INTERNAL ENERGY

Involves all molecular activity and viewed as the sum of the kinetic and potential energies of the molecules.

INTERNAL ENERGY

nvolves all molecular activity and viewed as the sum of the kinetic and potential energies of the molecules.

SENSIBLE HEAT

When the heat transferred to a matter results to an

increase of its temperature.

LATENT HEAT

When there is too much molecular movement

between molecules, a phase change occurs.

ENTHALPY

Involves the internal energy and the flow energy of

a fluid.

SPECIFIC HEAT

The energy required to raise the temperature of a unit

mass of a substance by one degree

HEAT FLOW

Transfer of thermal energy

HEAT FLUX

It is the rate of heat

transfer per unit area

normal to the direction

of heat transfer.

Heat generation

conversion of nuclear, chemical,

mechanical, and electrical energies into thermal

energy for simple calculations

FLUID FLOW

A fluid flowing through a pipe or duct can be approximated as

one-dimensional.

conduction

convection

radiation

Heat Transfer Mechanisms are:

CONDUCTION

Transfer of energy from the more

energetic particles, to the

adjacent less energetic ones.

JEAN FOURIER

French mathematician and

physicist.

 Best known for his infinite

series of trigo. functions and

theory of heat conduction.

THERMAL CONDUCTIVITY

Rate if heat transfer through a unit thickness of the

material per unit temperature difference.

 The material’s ability to conduct heat.

TEMPERATURE GRADIENT

Heat is conducted in the direction of decreasing

temperature (2nd Law of Thermodynamics)

CONVECTION

Energy transfer

between a solid

surface, and the

adjacent fluid

(liquid or gas).

fluid motion

enhances heat transfer.

NATURAL CONVECTION

Cooling a hot brick by blowing cool air over its surface.Heat is carried away by fluid

motion.Hotter air molecules are

replaced by cooler air

molecules.

Forced Convection

Fluid is forced over the surface by

means of a fan, pump, or the

wind.

RADIATION

does not require any

material medium to

transfer heat. In fact it can

transfer heat at the speed

of light in a vacuum.

james maxwell

THEORETICAL FOUNDATION OF

RADIATION

Gamma rays

produced by nuclear reactions.

X-rays

bombardment of metals with high-energy

electrons.

microwaves

excitation of klystrons and magnetrons

radio waves

excitation of flow of alternating current

through electric conductors