Capsule hydraulic transportation is a kind of low-carbon and environmentally friendly pipeline transportation technique. In this study, the flow velocity characteristics in the pipeline when the capsule is transported in a straight pipe section were simulated by adopting the RNG (Renormalization Group) k–e turbulence model based on Fluent software and experimentally verified. The results showed that the simulated value of flow velocity in the pipeline was basically consistent with the experimental value during transportation of the material by the capsule, and the maximum relative error was no more than 6.7%, proving that it is feasible to use Fluent software to simulate the flow velocity characteristics in the pipeline when the capsule is transported in a straight pipe section. In the process of material transportation, the flow velocity distribution of the cross-section near the upstream and downstream sections of the capsule was basically the same, which increased with the increased length–diameter ratio of the capsule. The axial flow velocity was smaller in the middle of the pipe and larger near the inner wall of the pipe. From the inner wall to the center of the pipe, the radial flow velocity first increased and then decreased. The circumferential flow velocity was distributed in the vicinity of the support body of the capsule. The axial flow velocity of the annular gap section around the capsule first increased and then decreased from the inner wall of the pipe to the outer wall of the capsule. In the process of transporting materials, the influence of the capsule on the flow of its downstream section was greater than that of its upstream section. These results could provide a theoretical basis for optimizing the technical parameters of capsule hydraulic transportation.

中文翻译：

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水平管内胶囊水力输送流速特性数值模拟

胶囊水力输送是一种低碳环保的管道输送技术。本研究采用基于Fluent软件的RNG（Renormalization Group）k-e湍流模型对胶囊在直管段输送时管道内的流速特性进行了模拟，并进行了实验验证。结果表明，管道内流速模拟值与胶囊输送物料过程中的实验值基本一致，最大相对误差不超过6.7%，证明使用Fluent软件是可行的模拟胶囊在直管段运输时管道中的流速特性。在物料运输过程中，胶囊上下游附近截面的流速分布基本一致，随着胶囊长径比的增大而增大。轴向流速在管道中部较小，在管道内壁附近较大。从管内壁到中心，径向流速先增大后减小。圆周流速分布在胶囊的支撑体附近。围绕胶囊的环形间隙部分的轴向流速从管道内壁到胶囊外壁先增大后减小。在输送物料的过程中，胶囊对其下游段流动的影响大于其上游段。