基于正交试验的90°弯管冲刷腐蚀数值模拟及实验研究

Numerical Simulation and Experimental Study on Erosioncorrosion of Square Elbow Based on Orthogonal Test

采用正交试验和数值模拟相结合的方法,研究了90°弯管在液固两相流条件下,管径(A)、入口流速(B)、液体流向(C)、砂粒直径(D)和砂粒质量流量(E) 5个因素对弯管冲刷腐蚀行为的影响程度大小。结果表明:不同因素对弯管冲刷腐蚀影响的顺序为B>A>E>C>D。当B为5 m/s、A为30 mm、E为0.03 kg/s、C液体流向为水平竖直向上、D为500μm时,冲蚀速率达到最大,冲蚀速率较大的区域集中在弯管轴向角度60°到90°之间,径向角度180°附近,即位于弯管外侧靠近出口处,实验结果也验证了此种工况下弯管外侧出口处的腐蚀速率更高,同时最优因素水平试验结果也表明:降低入口流速和增大管径能大幅度降低冲蚀速率。

Marine seawater pipeline and various fittings play an important role in cooling and firefighting, among which square elbow is widely used. However, it is found from daily maintenance that the square elbow is also the part mostly prone to leakage. In this paper, the effect of related parameters for pipe, such as diameter(A), inlet velocity(B), liquid flow direction(C), sand diameter(D) and sand mass flow(E) on the erosion-corrosion behavior of square elbow in the condition of liquid-solid two-phase flow was studied by means of orthogonal test and numerical simulation. The results show that the order of influence of different factors on erosion-corrosion of square elbow may be ranked as: B>A>E>C>D. The erosion rate of the square elbow reaches the maximum in case that B is 5 m/s, A is 30 mm, E is 0.03 kg/s, C is the flow direction horizontal and vertical upward, and D is 500 μm respectively. The area with large erosion rate is concentrated in the range between 60° and 90° of the axial angle of the elbow,whilst near 180° of the radial angle, i.e., where located on the outside of the elbow near the exit. The experimental results also verify that the corrosion rate on the outside of the elbow near the exit is higher in this working condition. At the same time, the results of tests by factors of optimal level also show that reducing the inlet velocity and increasing the pipe diameter can greatly reduce the erosion rate.