Consider the conditions of Example 3–14 in the text except that the ambient air is at a temperature of 30°C. A person with skin/fat layer thickness of 0.003 m is doing vigorous exercise which raises the metabolic heat generation rate from 700 to 7000 W/m³ over a period of time. Calculate the perspiration rate required in lit/s so as to maintain the skin temperature at 34°C. Use the perspiration properties to be the same as that of liquid water at the average surface skin temperature of 35.5°C.

Example 3-14

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EXAMPLE 3-14 Application of Bioheat Transfer Equation We are interested in heat transfer analysis from a human body subjected to certain environmental conditions. For this purpose consider a region of muscle with a skin/ fat layer over it under steady state conditions as shown in Fig. 3-51. For simplicity approximate this region as a one-dimensional plane wall with surface area A. The muscle thickness is Lm covered by a layer of skin/fat with a thickness Lsf. The met- abolic heat generation rate (em) and perfusion rate (p) are both constant throughout the muscle. The blood density and specific heat are p, and cb, respectively. The core body temperate (T) and the arterial blood temperature (T₂) are both assumed to be the same and constant. The muscle and the skin/fat layer thermal conduc- tivities are km and ks, respectively. The skin has an emissivity of & and the body is subjected to an air environment with a temperature of To, a convection heat trans- fer coefficient of hconv, and a radiation heat transfer coefficient of hrad. Assuming blood properties and thermal conductivities are all constant, (a) develop an expres- sion for the interface temperature (T) between the muscle and the outer skin/fat layer, and (b) determine the temperature T, and the rate of heat loss from the body (Q), and the skin temperature (T) for the following conditions: