Más contenido relacionado



  1. TOPIC :- EXTENDED SURFACE HEAT TRANSFER 1 *ASSIGNMENT * Department of dairy Technology
  2. SUBMITTED BY :- HEMANT ARUN THAKARE Enrollment No :- D/21/059 Course code :- DE-205 (HMT) Submitted to :- Er. Santosh chopde sir Date of submission :- 05/10/2022 2
  3. • 1) Introduction • 2) Fins • 3) Why do we use fins ? • 4)Types of fins • 5)Application of extended surface • 6) Advantages / Disadvantages • 7) Some Assumption • 8) Efficiency of fins 3 INDEX
  4. INTRODUCTION :- • An extended surface (also known as a combined conduction and –convection). • Extended surfaces may exist in many situation but are commonly used as fins to enhance heat transfer by increasing the surface area available for convection 4
  5. 5
  6. • FINS :- • Fins are the extended portion of surfaces . • The heat is transferred from the body to fins by means the conduction then this heat from the fins Is transferred away by convection • Without use of fins is insufficient to cool or heat the Body .. 6
  7. WHY DO WE USE THEFINS? • To increase the rate of heat transfer • To maintain the engine body temperature excessive amount of heat is to be desipated • To dissipitate heat more heat transfer area is needed • Its helps to loose heat from engine to the air at a faster rate. 7
  8. Straight fin • TYPES OF FINS 2) Radial Fins :- Radial fins are fitted on the cylinder surface *Used in Induction type motor 1)Straight Fins:- The straight fins are arranged normally to the surface of the body and in parallel directions . These are uniform fins Radial Fin 8
  9. 3) Annular fins :- The annular fins are of annular shape fixed on the periphery of the cylinder body. Used in liquid- gas heat exchanger Annular Fin 4)Pin Fins :- The fins have a lower cross section area but in this case the surface area Exposed to the conection is more 9
  10. • APPLICATIONS OF EXTENDED SURFACE Fins are most commonly used in heat exchanging devices . • 1) Economisers for steam power plants • 2) On engine surfaces in bikes • 3) Compressors • 4) Condensors of refrigerator or AC • 5) Electric Transformer • 6) On electric motor • 7) Electric and electronic components 10
  11. 11
  12. • 1) Steady state heat conduction • 2) No internal heat generation within the fins • 3) Uniform heat transfer coefficient(h) over the e entire surface of fin • 4) Homogenous and isotropic fins material • 5) One dimensional heat conduction • 6) Negligible Radiation The following assumption are made for the analysis of heat Heat flow through fin are 12
  13. EFFICIENCY OF FINS :- 1)Fin efficiency is the ratio of heat transfer from the actual fin to the heat transfer of an imaginary fin EFFECTIVENESS:- Fin effectiveness shows the relation between the rate of Heat transfer By using fins and by without using fins 13
  14. ADVANTAGES OF FIN :- • Increase the rate of heat transfer • Easy and cheap way For cooling of equipment’s • Its not necessary to increase the Convective heat transfer By using the differentcooling medium Disadvantage :- • The weight of body increase due to the Fins . 14
  15. THANKING YOU .. 15