Transport Phenomena
David Andrés Gómez Ríos. Ch. Eng. MSc.
dandres.gomez@udea.edu.co
Content Summary
Introduction
Transport properties
Interfacial transport
Unit I – Mass Transport
Diffusivity and Mechanisms of Mass Transport
Mass Balance, Equations of change, Concentration
Distributions.
Unit II – Energy Transport
Thermal conductivity and mechanisms of energy
transport
Energy Balances, Equations of change in Non-
isothermal systems and Temperature Distributions.
Content Summary
Unit III – Momentum Transport
Viscosity and Mechanism of Momentum Transport
Newtonian and No Newtonian Fluids
Balance of Momentum, Equations of Change in
Isothermal Systems, Velocity Distributions
Introduction to Turbulent Flow
Unit IV – Analogies and combined transport
Cases studies of combined transport
Analogies mass-heat-momentum
Recommended Textbooks
Bird, Stewart, Lightfoot. “Transport Phenomena”. 2nd
Edition. John Wiley & Sons. 2002.
Heat & mass transport textbooks.
Fluids mechanics textbooks.
What is Transport Phenomena?
All processes generating change of properties exhibited by the
material under consideration.
These processes are irreversible and have statistical nature,
stemming from the random continuous motion of molecules,
mostly observed in fluids (liquids and gases).
What is Transport Phenomena?
Every aspect of transport phenomena is grounded in two
primary concepts:
The conservation laws: describe how the quantity being studied must
be conserved within the universe of the question.
Constitutive equations: describe how the quantity in question
responds to various stimuli via transport.
What is Transport Phenomena?
Difference with Thermodynamics: the approach.
Two points of view: microscopic one and macroscopic
one.
Integral analysis and differential analysis.
Reaching of equilibrium.
Transport phenomena studies non-equilibrium processes
involving momentum, heat, and/or species mass transfer in
fluid (liquid/gas) and solids.
What is Transport Phenomena?
Momentum Transfer: deals with the motion of a fluid as a
whole without considering its composition
Mass Transfer: deals with the movement of individual chemical
species within a fluid (or solid) relative to the motion of the
fluid as a whole.
Heat Transfer: deals with the laws governing movement of
thermal energy (heat) through a fluid or solid continuum.
Balances in Chemical Engineering
Chemical engineering is based in expressing the conservation
laws of nature in balances form.
The principal governing equations in transport phenomena are
conservation laws developed by applying momentum, energy,
and species mass balances to arbitrary, finite regions or
volumes of space.
In these property balances we need to appropriately quantify
the movement of specific material properties (momentum,
thermal energy, chemical species) across the boundaries or
surfaces of these arbitrary volumes
Mass transfer
The net motion of one
specie (molar or mass)
from one location to
another.
Stream
Phase
Fraction or
component
https://youtu.be/pu5SWO6sGo0
Mass transfer applications
Absorption
Evaporation
Drying
Precipitation
Membrane filtration
Distillation
Heat transfer
Concerns the exchange of thermal energy and heat
between physical systems.
Thermal conduction
Thermal convection
Thermal rad|iation
Transfer of energy by phase changes.
Heat transfer applications
Heat exchangers
Evaporation
Distillation
Ovens
Thermal insulation
Momentum transfer
The fluid is considered as a continuous distribution of
matter.
When a fluid is flowing in the x-direction parallel to a
solid surface, the fluid has x-directed momentum.
Hence the x-directed momentum has been transferred in
the z-direction from the faster- to the slower-moving
layer.
Momentum transfer application
Fluid transport
Aerodynamics
Energy generation
https://www.youtube.com/watch?v=22W753joAnA
Constitutive Equations
Heat transport: Fourier’s Law
Mass Transport: Fick’s Law
Newton’s Law: Momentum transport
k → Thermal conductivity
DAB → Mass (Molar) diffusivity
of A across B
μ → Viscosity
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