Roger Prud'homme – författare

Reactive ?uids are present in many situations of great importance, such as in combustion chambers or around spacecraft re-entering the atmosphere. - alyzing the ?ow properties of such ?uids represents one of the most di?cult challenges to current technology. Indeed, all of the most di?cult aspects of ?uid mechanics appear to be grouped together in this research ?eld! Such ?uids are complex mixtures with compositions that vary rapidly in time and space. They are not usually at thermodynamic equilibrium, since the reaction times of the chemical reactions involved may not be negligible in comparison with the transit time of the ?uid. However, the author of this book limits its scope to typical phenomena that are not very far from local equilibrium but can nevertheless exhibit the most important types of irreversible processes. The production of entropy is highly dependent on the chemical reactionpa- way, which is di?cult to simplify. Also, most of the classical problems that characterize?uid mechanics—such as turbulence, the presence of thin bou- ary layers or shear layers, and the propagation of acoustic waves and shock waves—are also present, and are much more di?cult to analyze and describe than they are for homogeneous?uids, because reactive mixtures interact with these phenomena. For example, density is highly dependent on the chemical pathway since it is determined by the local and instantaneous production of chemical species, and so its value a?ects many other quantities through the equation of state and the balances of mass, momentum, and energy.

Interfaces are present in most fluid mechanics problems. They not only denote phase separations and boundary conditions, but also thin flames and discontinuity waves. Fluid Mechanics at Interfaces 1 focuses on the science of interfaces, in particular, using various scientific methods of analysis relating to space, speed and time. Our investigation takes us from the microscopic or small scale (starting with molecular and nanoscopic scales) to the macroscopic (including meso and interstellar scales), and also explores the laws of interfaces (classical mechanics, quantum mechanics and relativistic mechanics).Chapter 1 examines the questions raised by modeling interfaces in the presence of one or more fluid phases. Chapter 2 discusses the action of turbulence in liquid–vapor flows that contain both small, dispersed bubbles as well as large bubbles, with heat exchanges at the interfaces. In addition, a new model is presented, using large eddy simulation (LES). Chapter 3 studies an original method for calculating the drag force and thermal transfers in flows around networks of spherical particles, while Chapter 4 focuses on the relationships between interfaces and critical fluids.Chapter 5 examines shearing, which causes anomalies in the Brownian motion of particles in strongly fluctuating near-critical mixtures, and Chapter 6 introduces basic concepts related to combustion interfaces, raising the question of the combustion of solids, before ending with a brief presentation of the Rankine–Hugoniot theory and a historical overview of the research carried out in the field of combustion.

Interfaces are present in most fluid mechanics problems. They not only denote phase separations and boundary conditions, but also thin flames and discontinuity waves. Fluid Mechanics at Interfaces 2 examines cases that involve one-dimensional or bi-dimensional manifolds, not only in gaseous and liquid physical states but also in subcritical fluids and in single- and multi-phase systems that may be pure or mixed.Chapter 1 addresses certain aspects of turbulence in discrete mechanics, briefly describing the physical model associated with discrete primal and dual geometric topologies before focusing on channel flow simulations at turbulence-inducing Reynolds numbers. Chapter 2 centers on atomization in an accelerating domain. In one case, an initial Kelvin–Helmholtz instability generates an acceleration field, in turn creating a Rayleigh–Taylor instability which ultimately determines the size of the droplets formed. Chapter 3 explores numerical studies of pipes with sudden contraction using OpenFOAM, and focuses on modeling that will be useful for engines and automobiles.Chapters 4 and 5 study the evaporation of droplets that are subject to high-frequency perturbations, a possible cause of instabilities in injection engines. The Heidmann model, which replaces the droplets in motion in a combustion chamber with a single continuously-fed droplet, is made more complex by considering the finite conduction heat transfer phenomenon. Finally, Chapter 6 is devoted to a study of the rotor blade surface of a Savonius wind turbine, considering both a non-stationary and a three-dimensional flow.

Interfaces are present in most fluid mechanics problems. They not only denote phase separations and boundary conditions, but also thin flames and discontinuity waves. Fluid Mechanics at Interfaces 3 firstly positions models as relative to applications (i.e. pollution, drops for propulsion, wind power, etc.), then emphasizes the importance of social consequences.Chapter 1 examines the questions raised by simulation of a pollutant's concentration degradation in permanent 2D flow using the finite element method. Chapter 2 considers an approximate analytical solution for mixed injection regimes, which acts on drop vaporization frequency response. Chapter 3 examines the case of an incompressible external flow of uniform speed at infinity, leading the liquid in the drop by friction. Chapter 4 gives a summary of combustion-based weapons and their effects. Chapter 5 then looks at the shifting interface in spacetime. Chapter 6 limits itself to two key concepts: the first is that of capillary interfaces where surface tension is present even at equilibrium, the second is that of thin flames which only exist outside of equilibrium, but which can be considered as generalized interfaces. Chapter 7 challenges the idea of constituents of matter, leading to radically transforming chemistry. Chapter 8 is concerned by the modeling of partial wetting by macroscopic approach in discrete mechanics. Chapter 9 states a numerical method of finished differences, making it possible to calculate the variables describing an average flow. Chapter 10 considers circulation in the vessels of the human body. Chapter 11 contributes by generalizing the classical series solution for initial boundary value problems of the 1D reaction-diffusion equations on any finite interval of the real line.

The aim of this book is to relate fluid flows to chemical reactions. It focuses on the establishment of consistent systems of equations with their boundary conditions and interfaces, which allow us to model and deal with complex situations.Chapter 1 is devoted to simple fluids, i.e. to a single chemical constituent. The basic principles of incompressible and compressible fluid mechanics, are presented in the most concise and educational manner possible, for perfect or dissipative fluids. Chapter 2 relates to the flows of fluid mixtures in the presence of chemical reactions. Chapter 3 is concerned with interfaces and lines. Interfaces have been the subject of numerous publications and books for nearly half a century. Lines and curvilinear media are less known Several appendices on mathematical notation, thermodynamics and mechanics methods are grouped together in Chapter 4.This summary presentation of the basic equations of simple fluids, with exercises and their solutions, as well as those of chemically reacting flows, and interfaces and lines will be very useful for graduate students, engineers, teachers and scientific researchers in many domains of science and industry who wish to investigate problems of reactive flows. Portions of the text may be used in courses or seminars on fluid mechanics.

Flows with chemical reactions can occur in various fields such as combustion, process engineering, aeronautics, the atmospheric environment and aquatics.The examples of application chosen in this book mainly concern homogeneous reactive mixtures that can occur in propellers within the fields of process engineering and combustion: propagation of sound and monodimensional flows in nozzles, which may include disequilibria of the internal modes of the energy of molecules;ideal chemical reactors, stabilization of their steady operation points in the homogeneous case of a perfect mixture and classical instruments of experimental and theoretical analysis such as population balances, and the distribution of residence and passage times;laminar and turbulent flames, separating those which are premixed from those which are not and which do not exhibit the same mechanisms, but which also occur in the case of triple flames.Flows and Chemical Reactions in Homogeneous Mixtures provides information on dimensional analysis, statistical thermodynamics with coupling between internal modes and chemical reactions, the apparition and damping of fluid turbulence as well as its statistical processing, bifurcations, flames in a confined medium and diffusion.

This book - a sequel of previous publications 'Flows and Chemical Reactions' and 'Chemical Reactions in Flows and Homogeneous Mixtures' - is devoted to flows with chemical reactions in heterogeneous environments. Heterogeneous media in this volume include interfaces and lines. They may be the site of radiation. Each type of flow is the subject of a chapter in this volume.We consider first, in Chapter 1, the question of the generation of environments biphasic individuals: dusty gas, mist, bubble flow. Chapter 2 is devoted to the study at the mesoscopic scale: particle-fluid exchange of momentum and heat with determination of the respective exchange coefficients. In Chapter 3, we establish simplified equations of macroscopic balance for mass, for the momentum and energy, in the case of particles of one size (monodisperse suspension). Radiative phenomena are presented in Chapter 5.

This book - a sequel of previous publications Flows and Chemical Reactions, Chemical Reactions Flows in Homogeneous Mixtures and Chemical Reactions and Flows in Heterogeneous Mixtures - is devoted to flows with chemical reactions in the electromagnetic field.The first part, entitled basic equations, consists of four chapters. The first chapter provides an overview of the equations of electromagnetism in Minkowski spacetime. This presentation is extended to balance equations, first in homogeneous media unpolarized in the second chapter and homogeneous fluid medium polarized in the third chapter. Chapter four is devoted to heterogeneous media in the presence of electromagnetic field. Balance equations at interfaces therein.The second part of this volume is entitled applications. It also includes four chapters. Chapter five provides a study of the action of fields on fire. Chapter six deals with a typical application for the Peltier effect, chapter seven is devoted to metal-plasma interaction, especially in the Langmuir probe and finally Chapter Eight deals with the propulsion Hall effect.Are given in appendix supplements the laws of balance with electromagnetic field and described the methodology for establishing one-dimensional equations for flow comprising active walls as is the case in some Hall effect thrusters.