采气管线浮动式球阀迎流面的冲蚀进化特性

Characters of erosion evolution on upstream surface of floating ball valves used in gas flow line

基于冲蚀实验和数值模拟,采用3D成像技术、动网格方法研究了典型开度30%时浮动式球阀迎流曲面的冲蚀进化,提出了能概括各因素随时间变化的冲蚀进化模型.结果表明,冲蚀过程中严重磨损区域（迎流面中部B,E和H处）冲蚀速率呈降低趋势,用250 kg粉尘冲蚀后冲蚀速率为减薄前的0.9倍,用350 kg粉尘冲蚀后冲蚀速率为减薄前的0.825倍,用450 kg粉尘冲蚀后冲蚀速率为减薄前的0.755倍;在流速980 m/s,粉尘粒径35500mm和体积浓度1.6×10^–13-5.7×10^–6的球阀阀芯迎流面冲蚀下,冲蚀进化模型计算值与实验值的误差小于20%;流速1980 m/s、粉尘粒径150230mm和体积浓度1.68×10^–7-2.6×10^–5且几何模型与球阀迎流曲面不相似时,可将预测值和实验值控制在同一数量级.

The erosion evolution phenomenon usually renders the erosion model unable to accurately calculate the dynamic change of the wall thickness. Based on an erosion experiment and numerical simulation, the erosion evolution on the upstream surface of floating ball valves with 30% opening was described using 3D imaging and moving grid techniques. An erosion evolution model that can summarize the temporal variation of each factor was proposed. The resulting erosion rate in the severely eroded area（points B, E and H in the middle portion of the upstream surface） showed a decreasing trend during erosion. The erosion rate was 0.9 times that prior to surface thinning after 250 kg sand load and was 0.825 times and 0.755 times that after 350 kg sand load and 450 kg sand load, respectively. The error of the erosion evolution model when applied to the erosion of the ball valve core upstream was less than 20% under a flow velocity of 980 m/s, sand particle size of 35-500 μm, and volume concentration of 1.6×10^–13 to 5.7×106–6. When the erosion evolution model was applied to 19-80 m/s flow velocity, 150-230 μm sand particle size, and 1.68×10^–7 to 2.6×10^–5 volume concentration and with the geometrical model dissimilar to the ball valve upstream surface curvature, the prediction value can be controlled within the same order of magnitude as the experimental value.