摘要
针对在水中添加界面活性剂 (CTAC +NaSal)后 ,湍流流动阻力大幅度下降的现象 ,用激光多谱勒测速仪在二维水槽中对湍流特性进行了测量 ,研究并阐述了这种弱阻力湍流存在的条件 ,以及与雷诺数、温度、浓度的关系 ,得出了一些重要的结论 :添加界面活性剂的水溶液呈现弱阻力湍流的条件是流动雷诺数低于某个临界雷诺数 ;临界雷诺数随界面活性剂的浓度的增大而增大 ,随溶液的温度升高而减小 ;在弱阻力湍流流动中 ,主流速度曲线分布呈现明显的层流化 ,湍流强度明显减弱 ,雷诺应力几乎为零甚至出现亏损 ,这是湍流流动具有弱阻力的根本原因 ;在湍流脉动强度并未消失的情况下 ,雷诺应力却几乎为零 。
The phenomenon of drag reduction of turbulence water flow added with surfactant(CTAC+NaSal) was investigated experimentally in the work. The conditions of temperature, concentration of surfactant and Reynolds number that drag reduction may occur were studied. By using LDV,the turbulence properties of the flow in a two-dimensional channel were measured. It is concluded that the low drag of surfactant solution flow can be maintained at Reynolds numbers pertinent to turbulent flow of the case for water alone if the Reynolds number does not exceed a critical Reynolds number. The critical Reynolds number however increases with the concentration and decreases with the temperature of the solution. Under drag reducing flow, the main velocity profile shifts its shape to that of a laminar flow however, still remains certain level of turbulent intensities although quite weak than that of water flow under the same Reynolds number. While there are turbulent intensities, the turbulent Reynolds stress is almost zero or even has depletion, which reflects the change of correlation of turbulence intensities in different directions in the flow.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2001年第1期37-42,共6页
Journal of Xi'an Jiaotong University
基金
日本新能源产业技术综合研究与开发机构资助项目
