Rate at which a body cools?

[tacom8]

I am doing a project for school and need to do a study on the rate at which a body will cool. Being an engineering student you would have thought i would have learnt this by now... sadly no, i am an EE student and either we never did, or i just don?t remember anymore. So here is the scenario,

I have a piece of whatever, lets say a piece of nylon. And i wish to cool it to a few different temperatures (<-20oC). The nylon is being cooled directly by another object, with good thermal conductivity(metal?). So, what kinda equations am i looken at? i know its going to be dependent, on the delta temperature of the two bodies, the material properties of the two bodies, and so on... Can anyone direct me to some stuff i could read about this sorta thing? I mean this seems like it should be a real simple thermodynamics kinda problem.

The only reason i ask this is that i have no clue what to type into google to even begin to figure out a solution. And, please note this IS NOT AN ASSINGMENT, but rather a project with components outside the scope of my studies. And why ask here?, well we are actually using TECs, so i was just figuring that anyone that put together a peltier cooler for their cpu probably went through similar questions.

thanks for the help!

 

[esun]

Look up rate of heat transfer. The basic equation is really simple,

/\Q//\dt = kA/l * (T1-T2)

for T1 > T2. k = thermal conductivity of whatever you're studying. A = cross sectional area of the conductor. l = length of the conductor. Also, /\ = delta above.

The differential version is obvious from the above as

dQ/dt = -kAdT/dx

You could also look up Newton's Law of Cooling (it should be very easy to find information on).

 

[rgwalt]

Bodies lose heat by three different ways:

1) Conduction
2) Convection
3) Radiation

If you are looking at the cooling of a solid body when in contact with another solid body, that is conduction. The cooling of a solid body in contact with a liquid or a gas is convection. Radiation is a different story, and is typically neglected for many applications.

Try searching for the term "heat transfer". You should find a good, basic introduction to the different modes of heat transfer.

Ryan