• Understand the Fourier Law of heat conduction and the usage of its equation in determining the rate of heat flow via solid materials.
II. Theory :
The Fourier Rate Equation:
When a plane section of ∆x and a constant area A maintains a temperature difference ∆T, then the heat transfer rate per unit time by conduction through the wall is found to be:
Q α A ∆T/∆x where ∆x = (xb – xa )
And the electrical heating Q = V.I
If the material of the wall is homogeneous and has a thermal conductivity C (the constant of proportionality) then:
Q = C ∆T/∆x where ∆T = (Ta – Tb )
If the surfaces of the heated and cooled sections are attached tightly together, and are in good thermal contact, then the 2 sections can be considered as a continuous homogenous composite sample of uniform cross section of material.
Q = A.Khot.∆Thot/∆xhot = A.Kcold.∆Tcold/∆xcold
III. Tools (Equipments) :
• The heated section is manufactured from 25 mm diameter cylindrical brass bar with an electric heating element installed at one end. • The cooled section is manufactured from 25 mm diameter cylindrical brass bar to match the heating section and cooled at one end by water passing through in and out the section. • 6 fix type K thermocouples and 2 type K thermocouples used only with brass Speciemen. Three thermocouples (T1, T2 and T3) are positioned along the heated section at uniform distance of 15 mm to measure the temperature transfer along the section. Three other thermocouples (T6, T7 and T8) are positioned along the cooled section at uniform distance of 15 mm to measure the temperature transfer along this section. • 2 thermocouples ( T4 and T5) are also fitted with a distance of 15 mm apart for a 30 mm long brass...