1. Done by: Sean Lee 3S2-12 Kenneth Leong 3S3-05 Yong Sheng 3S3-22

2. Introduction  Low velocities and high viscosity causes Laminar Flow  Laminar flow is not good in the transfer of heat energy

3. Viscosity  Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or extensional stress.  Affected by the temperature.  Raising the temperature of a fluid tends to make it less viscous.  E.g. Oil stored in the fridge

4. Viscosity  Low viscosity <2 or <3 centipose(cP).  High viscosity is around 50 centipose(cP).  Tap water has around 1 cP. The more viscous, the slower the fluid flows.  High viscosity, e.g. Glycerol, Honey  Directly affects the velocity of the fluid flowing through the heat exchanger

5. http://en.wikipedia.org/wiki/File:Viscosity.gif

6. Viscous fluids in heat exchangers  Sugar  Petroleum

7. Velocity  Low velocities are liquids flowing at <2 or <3 ft/s  High velocities of >10 or >12 ft/s may cause erosion of metal surfaces and should be avoided.  Affects the effiency of heat energy transfer in the heat exchanger, the higher the velocity, the faster the exchange of heat energy.

8. Thank you