude oil is. When crude oil is shut down in the pipeline with small diameter, the flow speed of crude oil is limited, and the flow of crude oil is stable and slow. When crude oil is shut down in the pipeline with large diameter, there will be a flow structure of two eddies, the flow speed is relatively large. With the same average temperature of crude oil, the larger the diameter of the pipe, the more difficult it is to form a complete gel structure in the center of the pipeline. Keywords: Waxy crude oil, Pipe diameter, Numerical simulation, Heat transfer characteristics