在天然气管道输送系统中，串联弯管由于其特殊结构以及天然气出砂特性，管道弯管处特别容易受到冲蚀的影响。串联弯管的冲蚀行为受到多个因素的影响，其中两弯头的连接管长度是不可忽视的变量。为此采用计算流体动力学（computational fluid dynamics, CFD）-离散相模型（discrete phase model, DPM）数值模拟方法，对含砂天然气在不同间距下串联弯管冲蚀行为进行研究。结果表明：当两个弯管串联安装时，下游弯管的腐蚀形貌和速率受两个弯管之间距离的影响较大。随着串联弯管中间段长度的增加，上游弯管的腐蚀形貌均呈V字形，但下游弯管的腐蚀形貌则由三角形逐渐变化为V字形。此外，因重力对砂粒运移轨迹产生的影响，下游弯管冲蚀磨损最严重区域相较于上游弯管要靠后5° ~ 8°。通过对下游弯管多角度切面流场进行分析，气流经过中间段后在下游弯管处产生了较复杂的二次流，因此下游弯管的最大冲蚀速率随着串联弯管中间段长度的增加，呈现出先减小后增大的变化规律。研究成果可为优化双弯管系统的工程设计和冲蚀防控提供一定的理论指导和依据。

In the natural gas pipeline transportation system, the series elbows is particularly susceptible to erosion due to its special structure and the sand-producing characteristics of natural gas. The erosion behavior of the series elbows is affected by multiple factors, among which the length of the connecting pipe between the two elbows is a variable that cannot be ignored. For this reason, the computational fluid dynamics(CFD)-discrete phase model(DPM) numerical simulation method was used to study the erosion behavior of the series elbows at different spacings of sand-containing natural gas. The results show that when two elbows are installed in series, the corrosion morphology and rate of the second elbow are greatly affected by the distance between the two elbows. With the increase of the length of the middle section of the series elbow, the corrosion morphology of the first elbow is V-shaped, but the corrosion morphology of the second elbow gradually changes from a triangle to a V-shape. In addition, due to the influence of gravity on the migration trajectory of sand particles, the area with the most serious erosion and wear of the second elbow is 5° to 8° behind the upstream elbow. By analyzing the multi-angle section flow field of the second elbow, it is found that the airflow generates a more complex secondary flow at the second elbow after passing through the middle section. Therefore, the maximum erosion rate of the second elbow decreases first and then increases with the increase of the length of the middle section of the series elbows. The research results can provide certain theoretical guidance and basis for optimizing the engineering design and erosion prevention of the double elbow system.