Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
HEAT TRANSFER
Dr. Basavaraj K. Nanjwade M. Pharm., Ph. D
Department of Pharmaceutics
Faculty of Pharmacy
Omer Al-Mukhtar U...
CONTENTS
• Mechanisms of heat transfer
• Fourier’s law
• Single and compound wall resistance in series
• Film coefficient
...
Mechanisms of heat transfer
• Heat transfer from one place to another takes place by
three different mechanisms and all th...
• Convection is the transfer of thermal energy by the
actual motion of the medium itself. The medium in
motion is usually ...
Heat transfer applications
1. Evaporation: heat is supplied in order to convert a
liquid into a vapor.
2. Distillation: he...
2014/06/03
Faculty of Pharmacy, Omer Ali-Mukhtar University,
Tobruk, Libya.
6
Fourier’s law
Single and compound wall
resistance in series
• Up to now a wall has been treated as if it consisted of
only one material....
2014/06/03
Faculty of Pharmacy, Omer Ali-Mukhtar University,
Tobruk, Libya.
8
Let us assume that the inside wall is the ho...
Film coefficient
• Film coefficient, in thermodynamics and in mechanics is
the proportionality coefficient between the hea...
Stephan-Boltzmman law
• The thermal energy radiated by a blackbody
radiator per second per unit area is proportional to th...
Tubular heaters or heat
exchangers
• It is the simplest form of heater. It is single pass tubular
heater.
• Construction: ...
• Working:
1. Steam is introduced and it flows down the tubes
2. In this process tubes get heated, the condensate vapor dr...
Advantages:
• Large heating surface can be packed into small
volume.
Disadvantages:
1. Velocity of fluid is low because of...
THANK YOUE-mail: nanjwadebk@gmail.com
2014/06/03 14
Faculty of Pharmacy, Omer Ali-Mukhtar University,
Tobruk, Libya.
You’ve finished this document.
Download and read it offline.
Upcoming SlideShare
Introduction to heat transfer
Next
Upcoming SlideShare
Introduction to heat transfer
Next
Download to read offline and view in fullscreen.

Share

Heat Transfer

Download to read offline

Heat Transfer

Related Audiobooks

Free with a 30 day trial from Scribd

See all

Heat Transfer

  1. 1. HEAT TRANSFER Dr. Basavaraj K. Nanjwade M. Pharm., Ph. D Department of Pharmaceutics Faculty of Pharmacy Omer Al-Mukhtar University Tobruk, Libya. E-mail: nanjwadebk@gmail.com 2014/06/03 1 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  2. 2. CONTENTS • Mechanisms of heat transfer • Fourier’s law • Single and compound wall resistance in series • Film coefficient • Stephan-Boltzmman law • Tubular heaters or heat exchangers • References 2014/06/03 2 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  3. 3. Mechanisms of heat transfer • Heat transfer from one place to another takes place by three different mechanisms and all three may occur simultaneously. 1. Convection 2. Conduction 3. Radiation 2014/06/03 3 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  4. 4. • Convection is the transfer of thermal energy by the actual motion of the medium itself. The medium in motion is usually a gas or a liquid. Convection is the most important heat transfer process for liquids and gases. • Conduction is the transfer of thermal energy by molecular action, without any motion of the medium. Conduction can occur in solids, liquids, and gases, but it is usually most important in solids. • Radiation is a transfer of thermal energy by electromagnetic waves. 2014/06/03 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya. 4 Mechanisms of heat transfer
  5. 5. Heat transfer applications 1. Evaporation: heat is supplied in order to convert a liquid into a vapor. 2. Distillation: heat is supplied to the liquid mixture for separation of individual vapor component. 3. Drying: for drying the wet granules. 4. Crystallization: saturated solution is heated to bring out super saturation, which promotes crystallization of drugs. 5. Sterilization: Autoclaves are used with stream as a heating medium. 6. Heat transfer is required for refrigeration. 2014/06/03 5 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  6. 6. 2014/06/03 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya. 6 Fourier’s law
  7. 7. Single and compound wall resistance in series • Up to now a wall has been treated as if it consisted of only one material. • Walls are made up of many different materials of different thicknesses. • We solve this more general problem by considering the compound wall. 2014/06/03 7 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  8. 8. 2014/06/03 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya. 8 Let us assume that the inside wall is the hot wall and it is at a temperature Th, whereas the outside wall is the cold wall and it is at a temperature Tc. The temperature at the interface of the two materials is unknown at this time and will be designated by Tx. The first wall has a thickness d1, and a thermal conductivity k1, whereas wall 2 has a thickness d2, and a thermal conductivity k2. Single and compound wall resistance in series
  9. 9. Film coefficient • Film coefficient, in thermodynamics and in mechanics is the proportionality coefficient between the heat flux and the thermodynamic driving force for the flow of heat (i.e., the temperature difference, ΔT): Where • q" : heat flux, W/m2 i.e., thermal power per unit area, q = dQ/dAh : heat transfer coefficient, W/(m2 •K)ΔT : difference in temperature between the solid surface and surrounding fluid area, K 2014/06/03 9 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  10. 10. Stephan-Boltzmman law • The thermal energy radiated by a blackbody radiator per second per unit area is proportional to the fourth power of the absolute temperature and is given by 2014/06/03 10 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  11. 11. Tubular heaters or heat exchangers • It is the simplest form of heater. It is single pass tubular heater. • Construction: It consists of bundle of parallel tubes relatively thin walled. Ends of tubes are expanded into two sheets. Bundles of tubes are enclosed in a cylindrical shell. Two distribution chambers are provided at each end. Fluid inlet is provided to left distribution chamber. Heated fluid outlet is provided to right distribution chamber. Steam is provided by connections, non condensate vapor escape through vent. Condensate vapor drains at the bottom. 2014/06/03 11 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  12. 12. • Working: 1. Steam is introduced and it flows down the tubes 2. In this process tubes get heated, the condensate vapor drained. 3. Non condensate gases escape through vent 4. The fluid to be heated is pumped into the left distribution chamber 5. The fluid flows through the tube and steam and fluid are separated physically. 6. The total heat transfer is affected by the single pass of the fluid 7. Thus the fluid reaches the right distribution chamber and leaves through the exit point. Tubular heaters or heat exchangers 2014/06/03 12 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  13. 13. Advantages: • Large heating surface can be packed into small volume. Disadvantages: 1. Velocity of fluid is low because of large cross section area. 2. Due to high temperature loosening and leakage take place. Tubular heaters or heat exchangers 2014/06/03 13 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  14. 14. THANK YOUE-mail: nanjwadebk@gmail.com 2014/06/03 14 Faculty of Pharmacy, Omer Ali-Mukhtar University, Tobruk, Libya.
  • shraddhasingh64

    Jul. 12, 2021
  • SwapnilShevalkar

    Feb. 26, 2021
  • SandeepCh28

    Jan. 8, 2021
  • AakratiSingh1

    Jan. 8, 2021
  • AcksonMunshya

    Dec. 3, 2020
  • PariaAld

    Nov. 30, 2020
  • kushagrashukla19

    Nov. 26, 2020
  • SandhyaPunetha1

    Oct. 6, 2020
  • NahedaAnjum

    Aug. 12, 2020
  • SainiSingh4

    Aug. 10, 2020
  • SuprathikaReddy

    Jul. 13, 2020
  • Arhammmm

    Apr. 24, 2020
  • ARJUNPRAKASH48

    Dec. 25, 2019
  • DRxRimpalKanyal

    Dec. 21, 2019
  • Rohitdhiman00

    Dec. 7, 2019
  • ParaniParani

    Nov. 14, 2019
  • DivyaDevi18

    Oct. 23, 2019
  • Abdullateefshaik

    Oct. 1, 2019
  • MukeshPatel245

    Sep. 25, 2019
  • Manukondubhaskar

    Aug. 18, 2019

Heat Transfer

Views

Total views

19,401

On Slideshare

0

From embeds

0

Number of embeds

14

Actions

Downloads

630

Shares

0

Comments

0

Likes

29

×