Conduction - Consider a composite slab is made up out of...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Conduction Consider the slab of material shown in Figure 17.3. The left end of the beam is maintained at a temperature T H ; the right end of the beam is maintained at a temperature T C . As a result of the temperature difference heat will flow through the slab, from its hot end to its cold end. Experimentally it is shown that the rate of heat transfer (Q/t) is proportional to the cross- sectional area of the slab, proportional to the temperature difference, and inversely proportional to the length of the slab Here, k is the thermal conductivity , which is a constant that depends on the type of material. Large values of k define good heat conductors. The thermal resistance R is related to the thermal conductivity k in the following manner Figure 17.3. Conduction. Thus, the lower the thermal conductivity of the material, the higher the thermal resistance R. From the definition of R it immediately follows that
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Consider a composite slab is made up out of two different materials, with length L 1 and L 2 , and with thermal conductivity k 1 and k 2 , is placed between two heat baths (see Figure 17.4). Suppose that the temperature of the interface between the two slabs is equal to T x . The amount of heat flowing from T H to T x is given by The amount of heat flowing from T x to T C is given by Of course, the heat flowing through slab 1 must equal the heat flowing through slab 2. Thus Figure 17.4. Heat transport through a composite slab. This equation can be used to obtain the temperature at the interface between slab 1 and slab 2: The heat flowing through the slab can now be calculated easily A composite slab therefore has a thermal resistance equal to the sum of the thermal resistance of each of the individual slabs....
View Full Document

Page1 / 2

Conduction - Consider a composite slab is made up out of...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online