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Über dieses Buch

Transport phenomenain porous media are encounteredin various disciplines, e. g. , civil engineering, chemical engineering, reservoir engineering, agricul­ tural engineering and soil science. In these disciplines, problems are en­ countered in which various extensive quantities, e. g. , mass and heat, are transported through a porous material domain. Often, the void space of the porous material contains two or three fluid phases, and the various ex­ tensive quantities are transported simultaneously through the multiphase system. In all these disciplines, decisions related to a system's development and its operation have to be made. To do so a tool is needed that will pro­ vide a forecast of the system's response to the implementation of proposed decisions. This response is expressed in the form of spatial and temporal distributions of the state variables that describe the system's behavior. Ex­ amples of such state variables are pressure, stress, strain, density, velocity, solute concentration, temperature, etc. , for each phase in the system, The tool that enables the required predictions is the model. A model may be defined as a simplified version of the real porous medium system and the transport phenomena that occur in it. Because the model is a sim­ plified version of the real system, no unique model exists for a given porous medium system. Different sets of simplifying assumptions, each suitable for a particular task, will result in different models.



Chapter 1. Eight Lectures on Mathematical Modelling of Transport in Porous Media

The objective of this lecture is to set the stage and define the goals for this series of lectures. Accordingly, we shall start by defining a porous medium, understand what models are and why we need them to describe transport in porous media and discuss the modelling process. We shall concentrate on the class of models that visualize a porous medium domain as a continuum, or as a set of overlapping continua.
J. Bear

Chapter 2. Multiphase Flow in Porous Media

In this chapter, we consider the simultaneous flow of liquids and gases through porous media. We shall assume that cohesive forces in these fluids exceed the adhesion ones, and that the fluids are immiscible and separated from each other by stable abrupt interfaces. Air, water and oil are immiscible under normal conditions (atmospheric pressure, room temperature, etc.). This does not mean that solubility (or volatility) is zero, but that they are so small that a sharp interface forms and that the physical properties of the fluids are not affected.
Th. Dracos

Chapter 3. Phase Change Phenomena at Liquid Saturated Self Heated Particulate Beds

A wide variety of industrial, agricultural and energy production processes are related to the thermohydraulics of porous media saturated with multiple fluid phases. Examples include the drying of porous solids, the freezing of soils, the geothermal application, the thermally enhanced oil recovery, the heat transfer from buried pipelines, the design of heat pipes, the underground high level nuclear energy waste disposal and the Post Accident Heat Removal PAHR. This last application, addressing the nuclear safety analysis of Liquid Metal Fast Breeder and Light Water Reactors, is the main topic of the present chapter.
J-M. Buchlin, A. Stubos

Chapter 4. Heat Transfer in Self-Heated Particle Beds Submerged in Liquid Coolant

The PAHR (Post Accident Heat Removal) is conducted by the Joint Research Centre (JRC) of the European Communities at Ispra, Italy, within the framework of its nuclear reactor safety programme. It is one of the projects concerning fast breeder reactors.
Kent Mehr, Jørgen Würtz

Chapter 5. Physical Mechanisms During the Drying of a Porous Medium

The aim of this paper is to summarize the physical aspects of the drying process in order to model it.
Ch. Moyne, Ch. Basilico, J. Ch. Batsale, A. Degiovanni

Chapter 6. Stochastic Description of Porous Media

The definition of the properties of porous media in space can be made using the concept of random functions. This stochastic approach has two major advantages:
  • It conceptually defines the properties in space at a given point, without having to define a volume over which these properties must he integrated.
  • It provides means for studying the inherent heterogeneity and variability of these properties in space, and for evaluating the uncertainty of any method of estimation of their values.
G. De Marsily


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