权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study on the control of longitudinal dispersion in oscillatory flows in pipes and on the presentation method of its phenomena

管道内振荡流纵向频散控制及其现象的表示方法研究

基本信息

批准号：
10650173
负责人：
INABA Takehiko
金额：
$ 1.66万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650173/
关键词：
pipe flow oscillatory flow heat transfer enhancement pipe bundles pipe with wavy wall phase lag

项目摘要

Longitudinal heat transfer between two fluid reservoirs of different temperature is highly enhanced by fluid pulsation in capillary pipes that connect the reservoirs. The heat transfer is known to be proportional to the product of the longitudinal temperature gradient and the square of the pulsating fluid displacement from analyses for single circular pipes. Pipe bundles are used in practical applications to obtain a sufficient amount of heat transfer. There exist spaces between each three pipes in circular pipe bundles, which deteriorate the heat transfer characteristics. To avoid this disadvantage, pipes of triangular, square and hexagonal section as well as of circular on were considered. Although the triangular pipe showed the best heat transfer characteristics as a single pipe, it was cleared that the wall thickness and its heat conduction coefficient were important parameters to determine the performance as pipe bundles from the analysis under the conditions of the same cross sec … More tional area, wall thickness and fluid pulsation amplitude. The effect of wavy wall was also investigated changing the wave number of the wavy wall, its amplitude and the fluid pulsation frequency and amplitude. The heat transfer was enhanced with the amplitude of the wall waviness. The wavy wall pipes were superior to smooth ones in dynamic response of heat transfer controled by fluid pulsation amplitude and frequency.The mechanism of the heat transfer of this apparatus was investigated closely. We found a region where heat was transferred toward higher temperature end and this occurred in the region where the phase lag between the pulsations of fluid and temperature exceeded π/2. Then visualization methods have been investigated to explain these unseen phenomena to nonexperts including students as well as experts. It was found effective that each image should contain limited informations presented by primitive variables. The phase difference between the pulsations of fluid and temperature was most effectively presented by animations using wire frame model of different colors. The heat flow was obtained quantitatively solving the governing equations and expressed by the motion of virtual particles which represented enthalpy. The lateral motion of the particles was very subtle unlike the impressions given by the conventional qualitative explanation of the mechanism. The visualization method successfully showed that the small lateral motion of heat flow resulted in a significant enhancement of longitudinal heat transfer. Less

两个不同温度的储层之间的纵向换热是由连接储层的毛细管中的流体脉动增强的。从单个圆形管道的分析可知，传热与纵向温度梯度和脉动流体位移的平方的乘积成正比。管束在实际应用中用于获得足够的热量传递。在圆形管束中，三管之间存在空隙，使传热特性变差。为了避免这一缺点，考虑了三角形、方形和六边形截面以及圆形截面的管道。虽然三角形管作为单管表现出最好的换热特性，但在相同横截面条件下，壁厚及其导热系数是决定其作为管束性能的重要参数。研究了波纹壁对波纹壁波数、振幅、流体脉动频率和振幅的影响。换热随壁波振幅的增大而增强。在流体脉动幅值和频率控制下，波纹管壁传热的动态响应优于光滑管壁。对该装置的传热机理进行了深入的研究。我们发现在流体脉动与温度脉动之间的相位滞后超过π/2的区域，存在热量向较高温度端转移的区域。然后研究了可视化方法，向包括学生和专家在内的非专家解释这些看不见的现象。每个图像应该包含由原始变量表示的有限信息，这是有效的。采用不同颜色线框模型的动画最有效地呈现了流体和温度脉动之间的相位差。通过求解控制方程定量得到热流，并用代表焓的虚粒子运动来表示热流。粒子的横向运动是非常微妙的，不像对机制的常规定性解释所给的印象。可视化方法成功地表明，小的热流横向运动导致了纵向换热的显著增强。少