Flow Visualization and Heat Transfer Characteristics for Sphere-Packed Pipes
Flow Visualization and Heat Transfer Characteristics for Sphere-Packed Pipes
复制标题
球填充管道的流动可视化和传热特性
DOI：
10.2514/1.30141
复制
发表时间：
2006
影响因子：
2.1
通讯作者：
A. Sagara
中科院分区：
文献类型：
--
作者：
K. Yuki;Masumi Okumura;H. Hashizume;S. Toda;N. Morley;A. Sagara
以碘化钠溶液为工质，采用匹配折射率法对球形填充管内复杂流动结构进行了粒子图像测速可视化研究。确定了管内具有代表性的三种流动结构：壁面效应导致高流速的弯曲型旁路流动，两对不稳定的孪生涡伴着强烈的撞击流到管壁，以及从管道中心区喷出的流动。在以水为工质的换热实验中，利用热电偶和红外热像测量了壁面温度分布，揭示了流动结构与局部换热性能之间的关系。虽然球体与加热壁接触点处的滞流形成了壁温较高的区域，但高速绕流和绕流与球体的碰撞效应对滞流区的热传递有显著影响。另一方面，在球体上、下游间隙较大的区域，由于有较强的碰撞流和绕流产生的涡流的影响，球体的换热性能较高。
Particle image velocimetry visualization to identify the complex flow structures in a sphere-packed pipe is carried out by using a matched refractive-index method with a sodium iodide solution as the working fluid. The following three flows were confirmed as representative flow structures in the pipe: a meandrous bypass flow with a high-flow velocity due to the wall effect, two pairs of unstable twin vortices accompanied by a strong impinging flow to the pipe wall, and a spouting flow from the central area of the pipe. In an experiment on heat transfer using water as the working fluid, the wall-temperature distribution is measured with thermocouples and infrared thermography, which makes clear a relation between the flow structures and the local heat transfer performance. Though an area with a high wall temperature is formed by the flow stagnation located at a contact point between the sphere and the heating wall, the colliding effect of the high velocity and of the meandrous bypass flow with the spheres significantly affects the heat transport from the stagnation areas. On the other hand, the heat transfer performance is quite high in a large gap area between the upstream and downstream spheres because of the influence of the strong impinging flow and the vortices that are both induced by the meandrous bypass flow.
流式细胞术分析胃癌患者腹腔内免疫细胞
DOI：
--
发表时间：
2022
期刊：
影响因子：
--
作者：
髙橋和也;大澤英之;金丸理人;倉科憲太郎;齋藤心;山口博紀;細谷好則;北山丈二,佐田尚宏
通讯作者：
北山丈二,佐田尚宏