SOLUTION MANUAL FOR HEAT TRANSFER THROUGH EXTENDED SURFACES

HEAT TRANSFER THROUGH
EXTENDED SURFACES (FINS)

Prepared by:
Ankur Sachdeva
Assistant Professor, ME

, Introduction
• The rate of heat transfer from a surface at a
temperature Ts to the surrounding medium at T∞ is
given by Newton’s law of cooling as
𝑄ሶ = ℎ𝐴𝑠 (𝑇𝑠 − 𝑇∞ )
• where As is the heat transfer surface area and h is the
convection heat transfer coefficient.
• When the temperatures Ts and T∞ are fixed by design
considerations, as is often the case, there are two ways
to increase the rate of heat transfer:
– to increase the convection heat transfer coefficient h
– to increase the surface area As

Ankur Sachdeva, Assistant Professor, ME

, Extended Surfaces or Fins
• Fins are surfaces that extend from an object to
increase the rate of heat transfer to or from the
environment by increasing convection.
Examples
1. Air cooled I.C. engines
2. Refrigeration condenser tubes
3. Electric transformers
4. Reciprocating air compressors
5. Semiconductor devices
6. Automobile radiator
Ankur Sachdeva, Assistant Professor, ME

, Applications of Fins



Automobile Radiator
Oil-Cooled Transformers

Air-Cooled Engines




Induction Motor Condenser
Ankur Sachdeva, Assistant Professor, ME