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Lecture 1Chapter 0
Introduction
27th January 2014
Total Marks 100Contact hrs: 3 per week
Text Book “Transport Phenomena”
by R. Byron Bird, Warren E. Stewart, Edwin N.
Lightfoot Second Edition
Course ContentsCh.E-407 TRANSPORT PHENOMENAViscosity and the mechanism of momentum transport;
Velocity distributions in laminar flow; The equations of change for isothermal systems; Velocity distribution with more than one independent variable
Thermal conductivity and mechanism of energy transport; Temperature distribution in solids and in laminar flow; The equations of change for non-isothermal systems
Diffusivity and the mechanisms of mass transport; Concentration distribution in solids and in laminar flow; The equations of change for multi-component systems.
What are Transport Phenomena?
Fluid Dynamics (transport of momentum)Heat Transfer (transport of energy)Mass Transfer (transport of mass)
Why Study Transport Phenomena?The 3 processes occur simultaneously in
industrial, biological and agricultural problems.
The basic equations are closely related.Mathematical tools used are similar.The molecular mechanisms in these are
nearly similar.
How to study Transport Phenomena?Study the transportation of momentum, heat,
mass through media as governed by various laws of nature.
Basic parameters representing the phenomena and nomenclature
Entity Being Transported/
Type of Transport
MOMENTUM ENERGY MASS
TRANSPORT BY MOLECULAR MOTION
VISCOSITY µ
Newton’s law of viscosity.Temperature, Pressure & Composition dependence on µKinetic theory of µ
THERMAL CONDUCTIVITY kFourier’s law of heat conduction Temperature, Pressure, and compositiondependence on k
Kinetic theory of k
DIFFUSIVITY DAB
Fick’s law of diffusionTemperature, Pressure, and composition dependence on DAB
Kinetic theory of DAB
TRANSPORT in LAMINAR FLOW or in SOLIDS, in ONE DIMENSION
SHELL MOMENTUM BALANCES
Velocity profilesAverage velocityMomentum flux at surfaces
SHELL ENERGY BALANCES
Temperature profilesAverage temperatureEnergy flux at surfaces
SHELL MASS BALANCES
Concentration profiles Average concentrationMass flux at surfaces
Continue…
Entity Being Transported
Type of Transport
MOMENTUM ENERGY MASS
TRANSPORT in an ARBITRARY CONTINUUM
EQUATION OF CHANGE (Isothermal)
Equation of continuityEquation of motion Equation of energy
EQUATION OF CHANGE (Non-isothermal)
Equation of continuity Equation of motion for forced and free convectionEquation of energy
EQUATION OF CHANGE (Multi-component)
Equation of continuity for each speciesEquation of motion for forced and free convectionEquation of energy
TRANSPORT IN LAMINAR FLOW or in SOLIDS, WITH TWO INDEPENDENT VARIABLES
MOMENTUM TRANSPORT
Unsteady viscous flowTwo-dimensional viscous flowBoundary-layer momentum transport
ENERGY TRANSPORT
Unsteady heat conductionHeat conduction in viscous flowTwo-dimensional heat conduction in solidsBoundary-layer energy transport
MASS TRANSPORT
Unsteady diffusionDiffusion in viscous flow Two-dimensional diffusion in solidsBoundary-layer mass transport
Continue…
Entity Being Transported
Type of Transport
MOMENTUM ENERGY MASS
TRANSPORT IN TURBULENT FLOW
TURBULENT MOMENTUM TRANSPORT
Time-smoothing of equation of changeEddy viscosity
Turbulent velocity profiles
TURBULENT ENERGY TRANSPORT
Time-smoothing of equation of changeEddy thermal conductivity
Turbulent temperature profiles
TURBULENT MASS TRANSPORT
Time-smoothing of equation of changeEddy diffusivity
Turbulent concentration profiles
TRANSPORT Between TWO PHASES
INTERPHASE MOMENTUM TRASNPORT
Friction factor f
Dimensionless correlations
INTERPHASE ENERGY TRASNPORT
Heat-transfer coefficient h
Dimensionless correlations (forced and free convection)
INTERPHASE MASS TRASNPORT
Heat-transfer coefficient kx
Dimensionless correlations (forced and free convection)
Continue…
Entity Being Transported
Type of Transport
MOMENTUM ENERGY MASS
TRANSPORT BY RADIATION
MOMENTUM TRANSPORT IN POLYMERIC LIQUIDS
Behavior of Polymeric LiquidsMolecular theories of polymeric liquidsRheometry
RADIENT ENERGY TRANSPORT
Planck’s radiation lawStefan-Boltzmann lawGeometrical problemsRadiation through absorbing media
MASS TRANSPORT IN MULTI-COMPONENT SYSTEMSConcentration diffusion and driving forceMass transfer across permeable membranesMass transfer in porous media
TRANSPORT IN LARGE FLOW SYSTEMS
MICROSOPIC BALANCES (Isothermal)
Mass balance Mechanical energy balance (Bernoulli equation)
MICROSOPIC BALANCES (Non-isothermal)
Mass balanceMomentum balance Mechanical and total energy balance
MICROSOPIC BALANCES (Multi-component)
Mass balance of each speciesMomentum balanceMechanical and total energy balance
THREE LEVELS OF STUDY OF TRANSPORT PHENOMENA1. Macroscopic Level2. Microscopic Level3. Molecular Level
Macroscopic Level
No attempt to understand the details of what is going on within the control volume
Mainly used for the global assessment of the problem
Integral Analysis
A Macroscopic Balance of1. Mass2. Momentum3. EnergyDue to various inputs & outputs from our control volume
Microscopic Level
An attempt to understand the details of what is going on within the control volume
Mainly used to get information of1. Velocity profiles2. Temperature profiles3. Concentration profiles
A Microscopic Balance of1. Mass2. Momentum3. EnergyDue to various inputs & outputs from our control volume
Differential Analysis
To understand the process and optimize it
Molecular Level
To seek the fundamental understanding of the process of1. Mass transfer2. Momentum transfer3. Energy transferIn terms of molecular structure & intermolecular forces
A job primarily for 1. Theoretical Physicists2. Physical ChemistSome times Engineers/applied scientists do get involved in cases of1. Complex molecules2. Extreme temperatures/pressures3. Chemical Reacting Flows
Each of these levels involve typical length scales
Molecular Level 1 to 1000 nanometers
Macroscopic Level Order of cm or m
Microscopic Level Micron to cm range
Requirements For Good Understanding Of This Subject
Physical Interpretation of key mathematical resultsGet into the habit of relating physical ideas to equations
Comparison of intuition and results obtained
MATHEMATICS, Differential Equations, Vectors, Calculus
Understanding of dimensional analysis
Division of BookChapters 1-8: Flow of pure fluids at constant
temperature (momentum transport)Chapters 9-16: Flow of pure fluids with
varying temperature (energy transport)Chapters 17-24: Flow of fluid mixtures with
varying composition (convective mass transport)