INTRODUCTION OF TRANSPORT PHENOMENA

INTRODUCTION OF TRANSPORT PHENOMENA

LEARNING OUTCOMES

CATEGORIES OF TRANSPORT PHENOMENA

ASSIGNMENT

DEFINITION

REFERENCES

LEARNING OUTCOMES

By the end of this course, you should be

able to:1) Understand the definition of transport

phenomena.2) Understand the three (3) types of

transport phenomena.3) Explain the mechanisms of transport

phenomena.

1) A transport phenomenon is any of various mechanisms by which particles or quantities move from one place to another.

2) Includes 3 closely related topics: a) heat transfer – deals with the transport of energy.b) fluid dynamics – involves the transport of momentum.c) mass transfer – concerned with the transport of mass of various chemical species.

What are the transport phenomena?

There are three main categories of transportphenomena: TRANSPORT

PHENOMENA CATEGORIES

HEAT TRANSFER•Definition•Types•Example•Activity

MOMENTUM TRANSFER•Definition•Example•Activity

MASS TRANSFER•Definition•Example•Activity

1)Deals with the transfer of energy and difference in temperature is the driving force for the heat transfer.

2) The process of increasing the kinetic energy of a material's particles from a material of high temperature to one of lower temperature.

3) Once the material at the same temperature, no more energy can be transferred.

HEAT TRANSFER

Typical methods of heat transfer

CONDUCTION

The transfer of heat through solid objects e.g: touch something hot

RADIATION

The transfer of heat, in the form of electromagnetic energy, through space.

e.g: Expose to the sun – felt warmth

CONVECTION

The transfer of heat through liquids or gases

e.g: Heat from burner is transferred to the circulating water

Example: Molecular transport for conduction of heat from a high-temperature region to a low-temperature region through a metal rod, shown in Figure below. What happen to the metal rod after a few minute?

Flow Direction

rod

When metal heated on one end, will soon be hot on the other end too.

The hot molecules in the fire have more energy than the cooler molecules of the other end rod. As the molecules collide, energy is transferred from the hotter molecules to the cooler molecules.

CLICK THE VIDEO..

TRY YOURSELF!!!Which one of the following pictures is conduction, convection and radiation

transport?

ANSWER Which one of the following pictures is conduction, convection and radiation

transport?

Radiation

Conduction

Conduction

RadiationConvection

Radiation

OTHER EXAMPLES

MOMENTUM TRANSPORT1) Fluid flow is a simple example of momentum

transfer. The driving force for fluid flow is a pressure difference.

2) On a molecular scale that means that the molecules banging into each other transfer their momentum to other molecules.

3) On a larger scale, these molecules banging into each other determine how the fluid is going to flow that is, if it will just flow smoothly (laminar), or if it will be rough (turbulent).

Example: Water flow in a drinking fountain. What will happen if the valve in a drinking fountain is opened?

When the valve in a drinking fountain is opened, the water flows out in a jet because the water pressure inside the fountain is much higher than the atmospheric pressure into which the jet discharges.

CLICK THE VIDEO..

TRY YOURSELF!!!Explain the momentum transport for each

picture below:

MASS TRANSPORT

1) Mass transfer deals with the transfer of mass. Concentration is the driving force.

2) Once the concentration is the same everywhere, no more mass transfer can take place.

3) If you take a glass of water and put one drop of red dye in it. Even if you don't stir the water, eventually the water is all the same pinkish color.

Example: How the red dye spreads out in the water?

The red dye when it is first dropped into the water is at a high concentration and the water is at zero concentration. But, as the dye spreads out, the concentration of the dye slowly increases, until, it is all at the same low concentration everywhere. Once the concentration of the dye in the water is the same everywhere, no more mass transfer can take place.

TRY YOURSELF!!!Which one of the following pictures is NOT a

mass transfer? Explain..

How are they all related?

• They all are similar in their behaviour.

• They all move stuff (Momentum, Heat, or Mass) from a place where there is a lot of the “stuff” to a place where there is less “stuff”.

Analogist between all transport Phenomena

There is a driving force (momentum, temperature, or concentration difference or 'gradient'), which becomes smaller as time progresses, and eventually becomes zero when no more transfer of ‘stuff’ takes place.

Exercise…..

• Find ONE transportation applications for each phenomena in chemical engineering field. Explain.