Fundamentals of Heat and Mass Transfer

Chapter 6

Heat Transfer from Extended Surfaces (FINS)

6.1 Introduction

In this chapter, we shall discuss heat transfer from extended surfaces, also called Fins.

Fins are generally used to enhance the heat transfer from a given surface.

Consider a surface losing heat to the surroundings by convection. Then, the heat transfer rate Q, is given by Newton’s Law of Cooling:

 

Q = hA_s(T_s - T),

 

where, h = heat transfer coefficient between the surface and the ambient

 

As	= exposed area of the surface
Ts	= temperature of the surface, and
Ta	= temperature of the surroundings.

 

Now, if we need to increase the heat transfer rate from the surface, we can:

1. increase the temperature potential, (T_s - T_a); but, this may not be possible always ...