Heat Transfer: Conduction, Convection, and Radiation
FLUID MECHANICS and HEAT
TRANSFER (FMHT)
L. E. College, Morbi-2
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Prepared by Prof. Divyesh B. Patel
Mechanical Engg. Dept
LE. College, Morbi
+919925282644
divyesh21dragon@gmail.com
Heat Transfer
•
Heat always moves from a hot (warmer) place
to a cold (cooler) place.
•
Hot objects in a cooler room will cool to room
temperature.
•
Cold objects in a warmer room will heat up to
room temperature.
Question
•
If a cup of coffee and a ice were left on the
table in the room what would happen to them?
Why?
•
The cup of coffee will cool until it reaches
room temperature. The ice will melt and then
the water will warm to room temperature.
How is Heat Transferred?
There are THREE ways heat can move.
–
Conduction
–
Convection
–
Radiation
Conduction
•
Heat is transferred from one particle of matter
to another in an object without the movement
of the object.
•
Conduction = CONTACT
Conduction
•
When you heat a metal strip at one end, the heat travels to the other end.
•
As you heat the metal, the particles vibrate, these vibrations make the adjacent
particles vibrate, and so on and so on, the vibrations are passed along the metal and
so is the heat. We call this?
Conduction
•
Metal is a conductor, wood is an insulator. Metal conducts the
heat away from your hands. Wood does not conduct the heat
away from your hands as well as the metal, so the wood feels
warmer than the metal
.
Why does metal feel colder than wood, if they are
both at the same temperature?
Convection
•
Convection is the movement that transfers heat
within fluids and air (gas) Heat is transferred by
currents within the fluid or gas
•
Convection = VENTS
(through air and liquid particles)
•
Convection moves in a circular pattern
Convection
What happens to the particles in a liquid or a gas
when you heat them?
The particles spread out and become less
dense.
This effects fluid movement.
What is a fluid?
A liquid or gas.
RADIATION
•
Radiation is the transfer of energy by
electromagnetic waves
•
Radiation does NOT require matter to transfer
thermal energy
•
Radiation = Radiates
(heat escaping the sun)
Radiation May Come From Other
Sources
•
Have you ever sat too close to a campfire
while cooking marshmallows? You
’
re
enjoying the warmth ….. only to notice that
your skin is really warm?
Examples of RADIATION
1.
Fire
2.
Heat Lamps
3.
Sun
Heat transfer is a fundamental process that occurs through conduction, convection, and radiation. Conduction involves the transfer of heat between particles through direct contact, while convection moves heat within fluids and gases through currents. Radiation is heat transfer through electromagnetic waves. This explanation explores how heat is transferred and why certain materials feel colder or warmer than others at the same temperature.
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Presentation Transcript
FLUID MECHANICS and HEAT TRANSFER (FMHT) L. E. College, Morbi-2 Industrial Engineering Department Chapter-07 Conduction Prepared by Prof. Divyesh B. Patel Mechanical Engg. Dept LE. College, Morbi +919925282644 divyesh21dragon@gmail.com
Heat Transfer Heat always moves from a hot (warmer) place to a cold (cooler) place. Hot objects in a cooler room will cool to room temperature. Cold objects in a warmer room will heat up to room temperature.
Question If a cup of coffee and a ice were left on the table in the room what would happen to them? Why? The cup of coffee will cool until it reaches room temperature. The ice will melt and then the water will warm to room temperature.
How is Heat Transferred? There are THREE ways heat can move. Conduction Convection Radiation
Conduction Heat is transferred from one particle of matter to another in an object without the movement of the object. Conduction = CONTACT
Conduction When you heat a metal strip at one end, the heat travels to the other end. As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on and so on, the vibrations are passed along the metal and so is the heat. We call this? Conduction
Why does metal feel colder than wood, if they are both at the same temperature? Metal is a conductor, wood is an insulator. Metal conducts the heat away from your hands. Wood does not conduct the heat away from your hands as well as the metal, so the wood feels warmer than the metal.
Convection Convection is the movement that transfers heat within fluids and air (gas) Heat is transferred by currents within the fluid or gas Convection = VENTS (through air and liquid particles) Convection moves in a circular pattern
Convection What happens to the particles in a liquid or a gas when you heat them? The particles spread out and become less dense. This effects fluid movement. What is a fluid? A liquid or gas.
RADIATION Radiation is the transfer of energy by electromagnetic waves Radiation does NOT require matter to transfer thermal energy Radiation = Radiates (heat escaping the sun)
Radiation May Come From Other Sources Have you ever sat too close to a campfire while cooking marshmallows? You re enjoying the warmth .. only to notice that your skin is really warm?
Examples of RADIATION 1. Fire 2. Heat Lamps 3. Sun
