HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
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Figure 3.6 Heat transfer in composite walls in parallel [1 ]<br />
Heat loss per unit length of the tube according to Equation 3.22:<br />
In the case of multiple-layer walls, in which the heat flow is divided into parallel flows as<br />
shown in Figure 3.6, the total heat flow is the sum of the individual heat flows. Therefore<br />
we have<br />
3.1.6 Overall Heat Transfer through Composite Walls<br />
(3.23)<br />
(3.24)<br />
If heat exchange takes place between a fluid and a wall as shown in Figure 3.7, in addition<br />
to the conduction resistance we also have convection resistance, which can be written as<br />
(3.25)<br />
where O1 - heat transfer coefficient in the boundary layer near the walls adjacent to the<br />
fluids.<br />
Fluid 1 Fluid 2<br />
Figure 3.7 Conduction and convection through a composite wall [1]