1. (25 points) Consider a gentleman generating 60 W of metabolic heat steadily w
ID: 702579 • Letter: 1
Question
1. (25 points) Consider a gentleman generating 60 W of metabolic heat steadily while doing sedentary work, and dissipating it by convection and perspiration. He is wearing clothes made of I-mm-thick synthetic fabric (k0.13 W/m °C) that covers the body completely. The ambient air is at 30°C, the heat transfer coefficient at the outer surface is 15 W/m2·°C, and the inner surface temperature of the clothes can be taken to be 32°C. Treating the body of this person as a 25-cm-diameter, 1.7-m-long cylinder determine the fraction of heat lost from him by perspiration.Explanation / Answer
Total metabolic heat = convection + perspiration
area = PI*r*h
r is radius = d/2 = 25/2 = 12.5cm
h= height =1.7m
area= 3.14*1.7*12.5*10-2 =0.667m2
60 = h*a*(32-30)+ k*a*(32-30)/l + persipiration
here h= 15 W/m2C
k=0.13 W/m C; l=1.7
60= 15*0.667*2 + 0.13*3.14*0.125*2 + persipiration
therefore heat lost by persipiration is 39.888W
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.