摘要
当流体流过纵向涡发生器时,会在纵向涡发生器后产生沿纵向移动的涡旋,这些纵向涡的强烈运动,促进了主流区与传热壁面附近的流体搅混,削薄或破坏边界层,实现了强化传热。在窄间隙矩形通道内的加热板上布置矩形块的纵向涡发生器,通过正面450 mm×40 mm和侧面3 mm宽的石英玻璃可视窗内对纵向涡作用下的汽泡行为进行了可视化研究。通过分析纵向涡对单个汽泡、多个汽泡和汽泡演化作用特性的影响,表明纵向涡对汽泡产生了强烈的扰动作用,抑制了汽泡在加热板上的长大和聚集,加强了近壁区热流体和流道中央区冷流体之间质量、动量和能量的交换,对加热板表面的热边界层起到破坏和削薄作用,从而使汽液二相工况下的传热明显强化。由于纵向涡发生器作用距离远、结构简单,对平面或近似平面的窄间隙换热结构,具有良好的应用前景。
The so-called Longitudinal Vortex is a kind of vortex motion which is produced when the fluid flows over a Longitudinal Vortex Generators in a flow field, its swirling axis parallels to the direction of main flow, which can move ahead swirly around the main flow direction and exhibits a strong three-dimensional characteristics. As the fluid is mixed strongly between main flow and near the heat-plate, and the thermal boundary layer is greatly damaged and reduced by Longitudinal Vortex, the heat transfer is enhanced. The block Longitudinal Vortex Generators was used on the heat-plate in narrow rectangular channel. The visual study on bubbles was done by Longitudinal Vortex from 450 mm × 40 mm and 3 mm width quartz glass windows. Based on the analysis of single bubble, several bubbles and bubble evolution by Longitudinal Vortex, it concludes that the bubbles are affected intensely by Longitudinal Vortex. The growth and gathering of bubbles are depressed, and the momentum and energy exchange between cold and hot fluid are strengthened. The heat transfer enhancement by Longitudinal Vortex is obvious because the thermal boundary layer is greatly damaged and reduced. With relative long influence distance and simple structure, the Longitudinal Vortex Generators can be used in plate type and other narrow channels with flat surface.
出处
《化学工程》
CAS
CSCD
北大核心
2012年第7期46-51,共6页
Chemical Engineering(China)
基金
2005年度国家自然科学基金资助项目(50576089)
2006年度空泡物理和自然循环国家级重点实验室基金资助项目(9140C7101030602)
关键词
工程热物理
汽泡
可视化
纵向涡
窄间隙矩形通道
engineering themophysics
bubble
visual
longitudinal vortex
narrow rectangular channel
