Abstract: Spherical pipeline’s inner detector can test and locate subtle leakage in a submarine pipeline. In order to establish a more accurate result, the spherical inner detector must go through the submarine pipe’s vertical segment smoothly. Using standard [k-ε] double-equation model and computational fluid dynamics software Fluent, a three-dimensional simulation about the model ball’s flow field is established on the basis of experimental vertical pipe platform. Also, the critical speed when the ball is passing through the vertical segment is calculated. The outcome speed matches well with experimental data, proving the simulation method correct. On the strength of this simulation, the possibility of whether a detector can pass real submarine pipeline or not is predicted, and the influencing factors are analyzed. A conclusion is achieved that the diameter ratio between the ball and the pipe is a significant parameter, which guarantees the spherical inner detector passing the submarine pipe’s vertical segment without barrier under a normal working condition of flow speed [0.8~1.2 m/s], when it is lager than 73 percent.

Key words: vertical pipeline, spherical inner detector, fluid simulation, thrust calculation, passing ability

摘要： 球形内检测器能准确地检测和定位海底管道微小泄漏，为实现其对微小泄漏的检测和定位，必须保证球形内检测器顺利通过海底管道立管段。应用标准[k-ε]双方程模型和流体计算软件Fluent 14.0，对实验平台立管道内模型球周围流场进行三维数值仿真，并计算模型球通过立管段的临界速度。该速度与实验数据很好吻合，验证了仿真方法的正确性。基于此仿真方法，预测球形内检测器在实际海底管道立管段内的通过性并分析其通过性影响因素。得出结论：球管径比（球体直径与管道直径的比值）是一个很重要的参数，球管径比大于等于73%时，球形内检测器在流速为0.8~1.2 m/s的正常工况下能顺利通过海底管道立管段。

关键词: 立管道, 球形内检测器, 流体仿真, 推力计算, 通过性