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

点击翻译按钮获取中文摘要

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