Transcript Slide 1
Professesor Crocker is building a cabin on a hillside and has proposed
the water system shown below. The distribution tank in the cabin
maintain a pressure of 30 psig above the water. There is an energy loss
of 15.5 lb-ft/lb in the piping. When the pump is delivering 40 gal/min of
water and the pump has efficiency of 72 %, what the size motor I
srequired to drive the pump.
Answer : 4,28 hp
m3
s
gal
m3
Q 40
0,00252
gal
min 15850
s
min
hL 15,5 ft
V1 V2 0
6895Pa
206850Pa
psig
p1 po
p2 po 30 psig
z1 0 z 2 (3 212 5) 220 ft
m
4,724m
3,281ft
m
67,053m hR 0
3,281ft
V12
p2
V22
z1
hA hR hL
z2
2g
2g
p po
206850
hA 2
hL z 2
4,724 67,053 92,863m
1000(9,81)
hp
PA hA q 9810992,8630(0,00250 2295,676W
3,079hp
745,7
P 3,079
PM A
4,276hp
e
0,72
p1