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Done by: Sean Lee 3S2-12 Kenneth Leong 3S3- 05 Yong Sheng 3S3- 22. Viscosity of fluid and its flow velocity. Introduction. Low velocities and high viscosity causes Laminar Flow Laminar flow is not good in the transfer of heat energy. Viscosity.
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Done by: Sean Lee 3S2-12 Kenneth Leong 3S3-05 Yong Sheng 3S3-22 Viscosity of fluid and its flow velocity
Introduction • Low velocities and high viscosity causes Laminar Flow • Laminar flow is not good in the transfer of heat energy
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
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
Viscous fluids in heat exchangers • Sugar • Petroleum
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.
Thank you The end