摘要
该文针对在水中添加阳离子表面活性剂产生的减阻作用同时降低传热性能的现象,应用相位多普勒激光测量系统和热电偶温度测量系统对二维流道内表面活性剂减阻流体热边界层内的湍流温度脉动以及传热特性进行了实验研究。研究表明,表面活性剂减阻流体平均温度梯度在流动缓冲层很大,热扩散率较低,而水的热阻主要发生在近壁区域的高扩散层。表面活性剂减阻流体温度脉动强度与速度脉动强度有相似的分布趋势,其峰值都向外层移动。在近壁处的高扩散层温度脉动频率很小,而在平均温度梯度很大的低扩散层,减阻流体的温度脉动频率有所增强。而水的温度脉动频率比表面活性剂溶液高且在整个断面上几乎没有变化。对于表面活性剂热流体,湍流温度脉动对轴向热流量的贡献更大,使得轴向热流量的最大值出现在靠近温度脉动强度最大值所在的位置。表面活性剂减阻流体法向湍流热流量分布与雷诺应力分布有相似的趋势。
In this paper, the drag-reducing surfactant solution flows in a fully developed turbulent channel flow have been analyzed experimentally using Phase Doppler Anemometry and thermocouples in order to study the temperature fluctuations and heat transfer characteristics on the drag-reducing and heat transfer reduction phenomena of the surfactant solution flows. The experiment results show that the larger mean temperature gradient and smaller thermal diffusivity of the surfactant solution flows in the buffer layer while the main heat resistance of the water exits in the viscous sub-layer. The mean temperature fluctuations and velocity fluctuations have the similar tendency and the peak values are out of the wall. The temperature fluctuation frequency of the water is high compared to surfactant case. The frequency of temperature fluctuation is small and the characteristics of the temperature vary with the variation of distance from the wall for surfactant solution flows. Temperature fluctuation governs the stream-wise turbulent heat flux more than the velocity fluctuation does and the peak value of the stream-wise heat flux is located close to the peak of the temperature fluctuation. The profiles of wall-normal turbulent heat flux are similar to the Reynolds stress profiles for surfactant solution flow.
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2008年第1期42-47,共6页
Chinese Journal of Hydrodynamics
基金
国家自然基金资助项目(50476016)
国家自然科学基金国际合作项目(50611140359)
高等学校博士学科点专项科研基金资助课题(20030248032)
关键词
表面活性剂
减阻
温度脉动
湍流热流量
surfactant
drag-reducing
temperature fluctuation
turbulent heat flux
