Analysis Of Heat Transfer Performance Of Deep-Water Phase Change Material Sandwich Pipes

In recent years,the exploitation of oil and gas has gradually entered the deep sea.Under the low-temperature and high-pressure deep sea environment,the reduction of the oil temperature in the oil and gas pipeline can easily lead to the formation of wax crystals and hydrates,causing blockage of pipelines.Therefore,the flow guarantee is the important prerequisite of the deep-sea oil and gas pipeline's operation.The traditional way of pipe insulation is mainly electric heating and thermal fluid heating.In recent years,thermal insulation materials have been widely used in architecture and other areas because of their good heat storage and release characteristics.Drawing on this idea,phase change materials are used in subsea pipelines.In this paper,the phase change material sandwiched pipe is taken as the research object,the heat transfer characteristics of the deep-water phase change material sandwich pipe are studied through the combination of theoretical analysis and numerical simulation.The main contents include: Firstly,through the establishment of two-dimensional and three-dimensional pipe models,analyzed the temperature distribution along the pipeline and the radial temperature distribution of the pipeline under steady oil flow conditions.Secondly,by using transient heat transfer,the effects of phase change material parameters,the proportion of phase change material in the insulation layer,and the difference in the ratio of phase change materials in the insulation layer on the insulation performance are analyzed to obtain the best results.Insulation material and optimal insulation layer layout;finally,the thermal storage and the phase change conditions of the phase-change material sandwich pipe is studied under the re-starting condition.The results show that the effective holding time of the phase change material insulation layer is close to 1.4 times that the non-phase change material insulation layer,and the melting point size has little effect on the insulation material.The closer the phase change material is to the inner tube,the better the insulation effect.This study provide guidance for the design and utilization of phase change material sandwich pipe.