凹坑非光滑表面减阻技术数值模拟研究

NUMERICAL SIMULATION STUDYONDRAGREDUCTIONTECHNOLOGYOF NON-SMOOTHSURFACEOF PIT

对于管道输送,减小输送阻力消耗十分重要。对于减小输送阻力消耗,应用非光滑表面减阻技术尤为关键。利用流体力学知识,通过使用数值模拟软件,建立凹坑理论模型,以RNG k-ε模型为基础进行分析,模拟计算了光滑表面和矩阵排布的凹坑表面。将两种表面流场分别进行数值模拟,得到不同的减阻效果。通过计算分析可以得出,在不同速度下,发现h=0.05 mm的凹坑表面的减阻效果较好;针对12 m·s-1工况下的凹坑表面进行分析,其平均剪切力小于光滑表面,说明凹坑内部的流体在压力差的作用下,产生低速旋流气体,促进主流区域流动,进而减小总阻力。

For pipeline transportation,it is very important to reduce the transportation resistance consumption. In order to reduce the transportation resistance consumption,the application of non-smooth surface drag reduction technology is particularly important. By using the fluid mechanics knowledge and the numerical simulation software,establishing a pit theoretical model.The smooth surface and the pit surface with matrix arrangement were simulated and calculated based on the RNG k-ε model. Two kinds of surface flow fields were simulated respectively,and different drag reduction effects were obtained. Through calculation and analysis,we can conclude that under different working conditions,the surface of the pit with h = 0. 05 mm is better in drag reduction;analyzing the pit surface under 12 m·s-1 conditions,the average shear force is smaller than the smooth surface. Under the pressure difference,the fluid inside the pit generates a low-speed swirling gas,promotes the flow in the main flow region,and further reduces the total resistance.