Unformatted text preview: ossibly convection from the coffee to the cup wall (depending on whether the water inside is in motion.) motion.) – Conduction through the wall of the cup Conduction through – Convection from the outer wall surface to the ambient air (conduction from the wall to the air —a gas — is minimal.) minimal.) How would things change if How you were holding the cup? you Thought Experiments Thought Experiments
1. Air in a room is at Ti=20°C and air outside is Air °C To=-10°C. That means: everywhere I go in the room °C. the temperature is 20°C, whereas everywhere outside 20°C, it is -10°C. -10 What is the wall temperature? Touch the wall…touch What the window. the Draw the temperature profile Thought Experiments Thought Experiments
T Ti To
inside wall outside x Draw the temperature profile Draw the direction of heat flux q” through the wall Though Experiments Though Experiments
The temperature profile should look like
T Ti q”
inside wall outside x Note: the temperature varies con...
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