The tool FT-06 computes the rate of heat transfer and temperature distribution in multilayered composites. It also gives the thermal resistance of each layer and the effective thermal resistance of composites.

In addition, a tutorial on how to use the toolbox in computation is provided and a subject review on fundamental theories and useful formulas is presented.

## Tutorial

Example: A hollow sphere with three layers

The input in the toolbox is

After clicking "Run", the results will be shown as follows in another page.

Rate of Heat Transfer: 79558.12568263

Effective Thermal Resistance Reff = 0.00188541

Resistance

Resistance R1 = 0.00132629

Resistance R2 = 0.00020805

Resistance R3 = 0.00035108

Temperature Distribution

Temperature Ti = 200

Temperature T1 - 2 = 94.48275862

Temperature T2 - 3 = 77.93103448

Temperature To = 50

## Subject Review

Heat Conduction in Multilayered Composites (Lumped Parameter Model)

The heat conduction in multilayerd composites using lumped parameter model is sloved by adopting the concept thermal resistance, which is similar to the electrical resistance in electrical systems. The rate of heat transfer through multilayered composites is given by

where

Ti and To: Boundary temperature

Rtotal: Total thermal resistance

The relationship between heat flux and heat transfer rate is

where A is the area

The total thermal resistance is the summation of the thermal resistance of each layer, which is

Table 1 lists the formula to determine thermal resistance for different type of multilayered composites.

Table 1 Thermal resistance for different type of multilayered composites

### References

1. Y. A. Cengel, Heat Transfer: A Practical Approach, 2002, McGraw-Hill.