Abstract: In the gas pipeline, the gas⁃solid two⁃phase flow causes erosion and wear on the inner wall of the pipeline, and the erosion wear in the tapered tube is particularly serious. Using the knowledge of computational fluid dynamics, the model was established by CFD simulation software, the fluid⁃solid two⁃way coupling equation was used, and standard k⁃ε model and discrete⁃phase model (DPM) were used for analysis. Investigating the influence of inlet flow velocity, solid particle size and particle mass flow rate on the wear and tear of reducing pipe, and predicting the location of the tapered tube where erosion wear is likely to occur and the optimum flow rate of natural gas. The results show that the inlet flow rate increased from 5 m/s to 25 m/s, the maximum erosion rate of the tapered tube increased first, then decreased and then increased. When the inlet flow rate is 15 m/s, the erosion rate reached the minimum, which is 1.76×10-6 kg/（m2•s）. The particle size increases from 0.5 mm to 4.5 mm, and the maximum erosion rate increases from 4.23×10-6 kg/（m2•s）to 7.56×10-6 kg/（m2•s）, and then gradually decreases to 2.68×10-6 kg/（m2•s）. The particle mass flow rate increases from 0.1 kg/s to 0.6 kg/s, when the inlet flow rate is 15 m/s, the maximum erosion rate increases from 1.76×10-6 kg/（m2•s） to 1.00×10-5 kg/（m2•s）. The erosion wear area is mainly located on the lower wall surface of the tapered tube throat, the lower wall of the tapered tube segment from the 2D region of the throat and the upper wall of the tapered tube segment outside the 2D region, and the erosion wear area of the upper wall surface is approximated by "U" type symmetrical distribution. During gas transfer, the optimum inlet flow rate of gas through the reducing pipeline should be 15 m/s. In order to prevent erosion and wear, it should also be noted that the particle size should not be too small, and the mass flow rate should be controlled within a reasonable range.

Key words: Particle attribute, Gas transmission pipeline, Gas?solid two?phase flow, Reducing pipe, Erosion wear, Simulation prediction

摘要： 在输气管道中，气固两相流对管道内壁造成冲蚀磨损，渐缩管中冲蚀磨损情况尤为严重。利用计算流体动力学相关知识，通过CFD仿真软件建立模型，运用流固双向耦合方程，采用标准k⁃ε模型和DPM模型进行分析。探究入口流速、固体颗粒粒径以及颗粒质量流率对渐缩管冲蚀磨损现象的影响，预测渐缩管中易发生冲蚀磨损的位置以及天然气的最佳流速。结果表明，当入口流速从5 m/s增大到25 m/s时，渐缩管最大冲蚀速率先增加后减小再增加；当入口流速为15 m/s时，冲蚀速率降至最小，为1.76×10－6 kg/（m2•s）；当颗粒粒径从0.5 mm增大到4.5 mm时，最大冲蚀速率先由4.23×10－6 kg/（m2•s）增加至7.56×10－6 kg/（m2•s），而后又逐渐减小至2.68×10－6 kg/（m2•s）；在入口流速为15 m/s的情况下，当颗粒质量流率从0.1 kg/s增大到0.6 kg/s时，最大冲蚀速率从1.76×10－6 kg/（m2•s）增加至1.00×10－5 kg/（m2•s）。渐缩管冲蚀磨损区域主要位于渐缩管喉部下壁面、距离喉部2D区域的收缩管段下壁面及2D区域以外的收缩管段上壁面，并且上壁面冲蚀磨损区域近似呈“U”型对称分布。在输气过程中，气体流经渐缩管的最佳入口流速应为15 m/s。为预防冲蚀磨损，颗粒粒径不宜过小，质量流率需控制在合理范围内。

关键词: 颗粒属性, 　输气管道, 　气固两相流, 　渐缩管, 　冲蚀磨损, 　仿真预测