摘要:
采用实验的方法,测试了黄原胶溶液在不同直径的光滑管道流动中的减阻特性和管径效应。其中变化参数为:(1)管道直径,共有3种管径,分别为5、10和20mm;(2)黄原胶溶液的浓度,变化范围为50~550 ppm;(3)流速,用广义雷诺数(ReM)来表征,变化范围为0~50000。实验测量了不同参数下的管道压降Δp和体积流量Q,得到了黄原胶溶液浓度与减阻率的关系,以及ReM 数对沿程阻力系数λ的影响,观测到黄原胶溶液减阻具有很明显的浓度效应,即随着溶液浓度的升高减阻率不断增大,直至达到最佳饱和减阻浓度,减阻率基本保持恒定。还观测到黄原胶溶液在不同管径中高低流速下表现出减阻类型的差异。
Abstract:
Experimental study on drag reduction characteristics of xanthan gum solution in smooth pipes with different diameters has been conducted.The variable parameters are as fol-lows:(1)the pipe diameters,5,10 and 20mm,respectively;(2)the concentration of xanthan gum solution ranging from 50 to 550ppm;(3 )fluid velocity,characterized by flow generalized Reynolds number in the range of 0~50000.The pipe pressure dropΔp and flow volume flux Q under different conditions have been measured.The relationship between drag reduction and con-centration of xanthan gum solution is obtained,and the influence of Reynolds number on friction factorλis also investigated.It is observed that the drag reduction effect of xanthan gum solution relys obviously on the concentration of the solution,percent drag reduction increasing with the increase of xanthan gum solution concentration until it reaches the optimum saturation concentra-tion where the percent drag reduction is mainly keeping constant.The experimental results also show the drag reduction type difference under low and high Reynolds number flow conditions for xanthan gum solution in three pipes with different diameters.
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