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