添加筛网增强减阻流体湍流特性的试验研究

Experimental Study on the Turbulence Enhancement toDrag-reducing Flow with Addition Mesh

应用粒子图象测速仪对添加筛网后的CTAC(CetyltrimethylAmmoniumChloride)减阻流体湍流流场进行试验研究,得到了在筛网后不同位置的减阻流体湍流速度分布和平均速度分布。研究表明:在靠近筛网处,减阻流体的平均速度分布趋向于和水的速度平均分布相一致,而在远离筛网处,其平均速度分布趋向于减阻流体不加筛网时的平均速度分布;在筛网附近,CTAC减阻流体湍流核心区明显增大,在近壁面处出现强烈的漩涡波动,瞬间速度空间分布趋近于水的速度空间分布,在远离筛网处,CTAC减阻流体过度层明显增厚,在湍流核心区和过度层之间出现小漩涡,这表明被金属筛网破坏的胶束重新缔合成棒状胶束,恢复了减阻性能。

The turbulence characteristics of a surfactant solution in changing from drag-reducing flow to turbulent flow inside two-dimension smooth channel and in changing from mesh plug were investigated through PIV (Particle Image Velocimetry) system in this study. It is concluded that the mean velocity profiles of the surfactant solution are similar to that of the water near the mesh plug, whereas the mean velocity profile of the surfactant solution far from the mesh is consistent to that of the surfactant solution flow in smooth channel. The size of the core region of the surfactant solution is obviously larger near the mesh plug, and there are intense eddies near the wall. For the bubble micelle is assembled to the rod-like micelle, with the result of thickening the intergrades region and of suppressing the formation of the large eddies far from the mesh plug.