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Heat TransferConductive heat transfer is the movement of heat through solids or between two solids that are touching. An example of conductive heat transfer is common when cooking on the stovetop. We set the pan on top of the stove. The stove heats the pan at the bottom of the pan, but it is not just the bottom of the pan that gets hot. The handle of the pan often gets hot also. This is because conduction occurs within the pan that transfers the heat from the bottom of the pan, throughout the pan to the handle. In the potato example, heat is conducted from the oven rack that the potato is sitting on, to the potato skin, and again from the outside of the potato to the inner potato. When hot food is placed on a cold plate, heat is transferred via conduction from the hot food that is touching the plate to the plate. Conductive heat transfer can be represented by a basic equation. Our task is to introduce this equation and dissect it into understandable parts. Q = -kA(D T)/(D x) Each symbol stands for a different quantity.
Example: Joules (J), kilojoules (kJ), ergs, calories (cal), kilocalories (kcal), Newton-meters (Nm), or BTU’s
Example: Btu / (h * ft * oF)
A = b * c
A = P r2
Example: m2, cm2, ft2, miles2
Therefore, returning to the equation, Q = -kA(D T)/(D x) It was shown that the equation above describes that the heat of the system is equal to the negative thermal conductivity times the area, times the change in temperature across the length of the object divided by the length of the object. Proceed to Conduction Example Return to Heat Transfer [Introduction | Kinetics | Heat Transfer | Mass Transfer | Bibliography] This project was funded in part by the National Science Foundation and is advised by Dr. Masel and Dr. Blowers at the University of Illinois. |
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