The four horsemen of heat transfer C ontents: Conduction Convection Evaporation Radiation.
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The four horsemen of heat transfer Contents: •Conduction •Convection •Evaporation •Radiation
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Transcript of The four horsemen of heat transfer C ontents: Conduction Convection Evaporation Radiation.
The four horsemen of heat transferContents:
•Conduction•Convection•Evaporation•Radiation
Conduction
TOC
Heat transfer by contactRandom wigglingHot to coldFlow rate T, A, material, 1/thickness
Simulation
Insulation prevents conductionDown/SyntheticsThickness
Demo – Ice Melter blocks. Start the radiation demo.
Convection
TOC
Heat carried away by moving fluidMuch faster than conductionSurface layers
Examples:Sauna/cold lakeCar radiatorCooling fans on computersWind chillFirestorms
Windbreakers slow down convectionDemo – Heat Sinks and smoke box with candle
Evaporation
TOC
Heat transfer by phase changeCooling process
Whee!
If you always lose the fastest…
ExamplesCooling towers @ PSUSweat
Poly layers keep skin dryCotton = death
Radiation
TOC
Hot objects radiate photons (black body radiation)Heating up a pokerBonfire/barn fire/stovesThe sunFrost
Silver lined blankets/bags reflect radiation back to you
Demo – check temperatures on radiation demo
