海底双层保温管热膨胀分析

Thermal Expansion of Subsea Pipe-in-Pipe Systems

管道运行期温度高于安装温度，由于管道温差和内压的作用会引起管道的膨胀，而膨胀对立管系统产生影响，因此对管道进行热膨胀分析很有必要。考虑内外管相互作用，从应变的角度出发，求出双层管结构的过渡长度，并分别推导出管道的热膨胀位移以及内外管轴向力的计算公式，编制计算程序，并将计算结果与商用软件计算结果对比。通过算例计算表明，该理论方法计算的结果与商用软件DPIPE计算结果吻合，可以为工程中双层保温管热膨胀分析提供理论依据。

Because of the expansion caused by pipeline temperature difference and internal pressure, there is expansion displacement in pipeline termination, which will affect the total riser system, so thermal expansion analysis is absolutely necessary. Considering the interaction of the inner pipe and the outer pipe, this paper presents a comprehensive mathematical model for the thermal expansion of pipe-in-pipe systems based on the pipe strain to calculate the length of transition and the displacement of the pipe and also the axial force for both inner and outer pipe. A computational example shows that the results by the computational equation agree with the results calculated by business software, so it provides theoretical basis for engineering design in calculating the expansion displacement and axial force of pipe-in-pipe systems.