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Study of Chaotic Rapid Variation of Heat and Fluid Flow in Porous Media

多孔介质中热量和流体流动的混沌快速变化研究

基本信息

批准号：
13650229
负责人：
MASUOKA Takashi
金额：
$ 2.62万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650229/
关键词：
Porous media Chaos Unsteady Effective heat capacity 乱流

项目摘要

The local volume-averaging technique has been applied theoretically so far to formulate the governing equations to describe transport phenomena in porous media. However, the application of this local volume-averaging technique to highly quick transient heat-transfer and fluid-flow phenomena may fail to consider the effect of the finite heat capacity of microscopic solid matrices of porous media with the respect of the time response in inhomogeneous temperature distributions, since the transient conduction of fluctuations is limited to the surface of the solid phase but not to the entire volume of the solid structures, where only the part of the heat capacity will be involved with relevance to the time constant of the transient phenomena. Recent trends of the applications with complicated microscopic flow passages will require the elucidation of the detailed theoretical framework of the basic transient heat and fluid flow description in chaotic and turbulent regimes, taking account of t … More he two types of vortices, i.e., pseudo vortex to reflect the thermal dispersion with representative scale of the microscopic porous structures and interstitial vortex to reflect the Forchheimer resistance with the representative scale gap width.The present study, adopting a bank of tubes in a narrow Hele-Shaw gap as a model of a porous medium, made an experimental and numerical analysis on microscopic velocity and temperature fluctuations, (1) clarifying temperature fields in microscopic solid structures with particular attention on the penetrating scale in the concept of the effective heat capacity for high-speed temperature variations, and (2) examining a new governing equation from the viewpoint of time dependent local volume-averaging of microscopic temperature fields. Then a new modeling to describe the transient heat transfer and fluid flow characteristics with the concent of partial was discussed.Although it has been widely accepted so far that the entire heat capacity of the microscopic porous structures contributes to the time response to the transient heat transfer, the present study suggests the need of a new approach to formulate the macroscopic energy equation, which is to be applied to the system with inhomogeneity with temperature difference between solid and fluid phases. Less

到目前为止，局部体积平均技术已经在理论上应用于制定控制方程来描述多孔介质中的输运现象。然而，这种局部体积平均技术在快速瞬态传热和流体流动现象中的应用可能未能考虑多孔介质的微观固体基质的有限热容量对非均匀温度分布中的时间响应的影响，由于波动的瞬时传导限于固相的表面而不是固体结构的整个体积，其中仅涉及与瞬态现象的时间常数相关的热容部分。近年来，在复杂微观流道的应用中，需要阐明混沌和湍流区域中基本瞬态热和流体流动描述的详细理论框架，并考虑到流体流动的复杂性。 ...更多信息两种类型的涡流，即，以窄缝间隙中的管束为多孔介质模型，对多孔介质中的微观速度和温度脉动进行了实验和数值分析，（1）阐明了微观固体结构中的温度场，特别注意了高速温度变化的有效热容概念中的穿透尺度;（2）从微观温度场的时间相关局部体积平均的观点考察了一个新的控制方程。在此基础上，提出了一种新的描述瞬态传热和流体流动特性的模型，该模型考虑了局部的影响，虽然目前普遍认为微观多孔结构的整体热容对瞬态传热的时间响应有贡献，但本文的研究表明，需要一种新的方法来建立宏观能量方程，适用于具有固液两相温差的非均匀体系。少