Answer:
t= 4.5 mm
Explanation:
Given that
P = 520 KPa ( gauge)
Maximum allowable normal stress ,σ= 150
d= 2.6 m
Wall thickness = t
The normal stress for pressure vessel given as
( hoop stress)
We always take maximum stress for safe design.
Now by putting the values
t= 4.5 mm
So the minimum thickness, t, of the wall is 4.5 mm
C. seems like the best answer. i may be wrong so don’t quote me on that
Answer:
14.52 minutes
<u>OR</u>
14 minutes and 31 seconds
Explanation:
Let's first start by mentioning the specific heat of air at constant volume. We consider constant volume and NOT constant pressure because the volume of the room remains constant while pressure may vary.
Specific heat at constant volume at 27°C = 0.718 kJ/kg*K
Initial temperature of room (in kelvin) = 283.15 K
Final temperature (required) of room = 293.15 K
Mass of air in room= volume * density= (4 * 5 * 7) * (1.204 kg/m3) = 168.56kg
Heat required at constant volume: 0.718 * (change in temp) * (mass of air)
Heat required = 0.718 * (293.15 - 283.15) * (168.56) = 1,210.26 kJ
Time taken for temperature rise: heat required / (rate of heat change)
Where rate of heat change = 10000 - 5000 = 5000 kJ/hr
Time taken = 1210.26 / 5000 = 0.24205 hours
Converted to minutes = 0.24205 * 60 = 14.52 minutes
