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1. Real Lime Application of Heat & Mass Transfer
P M V Subbarao
Associate Professor
Mechanical Engineering Department
IIT Delhi
Understand Philosophy Through Experience……

2. The Bare Pentium 4 Processor

3. Heat Sinks for Pentium 4

4. Pentium 4 While Performing

5. Heat Transfer :: An Engineering Science
• The first law of thermodynamics establishes a relationship
between heat and work (Energy Interactions).
• The second law of thermodynamics states that the
spontaneous energy interactions are unidirectional.
• Thermodynamics is totally silent on the question the rate at
which heat travels.
• How to control the rate of heat transfer?
• Heat Transfer is an Engineering science to design thermal
infrastructure.
• It evolved over 200 years.

6. Applications of Mass Transfer

7. Mass Transfer
• Mass transfer: The transfer of mass into or out of a substance
• The transfer of a chemical compound from one phase to another
• Examples:
• Evaporation: liquid gas
• Diffusion: high concentration low concentration

8. Evaporation:
Drying
Concentration
Baking
Frying
Boiling
Various Mass Transfer Phenomenon
Diffusion:
Salt through cheese curd
Smoke through meat
Marinade or curing solution through meat
Lye in tomato peeling
Not mass transfer:
Moving a fluid from one place to another

9. Osmosis
• Osmosis is the net movement of water across a partially permeable
membrane from a region of high solvent potential to an area of low
solvent potential, up a solute concentration gradient.
• Osmosis is responsible for the ability of plant roots to suck up water
from the soil.
• Since there are many fine roots, they have a large surface area, water
enters the roots by osmosis, and generates the pressure required for the
water to travel up the plant.
• Osmosis can also be seen very effectively when potato slices are added
to a high concentration of salt solution.
• The water from inside the potato moves to the salt solution, causing the
potato to shrink and to lose its 'turgor pressure'.
• The more concentrated the salt solution, the bigger the difference in
size and weight of the potato slice.
• For example, freshwater and saltwater aquarium fish placed in water of
a different salinity than that they are adapted to will die quickly, and in
the case of saltwater fish, rather dramatically.

10. DIFFUSION OF 02 AND C02 ACROSS THE
ALVEOLAR-CAPILLARY MEMBRANE
• All gas movement in the lung occurs as a result of passive diffusion,
i.e., gas moves from one region to another only when the partial
pressure of gas is greater in one region than another.
• The transfer of gas from the alveolus to the blood occurs by simple
diffusion.
• The rate of transfer depends on what?

11. Desert Cooler

12. Evaporative Cooling
• Cooling through the evaporation of water is an ancient and
effective method of lowering temperature.
• Both plants and animals use this method to lower their
temperatures.
• Trees, through the process of evapotranspiration, for example,
remain cooler than their environment.
• People accomplish the same thing when they perspire.
• For both trees and people the underlying scientific principle is
the same: when water evaporates, that is, changes
from a liquid to a gas, it takes heat energy from the
surrounding environment, thus leaving its environment cooler.

13. Primitive Products
• Finally, some of us may have discovered that
water kept in a canvas bag, porous clay container,
or in a canteen with a water-soaked cloth cover, is
much cooler, especially on a hot day, than water
kept in plain metal or plastic containers.
• As the water evaporates from the surfaces of these
containers it draws heat away from the containers
and the water they hold, as well as from
the air around them, thus leaving the water cooler.

14. Syllabus
• Introduction :3 Lecture
• Introduction to Heat Transfer; Relationship to
thermodynamics; Heat Transfer as an engineering
science; Practical relevance; Mechanisms of Heat
transfer: conduction, convection and radiation;
related parameters.
• Conduction Heat Transfer : 8 Lectures
• Heat Conduction equation and its approximations:
steady and unsteady, single and multidimensional,
constant and variable properties, with and without
heat generation. Steady state conduction; thermal
resistance networks in planar, cylindrical and
spherical systems; critical radius of insulation;
extended surface heat transfer; fin effectiveness and
efficiency; thermal insulation. Transient conduction
in semi-infinite and finite media; lumped capacitance
method. Introduction to numerical solution of heat
conduction equations.

15. • Diffusion Mass Transfer :3 Lectures
• Constitutive equations and definitions for
composition of binary mixtures; Fick's law of
diffusion and binary diffusion coefficient;
conservation equation for species; steady and
transient diffusion; analogy to conduction heat
transfer.
• Convection Heat Transfer :11 Lectures
• Mechanism of convection; analogy of heat,
momentum and mass transport in moving fluids;
th concept of transport in a boundary layer;
similarity, scaling laws and analogy between
momentum, heat and mass transfer; turbulence.
• External flows: flat plate in parallel flow;
cylinder in cross flow; applications. Internal
flows: concepts of mean velocity and mixing cup
temperature; hydrodynamically and thermally
fully developed and developing flows; energy
balance; circular tubes -- laminar and

16. • turbulent flows. Free convection: governing
parameters; external and internal flows; mixed
convection.
• Boiling and Condensation :3 Lectures
• Basic phenomena: boiling modes and boiling
curve; regimes in pool boiling; forced
convection boiling; regimes of flow for forced
convection boiling in a tube; condensation:
film and drop-wise condensation: applications.
• Heat Exchangers ;4 Lectures
• Heat exchanger types; definition of overall
heat transfer coefficient; heat exchanger
analysis: rating and sizing of heat exchangers;
Log mean temperature difference method; Number
of Transfer Units – effectiveness method;
compact heat exchangers.

17. • Radiation Heat Transfer :10 Lectures
• Basic concepts and definitions:
Intensity, emissive power,
irradiationand radiosity; black body
radiation and spectral dependence of
emissive power; emissivity absorptivity
and reflectivity; Kirchhoff's law; gray
and diffuse surfaces; Radiative
Exchange: view factor; black body
radiation exchange; exchange between
gray, diffuse surfaces; gas radiation;
radiation combined with conduction and
convection.

18. BOOKS
• Fundamentals of Heat and Mass
Transfer (Fifth edition):
Incropera F.P. and De Witt, D.P.
• Heat Transfer -- a practical
approach Cengel Y.
• Heat Transfer (Ninth edition):
Holman J.P.
• Fundamentals of Heat & Mass
Transfer: M. Thirumaleshwar.
• Heat Transfer: Kreith F. and Bohn

19. What is Heat Transfer?
• Thermal energy is related to the temperature of matter.
• For a given material and mass, the higher the temperature, the
greater its thermal energy.
• Heat transfer is a study of the exchange of thermal energy
through a body or between bodies which occurs when there is a
temperature difference.
• When two bodies are at different temperatures, thermal energy
transfers from the one with higher temperature to the one with
lower temperature.
• Heat always transfers from hot to cold.
• Heat is typically given the symbol Q, and is expressed in joules
(J) in SI units.
• The rate of heat transfer is measured in watts (W), equal to joules
per second, and is denoted by q.
• The heat flux, or the rate of heat transfer per unit area, is
measured in watts per area (W/m2), and uses q" for the symbol.