ChE 304
Homework #8
1. A pressurized tank of water has a 10 cm diameter orifice at the bottom, where water discharges to the atmosphere.
The water level is 3 m above the centerline of the outlet. The tank air pressure above the water level is 300 kPa
(absolute) while the atmospheric pressure is 100 kPa. Neglecting frictional effects, determine the initial discharge rate
of water from the tank in m3 ë s.
First write the BE
Solve for v2
Substitute values
p1 = 300000 Nêm2
p2 = 100000 Nêm2
g = 9810 Nêm3
g = 9.81 mês2
z1 = 0
z2 = -3 m
v1 = 0
°
V=vA
v2
v2
p1
p
+ 1 + z1 ã 2 + 2 + z2
g
2g
g
2g
2 g p1 - 2 g p2 + g v21 + 2 g g z1 - 2 g g z2
g
21.421 m
s
0.16824 m3
s