Review Paper on Forced Convection Heat Transafer Augmentation Using Annular Blockages

Abstract

The study of improved heat transfer performance is

referred to as heat transfer enhancement,

augmentation, or intensification. In general, this

means an increase in heat transfer coefficient.

Energy- and materials-saving considerations, as well

as economic incentives, have led to efforts to produce

more efficient heat exchange equipment. Common

thermal-hydraulic goals are to reduce the size of a

heat exchanger required for a specified heat duty, to

upgrade the capacity of an existing heat exchanger, to

reduce the approach temperature difference for the

process streams, or to reduce the pumping power. The

study of improved heat transfer performance is

referred to as heat transfer enhancement,

augmentation, or intensification. In general, this

means an increase in heat transfer coefficient. [1]

General techniques for enhancing heat transfer can be

divided in three categories. One is passive method

such as twisted tapes, helical screw tape inserts,

rough surfaces, extended surfaces, additives for

liquid and gases. The second is active method, which

requires extra external power, for example

mechanical aids, surface fluid vibration, use of

electrostatic fields. Passive methods are found more

inexpensive as compared to other group.