Suppose 150w of heat flows by conduction from the blood capillaries beneath the skin to the body's surface area of 1.5 m^2. if the temperature difference is 0.50 ºc, estimate the average distance of capillaries below the skin surface. use 'mm' as your units.

Explanation:

Given:

Rate of heat transfer, P = 150 W

Body surface Area, A = 1.5 m²

Temperature difference, ΔT = 0.50°C

Also,

The rate of heat transfer, P is given as:

Where,

l =length of material (or here it isaverage distance of the capillaries below the skin surface)

k = Thermal conductivity

Here the transfer of heat is through the skin. Thus, k for human tissue is given as 0.2

substituting the values in the above equation, we get

or

or