用离心泵将常温水由φ57mm乘3.5mm钢管从水池送往高位水槽

1）d=57-3.5*2 =50 mm = 0.05m
v=q/s=20/3600/s=0.707 m/s
H =z+v^2/2g+0.03*80/0.05*v^2/2g = 21.25 m
2) N = HQg*1000*9.8/0.65 = 21.25*20*1000*9.8/3600/0.65=1.78KW
3) 泵有效气蚀余量;
Hg = P0/1000/9.8 - Ps/1000/9.8 - 4 -0.03*20/0.05*v^2/2g = 5.8 mWC
有效气蚀余量大于允许气蚀余量,合适.
——不知道算没算错