Heat Transfer: Conduction

ð It seems reasonable (intuitive) and it has been found experimentally that the rate of heat flow through a substance is        proportional (here we go again) to the following        Ø the thickness of the substance (l): Inversely proportional        Ø the difference in temperature between the ends (T1 - T2): Directly proportional        Ø The cross-sectional area of the substance: Directly proportional ð Using k for the proportionality constant and t for time we can write the following equation        Q/t = kA(T1 - T2)/l ð k is referred to as the thermal conductivity, a property of the substance. ð Following the usual approach, we find k through experiments. A table of k for various substances if shown below.

 

 

Some Thermal Conductivities